Forget Space Travel, It's Just a Dream

An anonymous reader writes "The clash of two titans — physics and chemistry — are major barriers to human space travel to Mars and beyond, and may well make it impossible ... at least with current technologies."

Comments

Math

[Anonymous Coward]

If it is impossible in the real world, why not solve it with math?

Re:Math

[Daimanta]

I looked into it (math undergrad) and I devised a way to shorten the lengthy spacetravel to Mars from 3 months to 1 + i months! Now, the only thing I have to do is to think of a way that lets people travel in complex time, but I think that it won't be too hard to solve.

Re:Math

[beschra]

The farmer's cow wasn't giving milk like she used to. He knew there was a very clever mathematics professor with a hobby farm down the road and figured he might be able to help. Farmer explains problem to math guy and math guy says to come back in a week. Farmer comes back in a week and math guy says he's solved the problem! "First, assume a spherical cow ..." (My Calc II prof got the same reaction from us)

Re:Math

[GooberToo]

and may well make it impossible ... at least with current technologies.

When you make a prediction about the future and balance your entire argument based on current technology, you basically confirmed you're an idiot. The same absolute fucking idiots all said we can't fly, you'll suffocate in a car when it moves, reaching orbit is impossible, small electronic radio devices are nothing but scifi.

The summary could have simply said, "today's technology has limits."

So please, can we stop posting articles by fucktards, for fucktards?

Re:Math

[Giant Electronic Bra]

OK, so explain to me how you will get past the laws of physics then? Your statement is equivalent to "All you assholes that say perpetual motion can't be achieved are just pessimistic fucktards." Yeah, right...

Fundamentally the guy is correct. He may be incorrect in that we could build large nuclear powered VASIMIR / magnetohydrodynamic rockets, but those can't lift off from the Earth (insufficient specific impulse). Even if we built such a thing it only extends our range of action slightly. Someone might be able to go to Mars, but then you'll want to go further, and then you run into the real wall because Mars is nothing, that's like going next door. Nor is there anything particularly compelling about Mars. Antarctica is 1000's of times more habitable and nobody wants to live their either. As a target for a science mission? Sure.

Re:Math

[gnick]

What's with the hate? Just because you've seen a helicopter in the air doesn't mean they can fly! - Do the math yourself and it'll prove it. I do partially yield however to "proof by reality".

But yeah, I think that we can sum this up by saying, "There are things we can't do yet."

Re:Math

[Z00L00K]

It always comes back to "it's impossible", "can't be done" and so on, then someone does it in an unexpected way and the rest of the world stands there looking stupid.

Even if it looks mathematically impossible using regular math you may end up with a great solution using an unexpected approach on math - or you will need to develop the math after the fact has been proven.

Re:Math

[GooberToo]

"There are things we can't do yet."

That's entirely the point. Basically, everything you do every day was once, "impossible." And it was believed in absolute terms, your daily life is literally impossible. And yet, they were all wrong.

An even better summary is, "small minded people get trapped in their own reality."

Re:Math

[Quiet_Desperation]

Just rotate the ship 90 degrees.

Re:Math

[Nutria]

It always comes back to "it's impossible", "can't be done" and so on, then someone does it in an unexpected way and the rest of the world stands there looking stupid.

But it is impossible using current technology. Discover some new energy source that can be practically converted to high-thrust propulsion and we'll all cheer you.

Re:Math

[jonadab]

Actually, it's simpler than that. Manned travel to Mars is *possible* with the technology of the 1980s -- grossly uneconomic, but possible. You just have to make a fewhundred thousand rocket flights from Earth's surface out to someplace with a more lenient gravity well (like, say, Earth's L2 point just on the far side of the Moon) and assemble your interplanetary ship and launch from there. When you get to Mars you leave the interplanetary craft in orbit and take down only what you need on the surface, plus enough rocket power to get you back up and enough more to slow your descent on the way down. It's an incredibly expensive trip, and the participants would probably develop a rather severe case of cabin fever, but it's physically possible.

Why haven't we done it, then? There's not enough incentive. It's thousands of times cheaper and easier to send robotic probes, and we get very nearly 100% of the benefit of sending a manned expedition.

Note too that while a manned expedition is theoretically possible, given enough funding, long-term colonization really isn't, because there's no way for any colony on Mars to provide for its ongoing needs. There's not enough atmosphere to support life, and keeping everything in a pressurized bubble all the time requires a continuous supply of materials and energy that cannot be produced locally. Even if you could somehow transport a nuclear reactor to Mars, there's no practical way to keep it cooled and maintained, and even if you could it only solves the energy problem. You still need a constant supply of materials and equipment, which would have to come from Earth, at enormous expense. The colony could never produce enough value to pay for that, so it could never be independent -- not with today's technology, anyhow. A colony in a bubble on the ocean floor would be *much* cheaper to build and maintain and produce *much* more value in trade goods and services (not least tourism), but nobody's yet managed to finance one, which should tell you something.

Re:Math

[LordNacho]

Not to be pedantic or anything, but isn't 1 + i at a 45deg angle to 3?

Re:Math

[coastwalker]

Actually the article isn't about the lack of a technology, it was saying that most people are too thick to understand that the laws of physics and chemistry rule out interplanetary flight (I bet you all the tea in china that a human never visits our nearest star). You kids have been spoilt by Moors law, yes we can double compute power every 18 months - but get this - you are still driving an automobile which is no more efficient than one from 100 years ago. The American government cant even afford to go back to the moon forty years after its first visit because the rockets cant get any cheaper. The only thing that will make space travel possible isn't a new technology - its a new science - and get this, unless the LHC can find some then there wont be any in your lifetime. I'm actually quite pleased about this because you dont deserve to live in a society that has space travel.

Re:Math

[spyfrog]

But that isn't true.
Cars today are much more efficient and better than they were 100 years ago. They don't evolve as fast as computer but they have evolved. And cars evolved FAST the first years they existed - computers are still a young.

Besides, it is wrong to say that nothing will evolve just because they haven't evolved for years. Take ships as an example - there wasn't much development in ships between the 15th century and the 18th century. Then the steam engine came and changed everything during the 19th century.

Re:Math

[KhabaLox]

1+i factorial months sounds like a long time.

Re:Math

[fremsley471]

Like the joke, though I feel it works better with a millionaire gambler and race horses.

Re:Math

[CubicleView]

The problem is the limits of the laws of physics, not the limits of a technology that utilizes them.

Re:Math

[Grishnakh]

It doesn't take a new energy source at all. This article was utterly idiotic, making stupid claims about the physical limits of chemical rockets. Who cares about chemical rockets? If you need more energy, we invented this thing decades ago called "nuclear power". Nuclear rockets have been theorized for ages, and the US was even going to build some back in the 60s, but NASA's budget got cut and humanity hasn't done anything interesting in space since.

It's very simple: if you need very high-energy propulsion, and chemical rockets aren't powerful enough, switch to nuclear. As a bonus, radiation and nuclear waste aren't concerns in the vacuum of space. It'd probably be a good idea to use chemical rockets for getting everything into orbit for final assembly, however.

Re:Math

[Shotgun]

OK, so explain to me how you will get past the laws of physics then?

You don't "get around" the laws of physics, you work with them.

First off, you don't depend on chemical rockets. You have a celestial based laser propulsion system so you don't have to carry all your fuel outbound. You go nuclear for the return trip.

Sit down sometime and read a pre-1900 machinist's manual. You would say that it was impossible to do some of the things people used to take for granted. After a while, you stop saying things like "can't be done".

Re:Math

[Giant Electronic Bra]

Forget it man, us fucktards are too stupid to understand...

Actually I put our situation with science like this. We're like late 18th century explorers. We KNOW the outline of the continents. Oh, there may still be an Australia out there we are only dimly aware of and there are MANY things yet to be discovered. Yet the basic outline IS known. Boundaries CAN be set on what is going to be possible. We'll find some neat tricks, maybe even good enough ones to venture off our planet one day, but they aren't going to set aside the laws we know now.

You can compare with 19th century classical physics etc all you want, but they really DIDN'T know enough to draw even the outlines.

Nobody is advocating giving up on doing science Mr Goobertoo. Please don't put words in my mouth, cheap rhetoric and name-calling? You're kidding yourself if you think you're impressing anyone that matters.

Re:Math

[Giant Electronic Bra]

Didn't I mention nuclear power? We're quite a long ways from convincing people that it would be wise to launch gigawatt scale thermal/nuclear power plants, nor have we really got a good design (yes, there are prototype designs that were developed in the 60's). It is not going to be easy to get that to happen, nor quick. Building really large scale propulsion lasers? Heh, they need to go in space, good luck.

Honestly, I've worked on rockets, you know, big ones that go into space, with people inside them even. ANYTHING you want off the Earth is going up on one of those. If it isn't going up on one of those it is going up using some machine with equal or greater power densities.

Rocket science isn't a synonym for REALLY HARD for nothing. Physics. You can't build a nuclear/thermal power plant with enough specific impulse to lift off in 1g. You still need rockets. In 100 years? Hard to say, but I'll firmly predict it still be pretty expensive and fundamentally new physics will play little, if any, part. Where it does appear it is going to be materials and control systems. There's no 'anti-gravity' hiding out there.

Re:Math

[Dr Max]

The laws of chemistry could have very little to do with interplanetary space flight (rockets is what the Nazis came up with 40 years ago). The problem with people like you is no imagination, until something is put in the newspapers or on slashdot it can't exist. Once we figure out how to revive people after cryogenic freezing any star is the limit. I wonder what people like you were saying about atomic energy before little and big boy.

Re:Math

[DanielRavenNest]

The argument that he started with is correct. Reaching earth orbit requires twice as much energy (30 MJ/kg ) as contained in good rocket fuel ( 15 MJ/kg ), therefore it is hard to get off the planet with conventional chemical rockets. There are plenty of ways to get off the planet besides conventional chemical rockets, however.

A simple example is using jet fuel in an air-breathing engine. That provides around 43 MJ/kg because you are getting the oxygen from the airflow, rather than a huge tank of oxygen like most rockets have. It's more than enough energy to get to orbit if you could use air-breathing engines all the way to space. You can't do that for obvious reasons, but if you can use air-breathing engines for *enough* of the trip, and ordinary rocket for the rest, you can have a workable system.

As far as the VASIMR plasma rocket, it has plenty of performance, but lacks enough thrust to get off the ground. You can, however combine it with a partial space elevator. A full one that goes all the way from the ground to space needs stronger materials than we have right now. But a partial one in the form of a vertical cable in orbit gives you a landing platform at the bottom that is sub-orbital. So whatever vehicle you fly up to the platform can use less propulsion. You elevator up the rest of the way. Hauling the cargo up will result in dragging the cable down, so you run your plasma rocket on a continuous basis to make that up. In effect the cable lets you concentrate the high efficiency, low thrust plasma rocket push into short term lift of cargoes.

Re:Math

[Dr Max]

We have demonstrated anti gravity on mice. We could use hydrogen filled ballons or electromagnetic sled accelerators to launch stuff into orbit and built it up there. Thats if we can't get funding for a space elevator.

Re:Math

[Giant Electronic Bra]

Yes, but there are large and almost entirely uncharacterized issues with even a 'sky hook'. It probably could be done, but even just the basics are a VERY steep engineering challenge. For instance in order to make the rendezvous happen at a reasonable relative velocity requires a great deal of control, and still requires materials of extraordinary strength. We have virtually no experience with these kinds of structures, and putting one in space would still require lifting a very substantial mass (and having the capability to service and refuel the drive system). First we will almost certainly require another couple of rounds of experience constructing things in orbit, another generation of rockets, better materials, etc. There may well be other serious issues we are unaware of.

In a sense it is a lot like building a large suspension bridge, except much bigger, assembled in orbit, etc. Many early bridges fell down, and that was an order of magnitude easier challenge. Even if we DID have such a technology it would only partially (at most) alleviate the cost.

Hybrid air-breathing engines are also a tough technology to develop. Some progress has been made but nobody has yet made anything even close to an actual transportation system and the R&D has been ongoing for more than 60 years. Again, something that will certainly happen. More decades and more billions will have to be spent on development. We're 30-40 years from having a really good working system IMNSHO. Things do get easier with better materials, control systems, and engineering/modeling etc.

Remember too, even a hybrid system will not be some routine flying like building a 747 and flying it around. You're talking about tremendous power densities, ultra-high temperatures, etc. Flying on a giant controlled explosion from standing start to Mach 11 in under 10 minutes will NEVER be cheap or routine.

Re:Math

[Giant Electronic Bra]

Yeah, that ain't anti-gravity, it is a nice diamagnetic effect, but don't expect land speeders and tie fighters anytime soon (as in ever).

Hydrogen balloons or aerostats/etc as have been proposed don't really solve the primary problem. You have to be traveling around 8,000 m/s to orbit the Earth, and that's essentially horizontal velocity, which being lofted on a balloon doesn't give you any extra of. Getting to say 200 km altitude straight up requires maybe 1/50th of the energy required for orbit. A balloon/air launch doesn't hurt, but it only reduces the size of the rocket required slightly.

We could launch stuff with a rail gun, but to launch a human into orbit using a railgun would require the gun to be something on the order of 1000 km long. You'd need several gigawatts of power as well, which probably means a couple small nuclear reactors. Again though, there are all kinds of unanswered questions about this kind of technology. We've built railguns that are maybe 1/10,000 of the size required. Scaling something up 4 orders of magnitude (while again dealing with huge power densities etc) ain't easy. Such a thing would likely cost as much as the whole ISS once you've spent the money to figure out HOW to build it. Launching hard cargo would be considerably easier but then you're talking about very high Gs. It may well simply not be economically worth it.

Re:Math

[Skywolfblue]

Note too that while a manned expedition is theoretically possible, given enough funding, long-term colonization really isn't, because there's no way for any colony on Mars to provide for its ongoing needs. There's not enough atmosphere to support life, and keeping everything in a pressurized bubble all the time requires a continuous supply of materials and energy that cannot be produced locally. Even if you could somehow transport a nuclear reactor to Mars, there's no practical way to keep it cooled and maintained, and even if you could it only solves the energy problem. You still need a constant supply of materials and equipment, which would have to come from Earth, at enormous expense. The colony could never produce enough value to pay for that, so it could never be independent -- not with today's technology, anyhow.

That assumes mars is never Terraformed. Once a planet is terraformed and self-sustaining, the price of maintaining it drops off drastically, and the value returned skyrockets. Unfortunately yes, it's both "extremely expensive upfront" and "takes a bloody long time" so it's doubtful it will ever happen.

A colony in a bubble on the ocean floor would be *much* cheaper to build and maintain and produce *much* more value in trade goods and services (not least tourism), but nobody's yet managed to finance one, which should tell you something.

This is a really good point. I think the claustrophobia aspect probably plays a larger role then expense itself here (that would go for a space colony as well). People don't like to be cooped up with no sky to wander under, or to be cut off from the rest of civilization.

Re:Math

[Dr Max]

Good point on the balloons. The trick with the rail gun is to have a circular track so you cut down on the distance and you can build speed gradually (cutting down on peak energy demand), however then you need a quick way to change the trajectory to launch it; catching it at the other end wont be a walk in the park either. It wouldn't be cheap but it could be quite profitable launching satellites and what not. Maybe if we convinced the government they could put soldiers or bombs in a pod and shoot it to any spot on the globe during the week, then it could be used for working on interplanetary exploration on weekends.

Re:Math

[GooberToo]

Boundaries CAN be set on what is going to be possible.

And that's the problem. Limits can be set based on what we *think* is possible. The FACT is, what we think is possible is frequently shown to be false because we didn't know to account for something else because we didn't even know about the something else.

This is a FACT which theoretical physicists will even point out. We don't know what we don't know. And you can't prove you don't know what you don't know. As such, to condemn tomorrow knowing full well you don't know what tomorrow brings squarely classifies one as a fucktard. Furthermore, to rationalize that you know what you don't know is the height of concept of stupidity - which in turn brings us full circle to fucktards.

The reality is, we know very little. For your position to have any merit means you can prove a negative, seen the future, or are a fucktard. I'm betting on the later.

Re:Math

[AmiMoJo]

You can get to Mars and back with chemical rockets. You pack enough fuel to get there on Earth. Maybe lift some of it into space first so you don't have to burn it up at take-off. It might take a year to get to Mars that way but that is do-able.

Once you are on Mars you can manufacture more fuel to get back. In the interests of safety it might be a good idea to send a robotic factory that will create enough fuel to get you home before you go there yourself. Due to lower gravity and a less dense atmosphere you don't need as much fuel coming back anyway.

There are also things like ion engines that you can power with solar or nuclear (and which would be ideal for manoeuvring) but it can be done entirely on chemicals if required.

Re:Math

[Giant Electronic Bra]

Yeah, the Pentagon has outlined that design. The rough part is still the forces exerted on the payload at launch. It will work fine for an artillery shell, not so well for say a satellite. Still worth working on. The big issue will be finding a good reason to build a big one.

This is where it always starts to get rough. What is the application that will make it economically advantageous? By the time you spend the couple of 10's of billions to work out how to build a working production system, build it, and amortize the costs over the limited amount of space launch capacity we currently require it doesn't look great. I'd imagine we'd come up with applications, but there's not a vast motivation for anyone to invest in it. Space is a chicken-and-egg problem. Would easily be solvable with a bit of govt investment, except the 'bit' is a big heap of money in this case.

Re:Math

[Giant Electronic Bra]

Yeah, whatever. Every dickhead on the net thinks he's some kind of expert. Show me some credentials Doc. You people simply don't grasp the situation. There are no radically new physics at low energies. It is very true that we don't understand the interior of the 'continent', but once you've circumnavigated the thing you can say with a pretty high degree of certainty there's no passage to India. Like it or not that is the situation we're in. Time machines, warp drive, vacuum energy, anti-gravity, etc are NOT POSSIBLE. That isn't a statement of denial of ignorance, it is a statement made from a position of understanding physics and the deep implications of what we observe in the world around us.

Are there potentially ways to say make anti-matter cheaply and efficiently? That's a possibility. Some tricks which could make fusion much easier? Yup, that's possible too. What you have to understand is that even with some technology like that manned spaceflight is always going to be horrendously expensive. Frankly I predict no manned space mission will ever leave near-Earth space. I know you'll hate to hear that, but all your wish-fulfillment fantasies won't make the space faerie come and bless you, nor the physics faerie either. Sorry.

Re:Math

[Keith Henson]

You do have to solve it with math, it's called the rocket equation.

The best chemical reactions give an exhaust velocity of about 4.5 km/sec. You need twice that much to get a substantial payload into LEO without staging (which is very expensive).

However, chemical reactions are not the only way to heat a gas and hydrogen heated with lasers to 600 deg less than the melting point of tungsten gives more than twice the exhaust velocity of the SSME.

This wasn't possible to consider until recent times when high power semiconductor laser diodes came on the market.

The air breathing Skylon used for a "first stage" has an equivalent exhaust velocity of 10.5 km/sec until it runs out of air at 26 km and 2 km/s. Switching to laser heated hydrogen at that point would put 1/3 of it's takeoff mass in LEO--about 50 tons of rocket plane and 50 tons of payload..

It does take a lot of laser power, about 6 GW, but we can draw that off the grid (in a few places).

Keith Henson

Re:Math

[Grishnakh]

Sounds good; I'm not a rocket scientist or engineer, so I was really only addressing the article's claim that chemistry is at its limits for energy per unit weight. The obvious solution is nuclear, if you need more energy per weight, and this article acts like nuclear energy doesn't even exist.

Now if chemical rockets are indeed good enough and more economical for human flights to inner system planets, that's great, but I was rather annoyed at the article writer for completely ignoring the nuclear option, and acting like we're at a brick wall because of the limits of chemistry when we found a way around those limits way back in the 1940s, and nuclear rockets have been planned and maybe even designed for some time now.

Re:Math

[coastwalker]

Apparently we are to bet the future on the basis of unknown unknowns rather than anything we do know - surely this verging on optimistic fantasy?

Re:Math

[Dr Max]

If we can cope with re-entry into the atmosphere and we are launching probes into some of the harshest environments around, I think we can deal with the forces on the payload. We have roughly 4000 satellites in orbit at the moment, and i would expect the same number of launches over the next 20-40 years. As old tech comes down and new tech we want up there becomes available. Currently it can cost up to $50, 000, 000 to launch a satellite it doesn’t take that many of those to make it economically feasible. If that’s not enough and the military don’t want to rent it, we could start a same hour package delivery service to any latitude or longitude on earth (if we cross a time zone it might actully arive in the past).

Re:Math

[Giant Electronic Bra]

Even assuming we launch another 4000 satellites in the next 40 years that's $5 Billion a year. Now, you are going to save what percentage of that? Half? Say you can charge 2.5 billion a year, you have 10% profit, and so if I could build the facility and provide the technology to make satellites usable with it for say $20 billion it might be worth it. Obviously it isn't considered that cheap or low enough risk yet, and making satellites survive a 1000g launch is non-trivial (way non-trivial).

Re:Math

[orangesquid]

Exactly--that's the second thing that popped into my head---land a fuel factory before sending humans. (The first thing was to land a few solid rockets that could be attached to the humans' rocket once the humans landed to enable them to return, but then I thought a fuel factory would be a better use of rocket launches, since it could be used for many go-there-and-come-back missions.)

It's funny to me that the author of the article didn't consider how we launch rockets off of the earth in the first place (by manufacturing fuel) before writing the article.

Re:Math

[Dr Max]

We could argue numbers all day I’ll round down while you round up (i can't find the original new scientest article but i seem to recall them saying it would slash launch costs to 1/10th if not 1/100th the conventional price) but i'll give in due to the fact that if it was truly profitable, as well as expanding our exploration foot print, some one would be building one (maybe the gfc slowed it down). It wont be any where near 1000gs because you can build the speed up gradually (and providing you have a large enough radius). The heat build up once it leaves the vacuum of the rail gun and hits the air would be more of an issue. have a nice day.

We can get to Mars and back.

[pecosdave]

We've been able to do that since at least the early 80's.

The question is can we make it worth the trip and comfortable?
Probably not, but we need to make the trip, at least once, just so we can say we did and we can better prepare for the later real trip.

Beyond that? We don't have the tech. Not yet.

Re:We can get to Mars and back.

[pecosdave]

Not tested and proven with human on-board anyways. Ion propulsion, solar sails and nuke ships are all possibilities of course.

The big argument against the nuke ship is the radiation left behind when it launches. I'm more of a fan of building the thing in space with chemical rocket or projectile launch methods and then assembling it in orbit, escaping earth with chemicals rockets, THEN dropping nukes to go forward.

Re:We can get to Mars and back.

[binarylarry]

Yes, we can't allow all that radiation to leak into space!

Re:We can get to Mars and back.

[camperdave]

There are fully contained nuclear rockets. They are called gas core nuclear rockets, or nuclear light bulbs. The reaction uses uranium hexafluoride gas, spun into a vortex. This vortex is contained within a sealed, quartz walled chamber. The reaction produces a lot of UV radiation. Quartz is transparent to the UV radiation, so it escapes the container. Propellant is run past the quartz wall and absorbs the UV radiation, and heats up, expanding in the process. Voila, a nuclear rocket with no radioactive exhaust.

Re:We can get to Mars and back.

[zill]

civilian reactor.

Off-topic, but does the military even run any reactors anymore?

Re:We can get to Mars and back.

[Maeslin]

submarines and aircraft carriers?

Re:We can get to Mars and back.

[JasterBobaMereel]

Got to space in Early 60's

Got to the moon in the late 60's

Both of these were single hop's, a trip to Mars is likely to be a staged journey, build the craft in orbit, or on the Moon, and use fuel from Space, the article assumes that the only possible way is a single hop from the earth to Mars (or further) taking everything, fuel, supplies with you.... This is impractical, but not impossible

Making predictions about future technology is foolish at best .... go and speak to anyone in the 1950's about a compter with 6,000 logic gates, contained within 40 square mm they would say that was against the laws of physics and chemistry ... but the Intel 8800 had this in 1974

Re:We can get to Mars and back.

[nschubach]

I think the GP was referring to the fact that the military didn't "own" the reactors. They were on lease from GE(?) from what I heard.

Re:We can get to Mars and back.

[cobrausn]

The Navy owns the reactors. They bring in civilian contractors for the critical repair jobs and overhauls, supplemented by military workers. Navy Nuclear Power techs (of which I was one) receive a lot of training in two years, but a Bachelors / Masters / PhD it is not.

Re:We can get to Mars and back.

[ThosLives]

At what specific impulse? You still have to have enough propellant to eject for the momentum exchange...and this is the killer: you have to carry extra mass around in order to change your velocity.

Re:We can get to Mars and back.

[koolfy]

building the thing in space with chemical rocket or projectile launch methods and then assembling it in orbit

Do you have any idea of the time and complexity needed to do even minor operations in space ? (i.e. doing some structural work on a space station)

This would take ages. Really, several generations. And cost trillions of dollars.
it sound cool, but it just isn't realistic.

Re:We can get to Mars and back.

[FauxPasIII]

Beyond that? We don't have the tech. Not yet.

But if we don't get going, will we ever create the tech? Nothing spurs innovation like a target and a very public deadline.

Re:We can get to Mars and back.

[TaoPhoenix]

I mentioned fuel in another post, but it's also important here - stage the supplies in a big string all headed to Mars and then shepherd them at the end. It's all about the fleet approach - not some huge single-fail ship but a lot of auxilliary resource vessels with less sophistication just to haul big supplies.

Re:We can get to Mars and back.

[radtea]

Voila, a nuclear rocket with no radioactive exhaust.

False. Quartz is also transparent to neutrons, which will be copiuously produced by the fission reaction going on. I haven't looked at the link, and don't need to. If this thing is fission powered, there are neutrons. If there are neutrons the exhaust is going to be radioactive, unless the gas is pure helium-4, in which case the whole gas vortex UV thing is irrelevant. You can run 4He through a pebble bed reactor and have it come out non-radioactive (more or less.)

Re:We can get to Mars and back.

[Skarecrow77]

I thought the big problem with nuke ships was the momentum incurred, and shedding it in time to land without detonating on impact. Slowing down in space is a sonofabitch. On a trip to somewhere like Mars, you have to expend nearly as much energy slowing down as you did speeding up. You can't air brake into mars without one HELL of a big shield/parachute due to the relatively low atmospheric density (about 1% of earth). You basically gotta turn around and thrust directly 180' into your forward path until you're slow enough not to escape the gravitational pull of your destination.

Re:We can get to Mars and back.

[mangu]

Both of these were single hop's, a trip to Mars is likely to be a staged journey

Apollo flights were not single hops, those were considered and rejected, in favor of the dual-module mission with lunar orbit rendez-vous concept.

Re:We can get to Mars and back.

[TheDarkMaster]

Redirect the trillions of dollars that governments around the world have used to save the skin of bankers in the U.S. mortgage crisis for space research. Problem solved.

Re:We can get to Mars and back.

[Rei]

It's called aerocapture, and it's been done on the Earth-side already. Aerobraking is also a (slower) option.

Re:We can get to Mars and back.

[camperdave]

At what specific impulse? You still have to have enough propellant to eject for the momentum exchange...and this is the killer: you have to carry extra mass around in order to change your velocity. You have to carry extra mass around with chemical rockets too. The issue isn't so much how much mass of propellant you have to carry, but how much delta-V you can get out of it. That is entirely related to how much velocity you can eject the propellant with, which is in turn related to how much energy you can put into it.

In the 60's NERVA and ROVER made nuclear powered rockets. These rockets were thoroughly tested and were able to generate as much as 250,000 pounds of thrust, with an Isp of 900 seconds or better. The best chemical fuels in use today are liquid hydrogen and liquid oxygen, the stuff burned by the three Main Engines on the Space Shuttle (SSME's). The SSME's produce a maximum of about 450 Isp.

There are reports of nuclear rockets having ISPs in the 10,000s range.

Re:We can get to Mars and back.

[mangu]

If there are neutrons the exhaust is going to be radioactive, unless the gas is pure helium-4, in which case the whole gas vortex UV thing is irrelevant

If the gas is hydrogen it will not become radioactive. When a hydrogen nucleus captures a neutron it becomes non-radioactive deuterium.

Hydrogen has the added benefit that it's the best gas for a propellant, so it would be used anyway.

Re:We can get to Mars and back.

[desdinova 216]

I thought the question was wether or not there was enough profit motive to go.

Re:We can get to Mars and back.

[metamatic]

Do you have any idea of the time and complexity needed to do even minor operations in space ? (i.e. doing some structural work on a space station)

This would take ages. Really, several generations. And cost trillions of dollars.

it sound cool, but it just isn't realistic.

You're right. The idea of building something as complex as a space station in pieces, and then assembling them in space, sounds cool--but it just isn't realistic. It would take generations.

So any pictures claiming to be of such a space station are clearly fakes shot on a sound stage at a secret military base in Nevada.

Re:We can get to Mars and back.

[koolfy]

You can't compare a space station (a more or less complex set of tubes and solar panels) and an entire rocket.

The space stations has to deal with a lot less of parts, dangers, energy, movement, calculations, calibrations.. It's still hard as fuck to do on earth, so on orbit, until we have a very advanced space factory, it's just too much to do manually, piece bu piece, with astronauts to do the details.

Yes, il *will* be possible some day, but not before we build an efficient way to construct space rockets in space, and building this will take decades.

Re:We can get to Mars and back.

[geek2k5]

They could be considered a version of a single hop. After all, each Apollo mission went up on a single rocket. Single launch might be a better term.

Re:We can get to Mars and back.

[Brucelet]

Plus, the structure of a space station doesn't need tp be strong enough to withstand sustained powered flight in order to leave Earth orbit.

Re:We can get to Mars and back.

[metamatic]

You can't compare a space station (a more or less complex set of tubes and solar panels) and an entire rocket.

Why not? Both can be sent up in chunks and assembled that way. You don't think the ISS was assembled bolt by bolt, do you? The Apollo missions involved sending up entire spacecraft and launching them from orbit to the moon.

Re:We can get to Mars and back.

[nusuth]

The whole point of gas core design is that it can heat your propellant to much higher temperatures than a solid core can withstand. Radiative heating, quartz, vortex etc. are just design details to contain gas core and keep it from contacting propellant.

Re:We can get to Mars and back.

[nusuth]

I don't know about GP, but the kind of orbital assembly meant in context of Mars missions is simply docking in LEO (or for the return craft, LMO). That might not be so simple either, but not too hard. It has been demonstrated in LEO in excess of a hundred times without single major mishap. Think lunar orbit rendezvous of Apollo, rather than building a complete spacecraft in LEO.

Re:We can get to Mars and back.

[mcmonkey]

This would take ages. Really, several generations. And cost trillions of dollars. it sound cool, but it just isn't realistic.

I think you've just conceded the point.

It's entirely doable. It's a matter of people deciding it's worth the effort.

Re:We can get to Mars and back.

[Nutria]

Is there enough atmosphere on Mars?

Re:We can get to Mars and back.

[BarryHaworth]

We have the technology. It is just impossible to send humans and their living quarters and their supplies and a research station and a return vehicle and return trip supplies on a SINGLE chemical rocket. Once you start using more than one chemical rocket for this list, even at just two, it becomes possible. .

The other thing is to exploit the resources at your destination. This is basically the approach advocated by Robert Zubrin in his Mars Direct mission design. The basic scenario is:

• Send an (unmanned) return rocket to Mars. It lands with empty fuel tanks.
• On board is a small amount of hydrogen, a nuclear power source, and a chemical processing plant. This is used in combination with CO2 from the Martian atmosphere to manufacture methane and oxygen to fuel the rocket for the return trip.
• Next launch opportunity (26 months later), send a manned crew vehicle. This lands next to the return vehicle waiting on the Martian surface.
• Crew explore Mars, perform research etc, and at the end of their mission hop in the return rocket and head home.

By manufacturing fuel on Mars for the return trip, most of the objections in the original article are dispensed with.

Much more detail is given in the Wikipedia article, and also in Zubrin's book, The Case for Mars (available here). Excellent book.

Re:We can get to Mars and back.

[ThosLives]

Isp of 850 or so from NERVA is good, but a factor of two probably won't be revolutionary enough to get through the political quagmire surrounding "nuclear."

The nuclear salt-water rockets, which (theoretically) get the 10000 Isp with MN thrust capability, could not be utilized as heavy-lift. You can't have your main-lift rocket producing radioactive salt water as its exhaust stream (same reason you can't use liquid fluorine as the oxidizer for LH2, even though it has a much better Isp than LO2: HF as an exhaust product is really not fun). This would work for deep-space travel, but you really have to get to LEO first, and the ability to either put lots of fuel up there or have some in-space means to collect that fuel. While possible, this is by no means a foregone conclusion.

Re:We can get to Mars and back.

[Risen888]

Took a couple generations to learn to fly too. For that matter, we're only ~40 years into microcomputers. Nothing's realistic until you do it.

Re:We can get to Mars and back.

[kirtu]

Making predictions about future technology is foolish at best .... go and speak to anyone in the 1950's about a compter with 6,000 logic gates, contained within 40 square mm they would say that was against the laws of physics and chemistry ... but the Intel 8800 had this in 1974

But people would have reacted that way in the 50's because they didn't know about Moore's Law. In fact a person who did know about Moore's Law reacted that way to me in person when he asserted in 1977 (to a person that he regarded as an ignorant kid) that the PET and Apple machines would never lead to anything and would always be toys. I reminded him of Moore's Law which he then dismissed out of hand. So it depends on whether we have a solid basis for making predictions about the future. If we have such a basis then we can make reliable predictions. And Kurzweil does a good job of this in one of his books (it wasn't Spiritual Machines I don't think) .... as did the overly optimistic Clarke - our future is more likely something like what he envisioned in Songs of a Distant Earth - not that good but also not all that bad.

Re:We can get to Mars and back.

[camperdave]

... the political quagmire surrounding "nuclear."

This is the biggest factor against developing nuclear rockets - not the cost, not the tech, not the actual slim dangers, but the politics and fear mongering.

Re:We can get to Mars and back.

[Dr Max]

I'm not sure you want to slow down. If you can get on and off then leave it at speed orbiting the planet and use its momentum for the return journey.

Re:We can get to Mars and back.

[Rei]

The short answer: Yes.

How about

[rossdee]

a space elevator aka beanstalk aka orbital tower.

Once you get out of earths atmosphere and gravity well, you're halfway to anywhere (in the solar system)

Re:How about

[ThunderBird89]

Or even up to 90% of the way, depending on how big a detour you're willing to make to use the Interplanetary Superhighway, since it's all zero-energy trajectories.

Re:How about

[ceeam]

The problem (for biological things, like human beings) is going out of Earth magnetic shield.

Re:How about

[CastrTroy]

Could you put a big magnet on the ship to channel the cosmic beams from the sun and use them to fuel the ship some how? I'm not joking. I'm not that knowledgeable in this area of expertise. But it seems like we have two problems, too much cosmic radiation, and a need for more fuel while in space. Could we harness the cosmic radiation and use it as fuel?

Re:How about

[gilleain]

The problem (for biological things, like human beings) is going out of Earth magnetic shield.

For example, from ion irons. Er, iron ions. el reg article.

Re:How about

[grasshoppa]

While you're at it, why not just a star trek-like transporter. Surface to station transporting would solve 90% of the problem!

The space elevator is a gimmick whose sole purpose is to generate budgets. The engineering challenges alone puts this as a pipe dream for at least the next 100 years. Or, to put it another way, we'll have flying cars before we get a space elevator.

Re:How about

[fuzzyfuzzyfungus]

The 'space elevator' is in a funny position. On the one hand, it is much further away, technologically, than just about any other space related project within our solar system. On the other hand, the development of high performance structural materials is something with immediate commercial applications in all sorts of fields, so there is plenty of incentive to make incremental advances in that direction, whether or not that project will ever be feasible. Most other projects are easier; but have fewer short-term payoffs distributed along the path to completion.

Re:How about

[JasterBobaMereel]

Space elevator is not practical yet, we don't have any material to build the cable, I don't know what money is spent on something that we cannot build, except in carbon nanotube research (which should be done anyway), but the rest of the tech involved is very simple and easy

A transporter is probably impossible, a space elevator is just impractical (currently)

Re:How about

[michael_cain]

You properly make the point that all the flashy things that people want to do in space (industry, manned missions to other planets, etc) fail over the same dull, dreary, problem: lifting significant mass to LEO remains prohibitively expensive. Make LEO cheap, and the other things are, if not simple, at least relatively straightforward.

I always think it is worth pointing out that the US made an important decision between the time Apollo was announced and when it placed men on the moon: millions of poor and elderly would receive health care paid for by the government. TTBOMK, manned space programs have all started in countries that did not guarantee full-blown modern health care for their poor and elderly. Originally, the US and the Soviet Union. Today, China and India.

Re:How about

[dbIII]

Physics says there is nothing it can be built from yet.
Try again later.

Re:How about

[mangu]

I always think it is worth pointing out that the US made an important decision between the time Apollo was announced and when it placed men on the moon: millions of poor and elderly would receive health care paid for by the government.

Careful, comrade, you are not being politically correct. Everybody knows that the solution to end the $1.6 trillion deficit is to cut the $700 billion military spending, while leaving the $800 billion health care and $700 billion social security spending intact.

If only the military spending didn't exist, I'm sure some hand waving could take care of the remaining $900 billion deficit. That is, if you forget that nearly half of those $700 billion military spending is manpower cost, which would become unemployment benefits, but let's not consider that detail, just think of a $1.2 trillion deficit if there existed no military spending at all.

Fuck hard data and numbers, dreaming of a socialist utopia is much easier...

Re:How about

[Dishevel]

Silly capitalist pig.
Don't you know that the unemployment problems would be solved the the new 2.6 trillion dollar "Everyone must have a job" program currently being written up in congress.

Re:How about

[Plekto]

Yet the elevator will be possible within the next 40-50 years. It's merely a matter of creating a workable cable at this point. It's a lot like the Chunnel. Well, 50 years ago we couldn't do it. But we knew that we eventually would be able to take it work, because it wasn't impossible - just that we didn't have big enough machinery and tools to make it happen.

Re:How about

[DerekLyons]

You properly make the point that all the flashy things that people want to do in space (industry, manned missions to other planets, etc) fail over the same dull, dreary, problem: lifting significant mass to LEO remains prohibitively expensive.

But what he, you, and the author of the TFA all fail to realize is that expense is not a law of nature.
 
There's nothing intrinsic about space travel that makes it expensive, fuel is cheap, aluminum is cheap, electronics are cheap... What's expensive is building fragile and virtually handcrafted vehicles that require man-hours by the dump truck load to prepare for launch - and then throwing them away after a single use.
 
The costs of space travel will fall significantly when we break out of this broken model. SpaceX and Scaled Composites have shown what can be done with modest investment, but there is yet more that can be done.

Re:How about

[Nyeerrmm]

Reusability has the *potential* to make things cheaper, but its not proven yet.

The shuttle orbiter was re-usable, but the refurbishment process was incredibly expensive. It was also built close to 40 years ago and we've learned a lot since then, so its hard to take it as a valid data point.

SpaceX hasn't demonstrated their re-usability yet. At present, their relative cheapness is based more around vertical integration than reusability right now (and reusing the upper stage is looking less and less likely, but capsule+first stage seems a good start).

And Scaled Composites just isn't in the same league.

This isn't necessarily to disagree or agree, just saying that the jury is still out on that assertion.

Re:How about

[h4rr4r]

Social Security is self funding. That 700 billion comes out of the general budget. See the difference?

Re:How about

[mangu]

You're actually arguing welfare via military service?

No. Just pointing out that (1) even eliminating ALL military spending wouldn't be enough to reduce the deficit by half and (2) a lot of military spending goes to expenses that would have to be met by Medicare/Medicaid/Social Security anyhow.

I was proposing nothing, just pointing out the fact that people who know how to solve all the problems of the world too often cannot do the simple math operations of addition and subtraction.

Re:How about

[Anonymous Coward]

I'm modding you -1 overrated. Not because your answer wasn't useful, but because rather than simply answer a question, you chose to be a dick about it and insult the person asking it first.

Hopefully the next time you feel compelled to toss in a gratuitous insult you'll think about this and find a way to interact without the insults.

I figured I'd be nice and let you know why you were downmodded rather than just do it and leave you wondering.

Re:How about

[Rei]

Apparently neither the pot nor the kettle ever learned to detect sarcasm.

Re:How about

[gnick]

Just to nitpick, the cable is one of two parts of the elevator problem. We'll eventually get this nanotube thing figured out, but we still need something light, strong, and (probably) remotely powered to climb it. We've got to figure out both the robot and his ladder - Neither is a small feat, but neither is impossible.

Re:How about

[Rei]

Everybody knows that the solution to end the $1.6 trillion deficit is to cut the $700 billion military spending, while leaving the $800 billion health care and $700 billion social security spending intact.

The current extremes of our deficit are due to the fact that we're in the greatest recession since the Great Depression. In case you didn't notice. Our average deficits are a fraction as much. And our deficits are as much if not more a problem of continued tax cuts then they are of spending.

That is, if you forget that nearly half of those $700 billion military spending is manpower cost, which would become unemployment benefits

So military spending causes stimulus but other kinds of spending don't? Really? So old people don't buy stuff when they get their social security checks? Doctors and nurses live in caves and burn their cash for warmth?

Re:How about

[Anonymous Coward]

That is kind of what a solar sail does.

Re:How about

[locallyunscene]

Regardless of your priorities, your numbers are wrong. Unless you like to pretend nuclear weapon maintenance, Homeland Security, and veterans' affairs, among others, aren't a part of defense spending:

895B Military/National Security Discretionary
730B Social Security
580B Income Security/Dept of labor
520B Non-Military/Security Discretionary
491B Medicare
297B Medicaid

Defense is the elephant in the room. Reforming all the other programs is noble, but Social Security had a surplus not so long ago and many welfare programs were reformed in the 1990's. The fat to trim is in defense.

Re:How about

[painandgreed]

So, you're telling us that it will be done 20-30 years after we have fusion power?

Re:How about

[CrimsonAvenger]

Social Security is self funding. That 700 billion comes out of the general budget. See the difference?

You're obviously unaware that the Social Security taxes are tossed into the General Fund and spent just like any other tax revenue.

Ditto Medicare taxes.

However, all that aside, if we were to not count SS and Medicare, and discount their tax revenue as well, we'd be talking (for 2010, as an example) $1.069 trillion in revenues and $2.229 trillion in expenditures. Note that in 2010 we had ~$1.036 trillion in non-SS, non-Medicare MANDATORY spending.

Which leaves us ~$33 billion left to fund the entire Federal government. Which means zeroing the entire Federal government except for mandatory programs and the Treasury Department and the Justice Department would still leave us a slight deficit.

Note also that zeroing all MANDATORY spending other than SS, Medicare, and the interest on the National Debt would still require an across the board cut of 34% in order to balance the books.

Food for thought....

Re:How about

[Anonymous Coward]

It's not a dumb idea. It's been suggested before, and the concept is known as a ramscoop.

Re:How about

[swilly]

Ah, but you have to look at the expected increase, not just the current numbers. Social Security is a ponzi scheme, and unless something is done soon it will grow out of control. Health care is also expected to grow (though not by as much). Barring a world war, military spending isn't expected to increase soon.

Cutting defense spending will help in the short term, but will do nothing to prevent our long term budget problems.

Re:How about

[Tablizer]

Could you put a big magnet on the ship to channel the cosmic beams from the sun...

Order it from ACME Rocket Supplies.

Re:How about

[npsimons]

I thought Medicare and Social Security were self-funding? How would it help to cut self-funding projects?

Re:How about

[locallyunscene]

Cutting defense spending will help in the short term, but will do nothing to prevent our long term budget problems.

We can't prevent our budget problems; we have budget problems, and we're talking about how we can cut spending. There's no reason not to go after the largest least reformed area of spending other than pure stubbornness. Our Empire costs more than we can afford.

Re:How about

[chgros]

You mean like a solar sail?

Re:How about

[tnk1]

So military spending causes stimulus but other kinds of spending don't? Really? So old people don't buy stuff when they get their social security checks? Doctors and nurses live in caves and burn their cash for warmth?

Caring for the elderly is desirable, but it's maintenance. You don't stimulate an economy by doing maintenance, especially on people, unless that maintenance keeps them productive. Otherwise it is all cost. The doctors and nurses are just what is needed for the maintenance. You can't actually grow an economy in an absolute sense by doing maintenance.

Defense spending has it's share of maintenance too, of course, but it is also substantially invested in all sorts of research. The Internet, for instance, is one example of Defense spending paying off because it increased knowledge.

On the other hand, there is medical research, which can improve an economy, but it does so only if it keeps humans productive. Any research that merely keeps humans alive in an unproductive state just increases costs. In the purest sense of economy, if you eventually cost more to keep yourself alive in your unproductive years than you were able to produce in the years you were productive, you are a drain on an economy. Such a drain can be justified by the high value of human life itself, but that value does not have any economic effect.

Eventually if you have more drains than than inputs into your economy, it's going to collapse. If you have overdrawn your account via borrowing money to keep yourself alive, you have condemned your children to not only not have the option, but also to have a worse life because they also have your interest to pay off.

Re:How about

[Risen888]

Careful, comrade, you are not being politically correct. Everybody knows that the solution to end the $1.6 trillion deficit is to cut the $700 billion military spending, while leaving the $800 billion health care and $700 billion social security spending intact.

Maybe that's what everyone knows, but maybe everyone doesn't know that if our government hadn't continually raided the Social Security fund for generations (for things like debt service and the military, among others) that shit would be paying for itself.

Re:How about

[GeordieMac]

yup, excellent point. Although another poster correctly stated the similarity with solar sails its also close in concept to the Mini-Magnetospheric Plasma Propulsion concept or M2P2.

Re:How about

[Plekto]

Correct. It's like saying that we couldn't see planets around other stars. Well, 50 years ago we couldn't. But it was easily known, even then, that what we needed was a mirror that was large enough - and not much else. (of course making it was a tad harder, of course)

Re:How about

[repapetilto]

In my book, you also failed to actually answer the question. The answer is: There are not enough cosmic rays to be worth the difficulty of harvesting them. Yes, this is implied by your answer, but why you didn't just outright state it is beyond me. Similarly, you act like cosmic ray density is common knowledge, most people have no use for this information in their every day life and so will forget it even if they learned it in 5th grade. That you expect everyone to know this detail is definitely strange. For example, can you name all the major organelles off the top of your head? This was also learned in elementary school.

Re:How about

[Rei]

No, what is hard for *you* to understand that no matter where you cut spending, it's going to cut jobs? Military spending is not special in that regard. So if your goal is to cut spending, tough -- you're going to kill jobs. Deficit spending is stimulative (in the short term).

Re:How about

[WolfWithoutAClause]

How about no?

a) no carbon nanotubes = you don't go

b) Van Allen belts = really nasty radiation that the beanstalk would have to go right through (the shielding is too heavy until you can launch about a thousand tonnes, which would be horrifically expensive to build). Think: continuous dental x-ray for a day or two.

Re:How about

[ResidentSourcerer]

Heavy sigh.

Don't know if you are serious, but I'm going to pretend that you are:

1. Cosmic beams. No such animal.

2. Magnetic fields interact with other magnetic fields. Since an electron moving relative a magnetic field has a mag field of it's own, we can use a moving magnetic field to generate power or to convert moving electrons to mechanical motion.

3. The magnetic field of the earth isn't very strong -- about half a gauss. I haven't seen a way to extract energy out of it.

4. In general: There is no free lunch. The energy has to come from somewhere. Compare to gravity: You can get energy out of a gravitational field by lowering mass into the field. this is how a hydro electric dam works. If you think you can beat the system, make a table top prototype using small magnets.

Spaceflight right now is inefficient. The only way we move is by throwing mass the other way very fast, and depending on conservation of momentum.
Mv = mV Throwing a kilogram backword at 2000 m/sec moves your 500 kg spaceship forward at 4 m/sec

You can do better by throwing it faster. but the specific impulse of current chemistry imposes limits. Also: chucking the mass with twice the velocity will get twice the velocity change for the space ship, but takes 4 times the energy.

The beanstalk idea is doable: We have the science for it, but not the technology. (Carbon fiber nanotubes have sufficient strength. We don't know how to make them in the length and quantity required.) It will require developing deep space infrastructure -- lots of the material is easiest (lowest energy) to get from the asteroid belt.

And we need to get our house in order. A bean stalk is a wonderful terrorist target. Cutting the stalk at synchronous orbit would have a similar effect to dropping a hydrogen bomb every 5 miles along the entire equator.

Travel between planets in reasonable times is a bit more practical:

1. You don't have to throw large amounts of mass the other way just to fight gravity. So you can use more energy to accelerate less mass. Since you are out in the sunshine, you don't have to use chemistry to provide the energy.

2. Because the interplanetary void has a low density plasma, with clever design, you can use a ring of current to interact with it, getting small but steady thrust, using the mass of the plasma instead of mass you bring with you.

3. There is also the possibility of sailing on the solar wind.

None of these are current technologies, but all of them are reasonable developments of currently known science.

I'm bullish on spaceflight, although in terms of practical economy, the moon, the asteroids (metal, some carbon) and Saturn's rings (water) are much better targets than Mars.

Re:How about

[LWATCDR]

I did answer that there was not enough. You may be correct but it seems pretty plane to me that if there was enough cosmic rays to use as propulsion that almost nothing including most electronics would last very long out there. I did agree with you that my comment did not match my intention but then if you are on the internet you do have access to that knowledge. As to your organelle question I would ask you which type of cell? And no that was not Elementary school that was Jr. High. And yes I will try to not be so critical in the future. You are correct that it was a bit harsh of me. My wife keeps trying to remind me that not everyone has the same memory as I do.

Re:How about

[uninformedLuddite]

It might get a few Republicans off of Prozac

Re:How about

[repapetilto]

All is cool then.

A sense of scale

[elrous0]

Most people have no real appreciation of the scale involved in psace travel. As daunting as our own solar system is, even that pales in comparison to the scales involved in traveling to other solar systems. Currently it takes us about 9 years for a probe to reach Pluto. When I ask people to guess how long it would take that same probe to reach the nearest solar system (a mere 4.2 light years away), people's estimates are usually comically far off.

120,000 years is the correct answer. Most people guess between 100-1000. That's why people think it is plausible for mankind to colonize space. They don't appreciate the scale we're talking about.

Re:A sense of scale

[avgjoe62]

TFA isn't talking about interstellar flight. It's talking about a human flight to Mars. And it ignores so much that I have to believe this was posted to /. just to generate page hits on the article.

The article takes the idea that a human flight to Mars has to follow some model that hasn't seriously been considered for nearly a decade. The all-in-one, carry-our-own-fuel model that got us to the moon cannot be applied to Mars. The author is right in that. But nowhere does the article mention the possibility of sending unmanned flights out first to land and prepare a site for later human exploration. If we can send our smart robots there to create a habitat and refine fuel on the surface of Mars, most of the problems mentioned in the article disappear.

I find it ironic that the article mentions Moore's Law and the growth of human knowledge, then does not think to apply any creative thinking to the problem, just a tired old story about how difficult and expensive it would be to launch the all-in-one type of craft that got us to the Moon. Did the author not think we could use some of that processing power and knowledge to come up with new solutions using tried and tested technologies?

Re:A sense of scale

[ShadyG]

What's the point of a scale, when there's no gravity?

Re:A sense of scale

[Runaway1956]

Just a hint. "Star travel" and "space colonization" aren't synonymous. We could, with some determination, build a colony on the moon, with existing technology. Or, if not a real colony, then at least a research station. As time passed, our technology could grow to better support that colony, and at the same time, the colony could grow more self sufficient.

Now, star travel is a whole different ballgame. Compare colonizing our solar system, to a baby learning how to crawl, then to walk. The baby is NOT going to mysteriously appear in another city around the world just because he has begun to walk.

I say, let's start crawling, and build that moon colony.

Re:A sense of scale

[elrous0]

It's based on the speed of the New Horizons probe. And yes, you could build a vehicle that was faster. But it would still take a VERY long time to travel 4.2 light years, and likely wouldn't be able to stop once it got there (assuming that you had kind of precision you would need in navigational calculations to even get there).

Re:A sense of scale

[Abstrackt]

So uhh, tell me where this "correct" answer comes from.

Probably the assumption that the probe is being propelled by today's technology rather than tomorrow's.

Re:A sense of scale

[elrous0]

Well, that's rather the point. Until you have better propulsion technology (MUCH better), it's really just a dream. Da Vinci could dream of an airplane, but until the internal combustion engine came along it wasn't going to happen.

Re:A sense of scale

[Anonymous Coward]

I've always known it would take a vast amount of resources to reach a nearby star. Looking at an illustration of the Daedalus next to the Empire State Building which it dwarfs showed it better than I could even explain. Just to reach another star within a lifetime would take more resources than have been spent on all space exploration in the last 100 years combined and I'm including all satellites and military projects of every country in the world. Just feeding and providing for the current population of the world for the next hundred years is an impossible task, we've been exceeding our resources since the early 80s. We simply don't have the resources to send a single probe let alone get one or more live humans to another star. We had a narrow window I think to establish ourselves in space but that window has probably closed. To strike out into space we need self sustaining colonies. To do this would take many hundreds of times what was invested on the space station and that will never happen. It's easy to say technology can solve the problem but that's like saying we'll solve fusion power. My favorite laughable technology is the beloved warp drive. To cause that kind of distortion of space would take more power than a star generates. We have trouble powering electric cars. At our current rate of development we aren't talking hundreds of years but millions of years off and we don't have a million years of resources. A decade of cell phones and the like have made a major dent in the supply of rare earth metals. What are the odds of our current industrial technologies lasting a 100 years, a 1,000 years, a million years? It takes the will as a people and resources. We have neither.

Re:A sense of scale

[khallow]

120,000 years is the correct answer.

If our goal is to send a probe to another solar system (without stopping) using current technology, we can do that in much less than 120k years. Ion propulsion with a large number of RTGs and a huge mass fraction, can probably reach 0.01. And if we launch a lot of vehicles, all but one which carry propellant and transfer propellant between vehicles, we probably can improve that number to several percent of the speed of light (fly out till half of everyone's propellant is used, then half transfer their remaining propellant to another half and we repeat the process, till there is only one vehicle with the payload left).

I think it reasonable that we can get a vehicle to fly by Alpha Centauri inside of a couple of centuries using current technology.

Re:A sense of scale

[JasterBobaMereel]

Space is 62 miles away, it's only 4 days to the moon .... space is small for some destiations ...

Re:A sense of scale

[Urkki]

That's why people think it is plausible for mankind to colonize space. They don't appreciate the scale we're talking about.

Us thinking about travelling to other star systems is like a crippled caveman thinking about flying like a bird by jumping of a cliff.

Now, on Earth environment with our laws of physics, we overcame that with technology (like airplanes). Wether we can overcome that with space traver remains to be seen. It's way too early to make a guess one way or another, except that if it is physically possible, and if we don't kill ourselves first, "we" will do it, for whatever meaning of "we" that might apply in the future.

Re:A sense of scale

[Anonymous Coward]

It may not be plausible to colonize space, and we may be confused about how fast New Horizons flies, and most people probably do not have an intuitive appreciation of the scale involved. I don't think I do. But, at least some experts that we might take seriously thought we could get to Proxima Centauri in around 50 years (http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29#Interstellar_missions). So I don't think it's the travel time that's the problem. It's more like it's not worth 0.1 US annual GNP to anyone to try.

Unfortunately, since it doesn't seem to be worth 0.0001 GNP to anyone to continue useful research in that direction, space travel is not getting gigantically cheaper or faster anytime soon.

Re:A sense of scale

[SlippyToad]

Most people have no real appreciation of the scale involved in psace travel. As daunting as our own solar system is, even that pales in comparison to the scales involved in traveling to other solar systems. Currently it takes us about 9 years for a probe to reach Pluto. When I ask people to guess how long it would take that same probe to reach the nearest solar system (a mere 4.2 light years away), people's estimates are usually comically far off.

120,000 years is the correct answer. Most people guess between 100-1000. That's why people think it is plausible for mankind to colonize space. They don't appreciate the scale we're talking about.

That's with current technology. So basically, it's too hard so let's not try.

Jesus. The human race is too busy farting into our own couch to even think of getting our fat asses off it and trying something new.

Re:A sense of scale

[defaria]

Maybe most people equate "colonize space" with "colonize the solar system" which, last time I checked, is also "space"!

Re:A sense of scale

[grumbel]

When I ask people to guess how long it would take that same probe to reach the nearest solar system (a mere 4.2 light years away), people's estimates are usually comically far off.

Going to the nearest star would take around 50-100 years with nuclear propulsion, which considering that our Voyager probes are already traveling around for 30 years doesn't look that crazy as far as time is concerned. Comparison with our current non-nuclear driven probes are misleading, as nobody would be stupid enough to launch one of those to the next star. Our current probes are slow because thats the cheapest way to them, not because they are at the limits of our technological capabilities.

While there are certainly physical limits to space travel, none of those are really a stopping block for getting to another star or even colonizing another planet, it might just take a while and cost a ton of money.

Re:A sense of scale

[hedwards]

TFA isn't talking about interstellar flight. It's talking about a human flight to Mars. And it ignores so much that I have to believe this was posted to /. just to generate page hits on the article.

Well, the jokes on them because we don't RTFA around here.

Re:A sense of scale

[Skarecrow77]

There is a second page to the article where the author brings up mining Mars. He says it would be impractical.

Yes, and he says it in perfect hand-waving "doesn't work with my argument so I'm going to ignore it" fashion.

His contention is that the the quality of the resulting fuels and resources would be low. Why? Where is his data? Last I read on the subject, when we test out the same technologies and processes on earth that we'd be sending to mars, the results are will within tolerances. It's not like the chemical equations and processes involved haven't been around since we were using gaslights.

On top of that, it's not really that major a concern. if we can currently send a probe to mars that can detect miniscule trace elements in martian soil, we can damn well smack a sensor on the side of those rapidly filling methane and water tanks on mars to send us back a signal on their purity. if for some unforseen reason the process that works on hydrogen and carbon dioxide here doesn't work right there, we analyze the data, figure out why, and then send up another converter to do the job right.

You wait until the tank is full of good stuff before sending the people.

Re:A sense of scale

[Skarecrow77]

an Ion drive (which I'm sure you know we have today) firing constantly (which they can do) will eventually build up pretty damn absurd speeds given enough time... and if you're traveling between stars, time is something you have in abundance.

Slowing down though, that's another matter.

Re:A sense of scale

[Chrontius]

Most people have no real appreciation of the scale involved in psace travel. As daunting as our own solar system is, even that pales in comparison to the scales involved in traveling to other solar systems. Currently it takes us about 9 years for a probe to reach Pluto. When I ask people to guess how long it would take that same probe to reach the nearest solar system (a mere 4.2 light years away), people's estimates are usually comically far off.

120,000 years is the correct answer. Most people guess between 100-1000. That's why people think it is plausible for mankind to colonize space. They don't appreciate the scale we're talking about.

Project Longshot was talking about getting a probe to Proxima Centauri and returning data within 40 years. On the other hand, Longshot was an atomic robot designed to reach low relativistic speed, autonomously survey the star system, and launch space probes to further investigate anything the computer considers interesting.

Re:A sense of scale

[Chrontius]

Magnetic solar sail braking is stupendously energy - and propellant - efficient, making it much cheaper to brake than accelerate. This also helps your flying-fuel-pyramid problem.

Either Longshot or Daedalus was supposed to enter orbit around Barnard's star (the other was indeed a flyby), meaning that stopping at the target system is in fact feasible.

Re:A sense of scale

[Chrontius]

Both projects Daedalus and Longshot used a fusion engine in order to do something an awful lot like that. Daedalus used inertial fusion for main power and thrust, Longshot used a fission plant to power the fusion torch and all kinds of sensors when they get there. Not to mention using a 45-meter engine bell as a radio dish to return the results to Earth.

Re:A sense of scale

[Chrontius]

Those rare earths aren't exactly rare; they're just really hard to process.

I look forward to nanotech recycling and making expensive and scarce raw materials cheap and common.

Re:A sense of scale

[Al Al Cool J]

The reason that mankind is unlikely to colonize space is that most alien technological civilizations in the galaxy will have already beaten us to it. People who talk about the scale of distance in interstellar travel often don't appreciate the scales of time that existing civilizations would have had to work with. Even at just 1% the speed of light, you can colonize the entire galaxy in less than 10 million years. That's nothing when you consider that another civilization could easily be up to a half-billion years older than us.

Re:A sense of scale

[phantomfive]

Not only that, the energy required is tremendous. This is not likely to change even if you invent something like teleportation. Getting to Alpha Centauri would require at least 100 times the energy output of the entire world. Think about that. We will solve all stellar energy crisises before that.

Re:A sense of scale

[FridayBob]

Here's a better way to look at the distance to Proxima Centauri: if the Milky Way galaxy is scaled down so that the distance from the Earth to the Sun (usually about 150 million km) is reduced to only 1 mm, then Pluto would be 4 cm from the Sun, but our nearest stellar neighbor would still be 267 m away. Oh, and the Oort Cloud would (theoretically) be 10 m in radius, the diameter of the Milky Way galaxy would be 6,327 km and the Andromeda galaxy would be 139,200 km from us.

IMO, in the best possible case it may be possible for our descendants to colonize most of our own solar system. However, considering the vast distances involved, I view it as unlikely that we will ever attempt interstellar travel... at least not on a regular basis and barring the invention of some revolutionary propulsion technology, such as a "warp engine".

What's more, even if we ever were to develop the capability of accelerating a large enough ship up to a significant fraction of the speed of light within a relatively short span of time, then we would still be faced with the problem of abrasion due to interstellar gas and dust. At those speeds, every speck of dust hitting the front of such a space ship would inflict an inordinate amount of damage. Therefore, another one of Gene Roddenberry's inventions would be needed: the deflector dish.

Face it: this universe just wasn't made for tourism.

Re:A sense of scale

[TastyCakes]

Actually, most of humanity still lives in squalor and poverty. My view on space colonization is this: in the long term, absolutely it is a great idea. It is the only way humanity can ensure its continued survival and be more than an infinitesimal blip in the history of the universe.
In the short term, I see no way to justify the trillions of dollars required to become a "space faring civilization" while so much of the human population is having trouble keeping body and soul together. Once we have stabilized our population, sorted our nations states out politically to at least provide basic necessities and freedoms to the bulk of people and eliminate the threat of war hanging over so many heads, then I think we, as a species, are ready to start approaching such transcendental goals as colonizing other worlds.
Humans haven't been around that long in the big scheme of things. Our relatively short lifespans make us impatient and eager to expand quickly. But any meaningful off-world colonization will be the work of generations and will probably not see significant returns for centuries (I'm talking about inter-stellar colonization being the ultimate goal, the only type that I think is really worth a damn in the overall scheme). In my opinion, it makes no sense to bite off such a huge challenge when we live in such a precipitous situation at home. So by all means, lets continue to send probes to assess the universe. But human exploration is almost certain to be a less effective use of money, and is favourable only from a PR/political perspective.

Re:A sense of scale

[kirtu]

That's true but if we made it a goal then we could launch interstellar missions within 50 years with velocities of 1/10th the speed of light. So it's a step forward if we decide to take it. More to the point, we could within 50 years easily travel at 1/100th the speed of light and that opens up the solar system and the closest parts of the Oort Cloud.

Re:A sense of scale

[kirtu]

Most people have no real appreciation of the scale involved in psace travel. As daunting as our own solar system is, even that pales in comparison to the scales involved in traveling to other solar systems. Currently it takes us about 9 years for a probe to reach Pluto. When I ask people to guess how long it would take that same probe to reach the nearest solar system (a mere 4.2 light years away), people's estimates are usually comically far off.

120,000 years is the correct answer. Most people guess between 100-1000. That's why people think it is plausible for mankind to colonize space. They don't appreciate the scale we're talking about.

Sure - powers of ten are still difficult even for people who think of themselves as technologically sophisticated. The solution is better education as always.

Re:A sense of scale

[kirtu]

No - we (humanity) could actually put bases on the moon within a decade if we decided to do so. The same with Mars. For that matter it's the same with Earth crossing asteriods but with those we have a real problem - they don't have resources to sustain life whereas the moon has enough and Mars certainly can support thousands, perhaps millions of people. So to begin with the moon and Mars we are set already.

Re:A sense of scale

[selex]

There is a park I go for walks all the time. I notice the first time last week (when I decided to walk on the other side of the creek) and there was a Solar System Walk there. Its a bunch of pedestals with information about the Sun and each planet, and then each pedestal is placed approximately to scale per the park size to their distance in the solar system. The Sun to Mercury roughly 10 feet, Mercury to Venus 15, Venus to Earth 15, Mars is another few feet, and then Jupiter is a good 70 more feet and sits in the middle of the field. From the Sun to the beginning of the line of trees is 2000 ft. Saturn is past that on top of a hill. Neptune is the other end of the damn forest, Uranus is in a field near the damn highway, and Pluto (yes its an old walk) is past that. The direct line distance is a 1 mile, which doesn't account for the vertical distance or the path winding.

I did not appreciate the distance until then, and I said screw it I'm staying right here. I thought flying to Florida was mind numbingly dull...hey look guys more vastness of space! At least the walk gives me trees and geese fights.

Selex

Um, ok...

[pushing-robot]

...But that's the thing about current technologies: They inevitably insist on becoming obsolete technologies.

Re:Um, ok...

[thisnamestoolong]

Nah, I remember one time this guy told me that 640K ought to be enough for anybody, and that is certainly still true today.

Re:Um, ok...

[Charliemopps]

But that doesn't get around the laws of physics.

We will NEVER travel faster than the speed of light.
We will NEVER create a wormhole a human can pass through.
We will NEVER create teleportation that works on a human.
Traveling at a very signifigant fraction of the speed of light, say 90%, would be very difficult but maybe not impossible. That's yet to be seen.

Does this mean space travel is impossible? No... it will just take a very very long time.
The laws of physics as we understand them do not prevent the invention of a technology that would be like the classic SciFi Hypersleep. We could also colonize an asteroid and let the crews great grandchildren be the ones to visit the new solar system. It's all possible, we just wont be zipping around like StarTrek.

Re:Um, ok...

[countertrolling]

We will NEVER travel faster than the speed of light...

Man will never fly...much less faster than sound...

Re:Um, ok...

[mikael_j]

We will NEVER travel faster than the speed of light.

That depends on your definition of "faster than the speed of light". There are some theoretical "tricks" like an Alcubierre drive that would allow us to travel "faster than light".

Of course, the Alcubierre drive has a ton of issues that would make it pretty much useless but I just don't like the naysayer attitude of those opposed to manned spaceflight ("We'll never go to Mars!", "Manned space travel isa dead end!", "We'll never leave the solar system!", "We should just stay in our gravity well because it does not make sense financially to send people to LEO or further!"...)

Re:Um, ok...

[w_dragon]

Funny you mention Star Trek. The physics they use to go FTL don't break relativity. They may not work by modern physics, but the general idea was that by manipulating gravity you can curve space around the ship to cause you to change position in space faster than light without actually having to move faster than light. From my understanding, at the time it wasn't impossible given the limitations of our understanding of gravity.

Re:Um, ok...

[khallow]

Does the timescale of technological advance change the debate, at all?

Why are you expecting any answer other than "yes"?

duh..

[Anonymous Coward]

Who here thought we could build a starship "with current technologies"?

Re:duh..

[ThunderBird89]

I did.

How about a generation ship, there are perfectly workable designs for that. Granted, it's not the most comfortable way to travel, knowing that by the time you get to your destination, only your great-great-great-great-great-great-great-great-great-great-grandchildren will be alive, and even the tech you use will belong in a museum.

But it's ONE way to do it...

Re:duh..

[Runaway1956]

TAANSTAFL

Robert A. Heinlein

Everything costs. Even if you do away with all of the world's currency, things will still cost. You will merely be stating the costs in another manner, ie, "manhours", or "credits", or - whatever.

Re:duh..

[MBGMorden]

Building the ship might be possible. That same ship running for tens of thousands of years? Not yet. It's hard these days to keep anything running more than 30-40 years, and that's with an infinite supply of replacement parts. Having a ship run for thousands of years, even with a crew constantly repairing it, is unlikely to work with the durability of current technology. Maybe in the future, but not now. Realistically we should be looking at the close by stuff: Mars, asteroids, and the moons of the gas giants. The technology we develop getting there will greatly help any future endeavors.

Re:duh..

[biryokumaru]

That's not nearly enough generations. It'd be more like 6,000 greats. How are you going to bring enough food for all those people? How are you going to provide capacity for sufficient genetic diversity to prevent them from becoming as inbred as the royal family?

I say we don't send anything to another solar system until we have a high level of confidence that ships leaving after it won't get there first.

Re:duh..

[chthon]

TANSTAAFL!

There Ain't No Such Thing As A Free Lunch!

Re:duh..

[Runaway1956]

Thank you, Sir. I could try to play it cool, and tell you that I misspelled it just to see who was awake - but, what's the use? I screwed it up. Ehhh. If that's the only thing I screw up today, it will be an unbelievably good day!

Re:duh..

[beschra]

How are you going to bring enough food for all those people?

Soylent green

Re:duh..

[GodfatherofSoul]

That was a human settlement in the RPG 2300AD. It was half occupied with the bad-guy aliens.

Re:duh..

[Risen888]

How about a generation ship, there are perfectly workable designs for that.

Name two.

"at least with current technologies"

[webrunner]

So basically something we haven't invented the technology for is impossible until the technology is invented.

I'm so shocked.

Re:"at least with current technologies"

[koolfy]

Captain Obvious is SO shitting bricks when he reads this.

at least with current technologies..

[js3]

wow really? Even a monkey could have figured that out.

Re:at least with current technologies..

[williamhb]

wow really? Even a monkey could have figured that out.

Doh! So that's why I haven't seen any monkeys trying to build space rockets! I knew there had to be an explanation in there somewhere.

Re:at least with current technologies..

[grub]

They're too busy typing.

Re:at least with current technologies..

[sjames]

So THAT's why I've never seen a bunch of monkeys wasting their time building a colony rocket to Mars!

Forget air travel.

[Issarlk]

There is only so much power you can get out of a locomotive, and it's never gonna make one fly in the sky due to the considerable weight of a steam engine.

Re:Forget air travel.

[Anonymous Coward]

You, sir, win this round. Eloquently put!

Re:Forget air travel.

[Anonymous Coward]

Doc Brown begs to differ:
http://eightiesology.files.wordpress.com/2009/03/back_to_the_future_part_iii_large_18.jpg

Re:Forget air travel.

[ciderbrew]

Insightful just hit 11.

Re:Forget air travel.

[Dunega]

Wouldn't that be 6 here? (5 point mod system) :)

Re:Forget air travel.

[ciderbrew]

[pause] These go to eleven.

Re:Forget air travel.

[Yossarian45793]

The Chinese have a saying: "Man who says it cannot be done should get out of the way of man who is doing it."

Re:Forget air travel.

[dominious]

Dude, you are on the wrong thread... and time.

I didn't know /. has a time portal. When am I?!

Re:Forget air travel.

[DryGrian]

I thought that saying was from novelty coffee cup manufacturers, not the Chinese.

RTFA

[wjousts]

Great summary. All of one sentence that tells us nothing, not even what the source is. I really don't understand what Slashdot wants for a submission so I've mostly stopped bothering.

Re:RTFA

[camperdave]

Great summary. All of one sentence that tells us nothing, not even what the source is. I really don't understand what Slashdot wants for a submission so I've mostly stopped bothering.

Find an article on one of Slashdot's sister sites and submit that.

Re:RTFA

[countertrolling]

The RSS leaked. Submission process is being automated to pick out popular stories, so the uniqueness of Slashdot is long gone.

Errr... Chemistry?

[Warwick Allison]

Plenty of interstellar ship concepts propose nuclear power and are therefore outside the "titanic" power of mere chemistry.

Re:Errr... Chemistry?

[Culture20]

Nuclear!? What about tsunamis?

Re:Errr... Chemistry?

[thisnamestoolong]

This. My personal belief upon looking at human history is that if something is not prohibited by the laws of physics and a large enough number of people want to do it, then we eventually figure out how to do it. Case in point -- just imagine telling someone in 1950 that we would put a man on the moon. Or go back to 1990 with a modern smartphone. Just because something is difficult and not possible with current technology only means that we need to get our asses in gear and find the technology to do it.

Re:Errr... Chemistry?

[Jonathan_S]

Nuclear!? What about tsunamis?

If you converted that power into a weapon would you have a wave motion gun?

Von Braun does not agree

[Anonymous Coward]

An Orion engine could get you to the stars in 40 years, Mars in a few weeks. A solar sail can accelerate you almost up to the speed of light and travel to the ends of the universe. It's politics and economics that are major barriers to space travel, not physics and chemistry.

Re:Von Braun does not agree

[Wonko the Sane]

But you see project Orion dates back to the 1960s and was never implemented so it doesn't count as "current technology". Space travel is only practical with past technology. Why does this situation remind me of the decline of the empire in the Foundation series?

Re:Von Braun does not agree

[Chrisq]

Wow, my next car will be a Mitsubishi.

Re:Von Braun does not agree

[jandrese]

Just out of curiosity, have you ever tried to do the math to figure out how long it would take a solar sail to propel you "almost up to the speed of light", or how long it would take to reach the nearest star using one?

Re:Von Braun does not agree

[the_womble]

Quite a lot of what is happening at the moment reminds me of the Foundation series or the decline of the Roman Empire - slowing technological advances, loss of interest in science, weakening governance.....

Roman civilisation never disappeared entirely. The Eastern Roman lasted until after the Renaissance started.

Re:Von Braun does not agree

[SETIGuy]

Why does this situation remind me of the decline of the empire in the Foundation series?

Perhaps because we happen to be witnessing the decline and fall on an empire?

Forget it? I don't think so!

[Scholasticus]

Remember, any kind of space travel was thought impossible at one time ... until the multi-stage rocket was invented. We need more creative thinking and less of this overly pessimistic nay-saying.

... at least with current technologies

[Anonymous Coward]

Of course chemical rockets are very limited, in fact they barely work at all to get to other planets (gravitational assists are needed, etc.). But with ion drives, nuclear rockets and other technologies (see http://en.wikipedia.org/wiki/Spacecraft_propulsion#Table_of_methods), some of which have already been tested and used, other technologies still under development, and others in the further future, such missions will become far easier and more routine. These are not limited by the energy you can get from chemical reactions

Forget Rockets. Stargate

[Anonymous Coward]

Forget rockets, we'll discover how to use Stargate like technology way before cracking warp drive and long term space dwelling.

You suck.

[The Bringer]

This is the most depressing submission of the day. I could rant and rave about how humanity will overcome the barriers put before us, or perhaps about the evolution of technology. I could go out on a limb and say that all of the world's physicists are wrong, and that faster than light travel is indeed a possibility. But, I think I will take one from the page of the submitter and keep this concise: You suck.

Re:Space Travel is a silly idea

[wjousts]

What would we need to find out there? Why would anyone want to be there?

Because at some point the sun will turn into a red giant and swallow the earth whole. This will obliterate humanity and every single thing we've ever done. We will be completely and irreversibility erased from the universe.

A lot of people find that thought rather uncomfortable.

1850 has send you a telegram

[kikito]

According to Physics and Chemistry self-propelled chariots are impossible STOP self-propelled flying vehicles are a fool's errand STOP Internet is that little net inside some pieces of underwear STOP.

Re:1850 has send you a telegram

[ElectricTurtle]

There is an actual quote from the 19th century that fits as well or better:

"What, sir, would you make a ship sail against the wind and currents by lighting a bonfire under her deck? I pray you, excuse me, I have not the time to listen to such nonsense."

Napoleon Bonaparte, when told of Robert Fulton's steamboat.

Re:1850 has send you a telegram

[ArmchairGeneral]

Every time I see that quote now, I hear Leonard Nimoy's voice narrating it.

Re:1850 has send you a telegram

[ElectricTurtle]

Me too. Even if only by a few quotes, Sid Meier and co. have really brought the humanities to the masses. I just hope a few people will be impressed enough to tackle the sources from which they are extracted. Works like the Nichomachean Ethics, The Prince, the Art of War, etc. have transcendent value far beyond a few good one liners.

Re:1850 has send you a telegram

[mr_mischief]

Here are a couple of quotes from the 20th that fit rather well, too.

That Professor Goddard with his "chair" in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action and reaction, and of the need to have something better than a vacuum against which to react—to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.

New York Times, January 13, 1920

Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th Century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.

New York Times, July 17, 1969 (the day after the launch of Apollo 11)

Wikipedia article on Goddard

Re:1850 has send you a telegram

[DryGrian]

I like that one, way fresher than that old 640k line. :-)

Huh?

[Anonymous Coward]

Premise: You cannot go into deep space because chemical rockets have insufficient energy to get you there.

Recommendation: Therefore you should only send people into space one way.

Real purpose of article: For the Author to brag that he is wealthy enough to book a flight on Virgin Galactic.

Dumb article. Does not mention carbon freeze.

[140Mandak262Jamuna]

Folks, save yourself some time and skip reading the article. It does not mention carbon freeze, or mini black hole based ionic propulsion, jumping into hyperspace, worm holes, tachyon particles, not even those ray blasting cannons that curiously recoil like a second world was naval gun, phasors that could be set to stun, or transporters.

OK, OK I concede that stuff like flue powder, aparating and portals seem improbable, just to show that I am not unreasonable, and am considering only proven viable technologies.

Pretty bad article

[Clsid]

That article is a joke. It doesn't even take into consideration very public recent development like http://www.fastcompany.com/1744745/russia-us-plan-a-nuclear-powered-space-rocket-should-we-worry

Plus Russia announced it created a nuclear reactor that was capable of being transported and used in a rocket some months ago. Plus the sun is an infinite source of energy when you are in space, which should make whatever fuel you are going to use last longer.

Re:Pretty bad article

[ciderbrew]

We all know the sun is not a infinite source of energy. But I get 300 minutes of talk time on my phone a month, which may as well be infinite.
Conclusion: Infinite, even when very very very small, is very very big.

Re:Pretty bad article

[kaiser423]

Plus the sun is an infinite source of energy when you are in space, which should make whatever fuel you are going to use last longer.

Eh, to a certain extent. Look at the Juno spacecraft. It's solar arrays are 650 square feet. Similar in size to those on the ISS, but on a planetary probe. Why so big? Well, they'll produce >15,0000W in Earth orbit, but by the time that the spacecraft hits Jupiter (which, in interstellar terms isn't all that far away), they'll produce ~450W.

That's a big change. You can't really rely on solar power as a main energy source if you're heading very far out. Mars isn't too bad, but if you want to start exploring out further, in some cases solar panels actually cost you because they'll provide so little power, but take up a good chunk of launch weight that could be used for other fuel sources.

Its hard to tell - but

[Chrisq]

Its hard to tell because the article contains no facts or assumptions, but I think it is working on the assumption that the Mars space craft and all fuel will have to be lifted from the earth in one go. If we assemble the craft in earth orbit then fuel it in multiple trips the energy requirements to get it to Mars orbit will be much lower. At that point it can again use a "lander" vehicle to take the astronauts and equipment to the surface, a lot of which can be left behind for the return trip (as was done with the moonshots).

Re:Space Travel is a silly idea

[muffen]

People are stupid -- Dr. House

Wow, uh, I never thought of that!

[bmo]

I mean, really, in 1969 we magically had all the tech to get to the Moon and back, it's not like we had to invent anything. /sarcasm

People get paid to write this crap?

--
BMO

Re:Space Travel is a silly idea

[cyn1c77]

Most probably, space travel is not worth the energy required for propulsion. What would we need to find out there? Why would anyone want to be there? For all the answers you might have come up with, I think virtual realities are a solution that is much cheaper to deploy and maintain.

Using the same logic, I would argue that most humans are not worth the resources required to sustain them. And if we spent less resources supporting those humans, we would have more resources for space travel.

**CRACK*** *POP* *CRUNCH*

[tropgeek]

NOM NOM, Nothing wakes you up in the morning, like crushing the hope of science dreamers everywhere.
To quote Einstein: "Whoever undertakes to set himself up as judge in the field of truth and knowledge is shipwrecked by the laughter of the Gods."

Auguste Comte Fallacy

[Epeeist]

Of all objects, the planets are those which appear to us under the least varied aspect. We see how we may determine their forms, their distances, their bulk, and their motions, but we can never known anything of their chemical or mineralogical structure; and, much less, that of organized beings living on their surface

Said by Comte in 1842. There is a difference between unknown and unknowable.

Impossible...

[kubernet3s]

at least with current technologogies? Duh. If we could do it, we would have. No one seriously believes the main obstacle to a Mars mission is the liberal agenda or the freemasons or anything, right?

Re:Impossible...

[JockTroll]

Correct. Did we play in the same football team?

Re:Impossible...

[Tanuki64]

Build me a perpetuum mobile.

Re:Impossible...

[Solensean]

Build me a perpetuum mobile.

Are you saying that because my metaphor is factually incorrect, you can compare not being able to defy the laws of thermodynamics and not being able to travel through space, a thing that we simply don't know how to do (efficiently) yet?

Re:Impossible...

[Tanuki64]

It simply might be that there is no 'yet'. Maybe there simply is no way to do it efficiently with the existing laws of nature. The perpetuum mobile is just an example that there are things which will always be impossible regardless of our technological advancements. Maybe space travel is as impossible just not as obvious?
 

Re:Impossible...

[Solensean]

It simply might be that there is no 'yet'. Maybe there simply is no way to do it efficiently with the existing laws of nature. The perpetuum mobile is just an example that there are things which will always be impossible regardless of our technological advancements. Maybe space travel is as impossible just not as obvious?

That's the thing : maybe there are laws that will forever forbid us to travel through space, but if there are, we don't know them - and there are no indication that they exist.
Let's be optimistic :)

Well, duh...

[QuietLagoon]

Forget Space Travel, It's Just a Dream ... at least with current technologies

.
Isn't that what dreams are about? Inventing new technologies to do in the future what is not possible now?

Re:Space Travel is a silly idea

[Runaway1956]

I can't argue with you, wjousts, because you are right. But, I'm more concerned with that huge rock that the scientists haven't discovered yet, which is on a collision course with the earth. That sucker is HUGE - nearly the same size as the rock they say caused the moon.

Life on earth will probably survive that impact, but I don't think it will be "life as we know it".

Re:Space Travel is a silly idea

[Xacid]

Asteroid mining?

Actually it's physics and BIOLOGY

[wisebabo]

The quick answer (which I'm sure many posters have already said) is don't involve chemistry; use nuclear engines, or ion engines or solar sails or magnetic balloons. There is a lot more energy (million fold) in nuclear bonds that you can get from fission reactors or by using the fusion furnace at the center of our solar system.

That said, I haven't really heard of good answers to long time LIVING (not just survival) outside of the earth's magnetic field/shield and without one-gee acceleration keeping our bodies reasonably fit. Want to COLONIZE Mars and not just go there for a flags and footprints mission? Well we have no idea if the 1/3 G gravity will keep the astronaut's bones from becoming brittle. Who knows if women can give birth to healthy infants in such an environment or even if we can grow crops there! (I really thought they shouldn't have cancelled the centrifuge that was to be a part of the ISS. Hopefully, if the Falcon 9 works out, it'll be cheap enough to add it later).

I'm actually a little more optimistic about the long term ability of humanity to spread throughout the cosmos. In just a few decades, hopefully we'll know enough about our biology to really tinker with it. Getting rid of susceptibility to low gravity is a given of course but how about a little radiation hardening? (Some organisms can tolerate millions of times as much radiation as we can). Perhaps later we could learn to deal with decompression sicknesses (like marine mammals) so spacesuit design could become a lot simpler. Maybe we could learn the tricks of hibernation from bears and squirrels so long space flights wouldn't consume so many resources (and be so boring!).

We might end up not quite the same as homo sapiens. Call it man plus. (For INTERSTELLAR travel, we'll need some pretty spectacular physics or some pretty radical reengineering of ourselves. How 'bout brains in boxes? Or better yet, just software running on commodity hardware?).

But it might take awhile.

Re:Actually it's physics and BIOLOGY

[maxume]

Marine mammals avoid decompression problems by not breathing underwater (for divers, the problems come from needing to inflate their lungs under high ambient pressures; dolphins and whales inflate their lungs at 1 atmosphere of pressure).

Re:Actually it's physics and BIOLOGY

[sznupi]

Biology is something we can check reasonably well, reasonably soon. Yes, too bad the centrifuge module for ISS was shelved... but OTOH there seems to be some newfound rush towards the Moon - I wish one of the landers would include, say, a small colony of laboratory mice, with monitoring equipment. Or maybe even return capsule, to return them after few generations (too bad cats would be too big... but imagine... [dramatic music]space cats!!![/dramatic music])

Also you have some dated info, we know very well that crops can grow in low gravity... heck, some Soviet experiments suggest that even ~month long day&night cycle on the Moon wouldn't be too much of an issue. Also, we already perform deep hibernation of humans (very conveniently for space travel: in miniaturized state), and on a mass scale - at least few dozen thousands living humans are past the procedure, IIRC.

And generally - "fast" means of space travel would barely make any kind of difference vs. "slow" ones (such as asteroid and comet hopping - around a trillion comets just in our cloud... and eventually, after a few thousand years, some groups would hitch a ride with a cloud of passing star); both offer very rapid colonization of the galaxy, in geological timescale.

Re:Actually it's physics and BIOLOGY

[ElectricTurtle]

While gravity differences can be mitigated a little by clothing designed to exert pressure on the wearers (designs already exist), even without guided and deliberate genetic engineering life on Mars would be so significantly different even in an artificially controlled habitat that the colonists there would probably start to develop into a new human species in a several generations. Between the differences in gravity, radiation, atmosphere, etc. etc. even with terraforming the most likely occurrence is that permanent human settlers would meet the terraforming process somewhere in the middle. (Environmental pressures have done as much on earth, not creating separate species, but if you compare the average traits of Eskimos vs. Maasai, there's a reason why Eskimos tend to be short and fat and Maasai tall and thin (among many traits)... the environment has selected for those so that Eskimos' body shape keeps more heat and Maasai's allows them to stay cooler.)

Farming however is irrelevant and in a few centuries will be looked upon as quaint. Hydroponics is far more efficient in both space required and resources consumed/produced. Farming is just so cheap and the infrastructure for it is already in place that it will be a while before the population pressures finally force society to build hydroponic production facilities on a large scale.

Re:Actually it's physics and BIOLOGY

[Nadaka]

Gravity isn't a problem if you can construct infrastructure in place before the astronauts arrive. And like you said, we don't know if mildly low gravity causes similar issues to zero gravity. If it does you can mount a portion of your colony on a train running over an inclined circular track or on a pivoting boom arm, and you can amplify the felt force of gravity.

Re:Actually it's physics and BIOLOGY

[Tom]

If it does you can mount a portion of your colony on a train running over an inclined circular track or on a pivoting boom arm, and you can amplify the felt force of gravity.

Which requires quite a bit of energy to run, not to mention other problems.

If low gravity turns out to be a major problem, and it very likely will, space stations (which can spin easily) might be our best option until genetic engineering has advanced sufficiently.

Nobody said such space stations can't be stationary over a planet, with space elevators doing the lifting, so our first Mars colony could actually be a space station in orbit, with mostly automated factories etc. on the surface to produce whatever the station needs. Which solves the problem with stations that it is horribly expensive and complex to make one really self-sufficient. Splitting the colony into a surface and an orbit part solves most of the problems of either approach.

Re:Actually it's physics and BIOLOGY

[Nadaka]

The energy cost of orbiting and de-orbiting personnel are so horrific, even with a "space elevator" that the cost of running a train in a circular track so that colonists could spend a part of their day near 1g would be practically a rounding error.

Re:Actually it's physics and BIOLOGY

[brianerst]

Frederik Pohl beat you to the punch by about 35 years: Man Plus

Re:Actually it's physics and BIOLOGY

[vivian]

Actually there's a little more to it than that - lung expansion injuries are only one of the dangers divers face.
The real decompression problem is that nitrogen in the air is absorbed into body tissues at depth. If you absorb too much nitrogen it takes a long time to release it again without causing bubbles. Bubbles of nitrogen in your blood cause blockages and clots, which are not very nice.

Whales and dolphins are also absorbing nitrogen from tha air compressed in their lungs, (it's 1 atmosphere at the surace but gets compressed another atmosphere for every 10 meters deep they go) but usually adopt dive profiles that allow the absorbed nitrogen to escape safely without causing bubbles - deepest part of the dive first, then going up to shallower depths progressively.

Whales however can get bent - http://news.sciencemag.org/sciencenow/2007/12/14-02.html apparently, if they come up too fast after being scared by sonar.

Re:Actually it's physics and BIOLOGY

[Tom]

The energy cost of orbiting and de-orbiting personnel are so horrific,

As is flying out a space station, or a colony, or really anything, to Mars. We've just started thinking seriously about this problem. When the solution finally comes up, we'll probably all say "oh, it's so obvious!" - but until someone puts it into words, it's not.

Re:Actually it's physics and BIOLOGY

[Nadaka]

No. You are comparing apples and atom bombs.

You are talking about a more or less daily commute to and from orbit using propellant, or building a space elevator on mars and using that for a more or less daily commute. You are talking about magic.

No sane person is going to say we can fly a whole colony out to mars with anything less than an Orion type nuclear powered ship. What we can do, and do in the next few decades with current technology is create an automated seed factory capable of building a colony on mars without humans present from local materials. That is an exercise in engineering and politics (for the budget as it won't be cheap), not magic.

Re:Actually it's physics and BIOLOGY

[Tom]

You are talking about a more or less daily commute to and from orbit using propellant,

Where did you get the "daily" from? No, I'm more thinking about having largely automated mining facilities on the surface and the actual colony in orbit.

What we can do, and do in the next few decades with current technology is create an automated seed factory capable of building a colony on mars without humans present from local materials.

You missed the context. Sure we can build something there. The problem the OP posted about was whether or not the surface is even suitable for human colonists, even if they have a biodome. What about gravity?

Building a rocket is not very hard, you can do it in your backyard. Building one that reaches orbit is a larger problem in scale, but not complexity, a dedicated university team can probably do it. But lifting a human into orbit, that is where it gets tricky.
Same with the colony. Building something on Mars - I agree, not so tricky. We can do it today, theoretically. But building a colony of humans on Mars is a different beast, not just a larger beast.

Re:Actually it's physics and BIOLOGY

[Nadaka]

You would still have to lift material into orbit to supply an orbital colony. Even if you use material from asteroids, you still have to get it into a planetary orbit from its solar orbit. It makes ridiculously more sense in the long term to pt your colony where the resources and work are, and that is on the ground if you are colonizing mars.

I already addressed the gravity problem in my first post. A small reactor or moderately sized array of solar cells, could provide plenty of power to run a train in a circular track to amplify the felt gravity from the ~.3 to closer to 1 on the big IF that it is needed. 1/3 gravity is greatly different from microgravity, it is much much closer to normal. I would not bet that we would really need more gravity.

Re:Actually it's physics and BIOLOGY

[Tom]

You would still have to lift material into orbit to supply an orbital colony. Even if you use material from asteroids, you still have to get it into a planetary orbit from its solar orbit. It makes ridiculously more sense in the long term to pt your colony where the resources and work are, and that is on the ground if you are colonizing mars.

Sure it "makes sense". If you ignore that you're talking about human beings and what kind of environment they need.

I already addressed the gravity problem in my first post. A small reactor or moderately sized array of solar cells, could provide plenty of power to run a train in a circular track to amplify the felt gravity from the ~.3 to closer to 1 on the big IF that it is needed. 1/3 gravity is greatly different from microgravity, it is much much closer to normal. I would not bet that we would really need more gravity.

If you think you've addressed the problem, then you and I are talking about different sizes of colonies. How many people does yours have? A dozen or two? Yeah, you can fit the sleeping and living quarters for those on a train.

Now try a few thousand, or a few ten-thousand. An operation of this kind won't be profitable if you think small.

"Science of everything"? Don't make me laugh!

[ThunderBird89]

Despite calling itself a magazine on the "Science of everything", this Cosmos is pretty outdated. Last I remember, nobody bothered about chemical rockets for interplanetary or longer travel: they pack a lot of punch, but they're heavy and can't be used for continuous burns, just short corrections. For which they work fine.

Then there's the ion engine: low specific impulse, but can be used for long periods on end, perfect for shaving time off the free coast phase. Already operated on several spacecrafts.

Fusion rockets: medium specific impulse, though still nowhere near a hypergolic rocket, but still can be fired for months on end as long as you have fuel, and it also takes care of power generation. Requires a leap or two in LASER tech for ignition, otherwise possible (in 10-25 years, at most).

Project Orion: riding on the shockwaves of NUKES. Can you guess at the impulse? Also advances nuclear disarmament, but kinda risky (the astronauts ride in essentially a box over a dampened shield behind thousands of nukes. You really don't want one warhead to have a bad day...). Possible, requires international cooperation and massive balls of steel to try, so let's discount it for now.

Light sails and ion sails: low specific impulse, but carry no propellant, and can accelerate all the way to the edge of Sol, making for some significant velocity when it hits the heliopause. Technically possible with today's technology, but unneccesary.

So there, we could pretty much achieve sustainable interplanetary travel today if we put our mind to it. And if we really wanted it, we could have STL generation ships on the way in 50-100 years, at most.

Re:Space Travel is a silly idea

[Darth Snowshoe]

Christopher, why, oh why, do you want to sail west? Everybody knows, it's just water and more water. And then you fall off the edge of the world. What a waste! Look, can't you even read a map?

"at least with current technologies?"

[fishtorte]

Thank Eris for those last five words.

Troll!

[Jammer6502]

Please let us moderate the summaries. Bad summary of a bad article.

More plausable reason

[Anonymous Coward]

I think the real reason we won't be back in space is politics and lack of interest. Most people don't care, and there are more pressing needs here on earth. Now, there's always the possibility (and high probability) that the answers to many of our needs down here will come from technologies invented for or made possible by space travel, but most people don't care. They see only the immediate near-term, and can't see the big picture... Thusly, we will never really go back on any scale, and the science and research needed will never really be financed... at least not to any significant degree.

Re:You're forgetting about radiation

[dragonhunter21]

I might be missing something here, but wouldn't that be lethal? 1 Sv results in mild radiation poisoning, and 8 is death no matter what. You'd be sick in 4 hours and dead in 32.

Some Asimov reading required

[HECMAN]

The author of the article needs to read "Not final!" a short story by Isaac Asimov
    http://en.wikipedia.org/wiki/Not_Final

Re:Space Travel is a silly idea

[CRCulver]

It was understood in 1492 that the Earth is round. Please don't perpetuate the myth that people thought Columbus was going to fall off some edge of the world.

Haha... Not even to Mars?

[Jugalator]

The author makes it sounds like there's air resistance in space that makes it possible to go to the Moon but not to Mars... :p

"See, it's the air drag that makes the journey to Mars simply consume too much rocket fuel!"

Physics and chemistry can't "clash"...

[John Hasler]

...because chemistry is just applied physics.

Re:Space Travel is a silly idea

[camperdave]

People might find that idea uncomfortable now. Five billion years from now humanity's attitude might be a lot different.

Re:You're forgetting about radiation

[ThunderBird89]

With an elevator, you can slap on some more solid-state shielding without worrying about weight issues. Slap on enough to stop neutral particles, and deflect the rest by generating your own little magnetosphere. Problem solved (provided you have the power generation capacity to sustain the shield).

Whoever says "no" is always wrong

[tekrat]

I'd like to remind people that scientists as recently as the 1940's said that flight faster than the speed of sound was impossible. That flight beyond the atmosphere was impossible.

Before that, they said that flight was impossible, and anyone travelling faster than 35mph would kill the occupant.

Just ask any top-fuel dragster jockey about what's impossible. Engineers were swearing up and down that they had reached the limit of what internal combustion engines could do in the 60's, but the guys building the dragsters kept proving them wrong.

I'm sure as far back as cavemen, there was a 'scientist' that was positive that man-made fire was impossible.

The point is: Sooner or later, anyone that says that anything is impossible is proven wrong. Don't be a naysayer, be that someone that changes the world. Find the way to achieve the impossible.

Re:You're forgetting about radiation

[ElectricTurtle]

Your figures are wrong. If any of it were true no astronaut would live through a mission. Your own source even notes "Actual radiation dose measurements of Apollo crews measured by onboard dosimetry were, on average, 12 mSv." That's 0.12 Sv... relatively high vs. average everyday life but far from 'tens of Sv/hr' which would kill people.

Cosmos = science tabloid

[bradley13]

Reading Cosmos for science is like reading the National Enquirer for news. TFA presents a false dichotomy: it takes lots of energy to move stuff between space and the surface of the earth. Therefore space travel is impractical. Whats wrong with this?

• First, one you establish a real, mostly self-sufficient presence in space, there is no moving stuff back-and-forth to earth. Raw materials are abundant, and getting in and out of weaker gravity wells (like the moon) is no problem.
• Second, getting back into the earth's gravity well takes essentially no energy at all - only control.
• Lastly, who says that "chemistry" is the only energy source. Nuclear power offers immensely higher energy densities. Like nuclear power for electricity, nuclear propulsion may well be safer than the chemical alternatives.

Space travel takes a huge initial investment to establish a real infrastructure, including mining and manufacturing. After that, it's all gravy.

New Technology

[Rhawk187]

Yes, lots of things are possible with current levels of technology. That's why we invent new technology.

Impossible...

[Solensean]

Impossible is just a word people use to make themselves feel better when they quit.

Re:You're forgetting about radiation

[Anonymous Coward]

I think your dose rates are a bit high. Typical accumulated dose for a year on ISS is something like 10mGray (1 Rad(Si)). But get a bit farther out from Earth, and the dose does go up substantially.

A typical design spec for equipment heading off to Mars is 20kRad (Si), which is 30-50 time the "death in a few days" kind of dose (600 rem)

Re:Space Travel is a silly idea

[nbannerman]

I can only assume that your sense of humour also took a trip off the edge of the world...

Some of the tech needed for Mars is 19th century

[denzacar]

And not in a "build on the knowledge of past generations" kind of sense. Literally.

Also, compared to some other "adventures", the whole thing would be rather cheap. On budget too.

Re:You're forgetting about radiation

[ChrisMaple]

Your source is not impressive. They seem to think that radiation doesn't decrease as you get farther from the radiation generator.

VASIMR and space-based nuclear on the way

[estestvoispytatel]

Just a week ago I've seen the report on talks about cooperation between VASIMR's Ad Astra Rocket Company and some branch of Rosaviacosmos developing the Russian megawatt class space-based nuclear reactor. If they succeed, it will be your next level space drive.

just need a stargate addresses to dial

[Joe The Dragon]

just need a stargate addresses to dial

Re:just need a stargate addresses to dial

[Z00L00K]

Hand me a stargate and I'll dial.

I just need to get hold of Jack O'Neill first.

Re:just need a stargate addresses to dial

[SETIGuy]

That's also a great way to teraform Mars. Just hold the stargate open until the pressures equalize.

Re:just need a stargate addresses to dial

[Blackhalo]

That's also a great way to teraform Mars. Just hold the stargate open until the pressures equalize.

Might work better to dial Venus from Mars, for pressure equalization.

Re:just need a stargate addresses to dial

[SETIGuy]

I'll tell General O'Neil that you're volunteering to go to Venus to dial the Venus gate.

Re:Fuel

[TaoPhoenix]

I'm pretty sure "carry our own fuel" is fine - but you plan for fuel boosts along the way like a giant video game. It's all about staging. The docking tech is a little weird but it has to be "relatively easy" to make the docking interface. Then you launch up a bunch of fuel cargo ships and park them all in orbit. Once you think you have enough, you string them all out in a row at intervals. Then you just 1-UP your way to Mars.

Bonuses for multiplexing the types of energy - part solar, part stored fuel, debris gathering maybe for a ballast dump twice per route to save fuel on a course correction.

The bigger thing is we absolutely have to quit squabbling among ourselves and get a grip because it will take the resources of at least two nations to pull it off.

Wishful thinking doesn't guarantee results

[sznupi]

http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm

Ultimately, you can bet future won't be as imagined in works of popular fiction - because you must remember that's what scifi is. Grandiose, fabulous, "awesome" style of exploration depicted in those - that's catering to audiences which would be uncomfortable with anything too dissimilar from Earthy experiences; and coincidentally making the work of writers helluva easier. A sign of... limited imagination (how many people remember that we can already transport people while miniaturized and in deep hibernation? Heck, give me one medium launcher + additional few dozen million bucks, and I can transport at least a thousand living / viable humans to pretty much anywhere in our system), afraid to face what the wild realities of existing universe.

And ultimately, people will remain upset how space travel will most likely remain different from earthly experiences

BTW, how is that building of ships' hulls ignoring Archimedes' principle going along? It's over 2k years old, surely we should be able to ignore it by now, eh?

Re:Wishful thinking doesn't guarantee results

[RockClimbingFool]

BTW, how is that building of ships' hulls ignoring Archimedes' principle going along? It's over 2k years old, surely we should be able to ignore it by now, eh?

What about Hydrofoils?

Re:Wishful thinking doesn't guarantee results

[sznupi]

I still see Archimedean hulls over there :p (easy, in a place formerly behind the Iron Curtain - quite a bit of Meteor or Voskhod hydrofoils around)

I say it very precisely, "ships' hulls"/etc., for a reason :p But congrats, you're only the second, I believe, out of at least two dozen people replying to such posts [1] / how hardly anybody realizes the existence of hydrofoils is another example of ultimately limited (just liking to tell itself how "broad" it is) imagination (hydrofoils which don't change much of course, their properties resulting in limited use, and how their essence is quite "ancient" - dynamic suspension above the equilibrium by moving surfaces is how a lot of "biological" swimming happens. Also, we can probably agree that small bike-like hydrofoils without hulls, often muscle-powered, are a joke ;) )

1. Generally, posts dispelling tendencies to mix fiction and wishful thinking with reality, most often when... related to space activities, as above. This picture is useful too (airplanes from "our" times, no doubt influenced by rapid advances in marine tech 100+ years ago [2] - and we can even build them: take a Harrier, remove wings and canopy... doesn't make it a good idea), vs. "boring" reality (yes, typically this picture ;p It's not only a nice shot; also the most widely used passenger airliner, the airline (as far as my part of the woods goes), and one of few profitable ones)

2. One can wonder how strong was this effect in giving us the Shuttle - after all, scifi from 30s, 40s and 50s (times of rapid advances in airplane technology / I can see a pattern...) was full of "spaceplanes". Shuttle designers and decisionmakers grew up on those works of fiction before they gave us... an analogue of Catalina, at best (Spruce Goose, at worst); something which, again, looked very soothing to public already quite accustomed to airliners / Concorde. And which probably robbed as at least of a decade of progress; was obsolete (with automatic rendezvous & docking done in the 60s) before it seriously got onto drawing boards.

Build on Earth, get fuel for trip home from Mars

[denzacar]

http://en.wikipedia.org/wiki/Mars_Direct
http://en.wikipedia.org/wiki/Mars_for_Less

Or try this, if you are more partial to video.
And then... there's the colonization option.

Best part is, no unobtainium needed. Everything is based on current, tried technologies already in use.

Physics

[mangu]

We have known since the 1930s that the energy bounding atoms together is nothing compared to the energy bounding the atom nucleus together. In the 1940s we started learning how to use that energy.

We have been stalling ever since. It's like we stopped developing automobiles because some people became afraid of them.

Re:Physics

[Shark]

It's like we stopped developing automobiles because some people became afraid of them.

I'm pretty sure, we're getting there already too.

Re:Physics

[grumling]

Not really. It just appears that way because we're seeing it in real time. Witness the particle physics research going on at CERN, Fermilab and other places around the world.

I'm sure James Watt's engine was the only design that was built for quite a few years too. Maybe not 60 years, but remember that particle physics isn't a backyard project.

Re:Physics

[mangu]

I'm sure James Watt's engine was the only design that was built for quite a few years too

Actually, the Watt engine was a third generation engine.

The first commercial steam engines were built by Thomas Savery. The second generation were Newcomen engines. James Watt invented the separate condenser, which allowed a more economic operation than Newcomen engines.

Watt then went on to invent further improvements, in the double action and rotative beam engines. Until them, steam engines were limited to back and forth motion, adequate for pumping water from mines, which was their first application, but in industry one usually needs rotating motions.

Re:Physics

[Rei]

Even chemical fuels have hardly evolved as far as is physically possible. Metastable compounds offer a whole new class of propellants with performance as much as an order of magnitude greater than current propellants. Cryogenic solid and hybrid rockets have hardly even been studied yet (you can even use solid oxidizers). Etc. And then there's the whole other class of improvements: spacecraft mass. Anyone here want to argue that materials have advanced as far as they're ever going to? Anyone?

Then, as you mentioned, nuclear energy is tremendous -- and need not be harnessed directly (you don't have to have a radioactive plume shooting out the back). There's also external energy delivery mechanisms, so your craft need not carry its energy onboard. And there are even some more radical concepts that I know some people who are working on. I can't discuss all of them, as not all of them have been published about yet, but I'll point out one that has: digital quantum batteries. This involves storing energy in arrays of nanocapacitors, whose small size enables quantum effects to require huge voltages for dielectric breakdown. When you take quantum effects into account for energy storage, the theoretical upper bounds on your energy density are similar to that of nuclear reactions (although the specific case I mentioned has tensile strength limits which are much lower -- but this does not apply to all systems).

And finally, the whole premise of the article is totally wrong. The article acts as though energy costs are the primary -- or even a major -- cost of launching rockets. They're not. If you can make a rocket where your propellant cost is a significant fraction of your launch costs, you're doing something *right*. Rocket costs are overwhelmingly parts and labor. Anyone want to make an argument that parts and labor costs on a complex system can never be reduced? Anyone?

Pretty much everything they wrote is wrong. For example, concerning the difficulty of mining water, etc off-world:

Davies' hope is that the colonisers might be able to survive indefinitely by mining oxygen, water, hydrogen and other resources at the destination. While possible in principle, this would be very difficult in practice because of the low grade of the resources.

*What*? We can't mine ice because it's "low grade"? What on Earth is he talking about? Many bodies in our solar system are covered in, or at least have regions of, nearly pure ice. Mars deposits 100% pure frost on surfaces near its poles. The frost will get contaminated by dust, of course, but it's freaking dust. If you can't filter dust out of water, something is wrong with you. "Other resources"? Like what, iron? Lunar regolith is 1-2% pure iron. Not iron oxide -- *metallic*. As in, "attract it with a magnet and then melt it". Iron miners on Earth would kill to be able to get iron that easily. Low grade resources my arse. The problem with off-planet mining is the cost and difficulty of engineering and transporting light-weight, highly autonomous mining/processing equipment and providing them with their needed consumables and maintenance. It has nothing to do with the quality of the resources.

Who decided to give this person a platform?

Re:Physics

[LifesABeach]

People use to say the same about breaking the Sound Barrier, space travel apparently has the same arguments that air travel use to have; I'm not surprised.

Re:Physics

[Wyatt Earp]

No, the sound barrier was a perceived issue, aircraft with propellers couldn't break the sound barrier because of drag, shock waves and turbulence no matter how much horse power you put behind the prop.

All of these effects, although unrelated in most ways, led to the concept of a "barrier" that makes it difficult for an aircraft to break the speed of sound.

Bullets and other man made objects could become supersonic so engineers knew it could be done somehow.

The rocket plane and latter, the jet plane made it possible.

Theres no similar observation about space travel, we aren't scratching our heads about our inability to do it with men while inanimate objects defy the rules.

Re:Physics

[fractalspace]

digital quantum batteries. This involves storing energy in arrays of nanocapacitors, whose small size enables quantum effects to require huge voltages for dielectric breakdown.

These batteries deliver 1.5, 3, 5, 6, 12,48, 110 and 220V. All at the same time.

Re:Physics

[mcmonkey]

Theres no similar observation about space travel, we aren't scratching our heads about our inability to do it with men while inanimate objects defy the rules.

Did you read what you wrote? There is exactly a similar observation about space travel. We have sent inanimate objects to other planets and even outside of the solar system. (Outer limits? Not sure where the solar system ends.)

This is precisely a case of trying to do with people what we've done with inanimate objects.

Three issues I have with the article 1) why plan a round trip? I skimmed the article, and it addresses the issue of launching enough stuff to keep folks alive there and back. Forget that, what about the time?

It's going to take so long to get anywhere, it'll be time to turn around and come home as soon as you arrive. Make it a one way mission.

2) As for the amount of stuff to support the mission, yes it's too expensive to launch all the needed supplies from Earth. So don't do it. Let's assume any interplanetary mission will have to pick up supplies on the way. So we have to have a target with water, for example, or plan to harvest a comet on the way. But none of that means it can't be done.

3) So it doesn't work with current technology. Technology changes. Yes, rocket technology does not have the growth of Moore's Law or the amount of pr0n on the internet. So what?

The limit on the amount of stuff we can launch from the surface of Earth is one small aspect of the problem, and one we can work around.

Re:Physics

[Wyatt Earp]

No, its not the exact observation about space travel.

"People use to say the same about breaking the Sound Barrier, space travel apparently has the same arguments that air travel use to have; I'm not surprised."

They are completely different because the Sound Barrier was a perception without any hard reason why it couldn't be done. We had things breaking the sound barrier thousands or millions of times a day, we just couldn't get one thing past it, propeller driven aircraft.

The article, and people here, are talking about how there are actual physical barriers to manned space flight in the Solar System, radiation, chemical, energy and mass barriers to it.

You want to make it a one way mission to say Mars? You realize that with current and near term technology, anyone on a one way trip to Mars is going to just die there.

I can't foresee spending hundreds of billions of dollars for a suicide.

Re:Physics

[Mogusha]

I find it interesting that it sounds like they're only talking about rocket thrusters that use some kind of chemical propellant. There are many types of thrusters that can get fuel from external sources. https://secure.wikimedia.org/wikipedia/en/wiki/Ion_thruster https://secure.wikimedia.org/wikipedia/en/wiki/Solar_sail This means we don't have to bring as much fuel. Or can generate more thrust than simple chemical reactions alone. https://secure.wikimedia.org/wikipedia/en/wiki/Project_Orion_(nuclear_propulsion) As some examples. Although, it would seem that the decrease in impulse of the renewable fuel sources would probably mean a longer journey than with chemical propellants. Which would mean more food weight. Which would only increase the problems they have with vitamine deterioration in the food they have on board. Vitamine C deteriorates fairly fast... maybe they should just bring a bunch of cats to eat, they generate their own.

Re:Physics

[Antisyzygy]

This guy Alan Finkel is a self described "Neuroscientist and Entrepreneur". What concerns me is the latter. Generally, people that describe themselves as that have large egos and little to back it up with other than they got lucky with an idea and made some decent money. Since this guy's only other real credential is being a neuroscientist, I doubt he understands the finer details of space travel.

Re:Physics

[Grishnakh]

Then, as you mentioned, nuclear energy is tremendous -- and need not be harnessed directly (you don't have to have a radioactive plume shooting out the back).

Who cares if there's a radioactive plume shooting out the back? Obviously, you wouldn't want to use such a rocket for launches from Earth's surface, used within our atmosphere, but for a ship assembled in orbit to be launched to other planets, why not? This is definitely a case where anti-nuclear hysteria is holding us back.

The article acts as though energy costs are the primary -- or even a major -- cost of launching rockets. They're not. If you can make a rocket where your propellant cost is a significant fraction of your launch costs, you're doing something *right*. Rocket costs are overwhelmingly parts and labor.

I'm not sure, but I thought the problem here was in getting humans to other planets and back, with a short travel time. My understanding is that this requires enormous quantities of energy. Yes, we've launched automated probes to other planets with very little energy, but that's because they take routes which require very little energy (taking advantage of the relative positions of the planets and their gravitational fields), but the trade-off is that the travel time is ridiculously long: months or even years just to get to Mars or Mercury. Look how long it took to get MESSENGER into its final orbit around Mercury. People don't want to wait that long inside a ship, and also they need lots of supplies so a longer journey means more supplies needed, so for human travel, we need much more powerful rockets so we can brute-force our way around the Solar System.

But again, the answer is quite simple: stop messing around with chemistry, and use nuclear rockets. As long as we refuse to further develop nuclear power, we're always going to be held back and never be able to advance very much.

Re:Physics

[Skywolfblue]

The article, and people here, are talking about how there are actual physical barriers to manned space flight in the Solar System, radiation, chemical, energy and mass barriers to it.

They're not inviolate barriers (like the speed of light). Build a big enough ship with a ton of water to shield the crew and a truly astonishing amount of chemical propellent (or a plasma/nuke drive) and all the problems go away. It's just economically, sensibly and manufacturingwise unfeasible.

Re:Physics

[Rei]

Just because you don't follow materials technology doesn't mean it hasn't advanced.

Just look at the backpacking gear market. When I was growing up, the lightest waterproof fabrics you could get that wouldn't fall apart in an instant was polyurethane, several ounces per square meter. For years now, the best has been silnylon, at just over 1 ounce per square meter. Now it's stuff like cuben, at about a third of an ounce per square meter. That's an order of magnitude improvement since I grew up. You see that in every type of backpacking material. When I was growing up, GoreTex was the new thing. Wow, a plastic that will (mostly) keep water out and let your skin breathe (a little)! It's laughable compared to modern fabrics like Epic. And abrasion resistant-fabrics, and high tensile strength per unit mass cords, and on and on... materials tech just keeps taking off. Carbon Fiber wasn't invented until the 1960s. The first carbon fibers were only 55% carbon and rather weak. By the late 1970s, they were up to 85%. NASA largely pioneered the development of RCC (Reinforced Carbon-Carbon) during the Shuttle Program, eventually leading to commercial applications like brake disks. But RCC itself is already being replaced by C/SIC. And the thing is, we've barely even started to take advantage of the amazing material properties that nanoscale assembly can provide.

And what on Earth does Mars's lack of a magnetosphere have to do with anything?

Re:Physics

[Rei]

It doesn't matter whether you use a low-energy launch trajectory or a high energy; the cost isn't the energy. It's the spacecraft designed to harness said energy. If you want a higher energy trajectory, you not only need more propellant, but a more expensive rocket; it doesn't change the equation. The propellant is still only in the low single digits as far as costs go. LOX, the most common oxidizer, is practically free compared to the cost of the rocket ;)

Re:Physics

[uninformedLuddite]

Quantum effects, dark matter, gravity waves they're all the same shit - YAWN

Re:You're forgetting about radiation

[clang_jangle]

Yes, the GPP's numbers are definitely off. We had astronauts spend four days each way on the moon missions, so it isn't quite as bad as that. I do recall reading though that a trip to the outer planets of our solar system with our current technology would leave the astronaut quite damaged by radiation. This is pretty old news, BTW, and TFS reads like some sci-fi fan just got his bubble popped after learning a few facts. Kinda cute, but on the front page of slashdot it just gives all the "/. == digg" complainers more ammunition. As if they needed it...

Re:You're forgetting about radiation

[pz]

I believe that 12 mSv is 0.012 Sv, not 0.12 Sv as stated.

Looks like a job for "stealthblimp!"

[erroneus]

Recently, there were a few postings mentioning the stealth blimp and I went to the linked page and found that according to the information there, blimps can go higher than traditional aircraft due to their method of lift. Question is, can it carry all that weight high enough for a lighter vehicle to thrust itself the rest of the way out of Earth's gravity? Theoretically, a device that is so far out should be able to be smaller and lighter while carrying a larger payload of supplies and life support gear.

Space elevators and all that are supposed to reduce the need for resources to escape the Earth's gravity. Stealth blimp oughta do it I think.

Re:Looks like a job for "stealthblimp!"

[John Hasler]

> ....the rest of the way out of Earth's gravity?

There's a fundamental misunderstanding here. Please review high school physics.

Re:worth and comfortable

[TaoPhoenix]

What if we split these two?

What if it's miserable as all get out - you start with an athlete and end up with a 40 year old nursing home resident - "It's just a man/woman". Before all the shocked people chime in, the value of a person is horribly flexible - it can take tons of work to train up someone, and then they can still get on the wrong side of luck.

But what if it's worth it?

Mars is possible

[scharkalvin]

It should be possible to get to Mars and back, however it won't be cheap. It would probably take the equivalent of as many Saturn V rockets as were ever launched to put enough material into Mars obit for ONE mission. This would include leaving in orbit the return rocket, and sending to the surface a return to obit craft (empty and landed by remote control or by computer). Then sending down the crew on a landing only craft and yet other landing craft with supplies. The crew wouldn't be able to take much back in samples, just dust perhaps. What would be sent back would be digitized data and photos.

Mars is the only planet in our solar system that we COULD visit. There are also the asteroids and here at least the gravity well is shallow enough that a return trip is on par with the visit to the moon. The author of the article is correct in the degree of difficulty of a Mars trip compared to going to the moon. I can't imagine it being worth while to send astronauts to explore Mars because we have done very well using robots. But impossible? No, just very expensive, risky, and not worth the price considering what other exploration could be done with the money.

Re:Mars is possible

[jandrese]

Ultimately, for the cost of sending one manned flight to Mars you can send a fleet of semi-autonomous robots that can do pretty much anything a human crew could do, but can stay there for months or years instead of days or weeks.

The reason we're not seriously considering sending people to Mars is not because there is a lack of "vision", it is because it just doesn't make sense.

Re:Mars is possible

[DrKnark]

It does not make sense if you only consider the short-term and disregard the resulting development of new tech. It is possible that the new tech and brainpower would make it worthwhile.

Re:Mars is possible

[jandrese]

That's true of the robotic space exploration program as well.

Re:Mars is possible

[FleaPlus]

It should be possible to get to Mars and back, however it won't be cheap. It would probably take the equivalent of as many Saturn V rockets as were ever launched to put enough material into Mars obit for ONE mission.

It turns out it's actually nowhere near that bad. If you look at the Mars DRA 3.0 architecture NASA released back in the 1990s, they could do a Mars mission using three launches of an 80mt vehicle:

http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/docs/MarsRef/addendum/A4.htm#A4.0

By comparison, the Saturn V was a 120mt vehicle. Just last week SpaceX announced that they're be building a 53mt vehicle which will be available for a price of $100M/launch. If the DRA 3.0 mission were repacked, it could potentially perform a Mars mission with ~5 Falcon Heavies, at a total launch cost of half a billion dollars. This is coincidentally much less than it costs to launch a Space Shuttle mission.

Re:Mars is possible

[DrKnark]

Of course. But it is not necessarily the case that the extra work to do manned flights is wasted. I'm not saying "we" (I'm not in the US) should rush off to do this, all I'm saying is that it is possible that the benefits could outweigh the costs. The benefits are of course at this point unclear, long-term benefits and cannot be quantified for many years if the project should be started.

Thank you!

[unassimilatible]

I'm a social science ("cough") major, and even I blanched at the mention of "rocket fuel" in the article. Nice assumption. I read about successful ion propulsion experiments years ago. Where have these guys been? I mean, it isn't rocket science, er...brain surgery.

Re:Thank you!

[ThunderBird89]

If I remember my "Ancient Astronautics History" properly, they were on the Deep Space probes, and one a probe that investigated the asteroid belt.

And just to illustrate the inanity of the article, the above came without looking anything up on the net (with the exception of the name of Project Orion, which almost became NERVA...), from the head of an international relations graduate.

Need a re-thinking of what a space ship is

[Pro923]

It needs to be broken down into parts... At some point we'll realize (or maybe not) that a vehicle that gets us from the ground to orbit is a completely different thing from a vehicle that gets us from one orbit to another. It's analogous to trying to use a boat to get from a point 100 miles inland on the US East Coast to a point 100 miles inland Europe. Sure, the boat is a good tool for most of the journey, but you need a different type of vehicle to traverse the 100 miles.

It is always impossible

[glatiak]

Let us not forget that in the 19th century there was some discussion about closing the Patent office because everything possible had already been invented. This is really nothing different. Later on there was powered flight, radio, computers, etc -- all quite impossible from the perspective of the mid-19th century. The part that I remember best about JFKs speach about going to the Moon was 'not because it is easy but because it is hard'. One might modestly suggest that it is only by trying to tackle the impossible problems that we learn anything. Setting the bar low and then not trying because, of course, it is impossible will always apeal to some people. Happily, the rest of us will leave them behind some day. But if we stop trying... then what they said will become true.

Re:It is always impossible

[Tanuki64]

Let us not forget that in the 19th century there was some discussion about closing the Patent office because everything possible had already been invented. This is really nothing different.

Yes, this is different. The more we know the smaller is the probability that we make grave misjudgements of what is possible and what not. And we know immensely more now than we did the 19th century.

Though it is not impossible that we are still missing some important laws of physics, which if we mastered them, would allow us easy space travel. But I would not bet my money on it.

Re:Forget it? I don't think so!

[DarkOx]

There are plenty of ideas out there that probably can work. Most of the technology exists, and just needs to be assembled into a single project. Its not even beyond the realm of economic possibility to implement some of these plans they question is why?

What is there on the moon or Mars to make it worth going there. Why should anyone want to live there? Don't say over population even if the population on earth continues to grow at the current rate somehow it will be along time before conditions here would be more cramped then they would be on space/moon/Mars base. Don't say resources its pretty evident that supporting one person on a space/moon/Mars base would take more resources from Earth that keeping that same person right here on Earth. The only reason to do it is for practice colonizing and for the investment required it probably makes more since to try and simulate things here on Terra.

There are for the most part know ways to build and power a multi-generational ship There is lots uninterrupted solar power and other radiation out there to scavenge for your day to day needs, and you could bring enough nuclear fuel from Earth to propel the craft. The trouble is where do want to go. Oh and your going to live the rest of your life in this box, you will never see the destination, nor will your children, their children, their children's children, and likely ten more generations after that. That is if you pick someplace nearby and NOTHING goes wrong. Who wants to take that risk and for what?

Re:We can get to Mars and baick.

[nusuth]

We have the technology. It is just impossible to send humans and their living quarters and their supplies and a research station and a return vehicle and return trip supplies on a SINGLE chemical rocket. Once you start using more than one chemical rocket for this list, even at just two, it becomes possible. (Unless you can do the smart thing and use a single nuclear rocket instead.) We already have demonstrated that we can resupply a spacecraft in orbit, do docking and assembly in orbit, do precision landings, survive long enough for the trip in space etc. The mission to Mars probably shall not use chemical rockets, but if we decide to use that technology, there are plenty of possibilities to make it happen. We can even colonize Mars with current *propulsion* technology (but new technologies are required for other aspects of colonization) : Aldrin Mars cyclers (basically Mir, ISS like stations in an interplanetary orbit) are sufficient for regular travels or resupply missions.

Re:You're forgetting about radiation

[fnj]

Yes, of course you're entirely correct; whole body exposure to 10 Sv is lethal. Your parent is way, way off.

From your parent's post's own link - "Actual radiation dose measurements of Apollo crews measured by onboard dosimetry were, on average, 12 mSv." That's for the entire two way flight, not per hour.

He may have been talking about the calculated dose of 6 Sv in space at Earth's distance from the Sun if a major solar particle event occurred. That's 6 Sv TO THE SKIN PER EVENT, not per hour, or 0.9 Sv to the bone marrow. Or intersecting the path of a coronal mass ejection or solar flare, you could take 10's of Sv if floating naked in space, but fractions of 1 Sv inside a spacecraft. Cosmic ray exposure could be between 0.3 to 1 Sv per YEAR. While all these considerations are very serious, they are far from the cataclysmic levels portrayed by the poster.

Re:You're forgetting about radiation

[filthpickle]

In case you haven't seen this.

xkcd radiation chart

New York Times had the same article in 1920

[Anonymous Coward]

http://astronauticsnow.com/history/goddard/index.html Old wine in new bottles. Will they never tire of this argument?

Learn how imagine... then learn how to add

[memyselfandeye]

This summary is such FUD, and the article is nearly so. The author is a Medical Doctor, and if Doctor's had their say humans would have never gone to low orbit in the first place! Physics tells us Moore's Law is not a Law, but rather an idiom that expresses human ingenuity in the field of electronics. Moore's Law does not say transistors can get indefinitely small, it says people can build cheaper and cheaper transistors on larger and larger circuits. I can double the payload capacity of LEO vehicles tomorrow. Give me a 747 at 40,000ft and a rocket, and I'll put up twice the cargo for half the cost of a conventional rocket launched from sea level. Physics says I can do that. I'm not sure what point the author is trying to make with Moore's law, but the comparison between human ingenuity in spaceflight and electronics, and the laws of nature, is mute. Just because it hasn't happened, doesn't mean it is impossible.

Mistaking a large Keynesian space program that explicitly prohibits large leaps in engineering is a common mistake people make when it comes to the impossibilities of space travel. The space station was built, in part, because NASA and Congress didn't know what to do with the large 'space truck.' What do you do when you've got giant reusable vehicles with a HUGE cargo hold? Apparently, you build a space station with it!

We have been living continuously in low orbit for decades without a single fatality. The only Americans who have ever died in space died coming and going, but once you’re up there it has been statistically much safer. One would think moving a group of humans 60-100M km over 9-15 months would be quite possible. We've been living in hostile environments here on Earth for almost a century now with submarines, where a person can't exactly go out for a walk 600ft under water. And in the last 40 years or so, the crews of big submarines have continuously lived underwater for months on end. We know how live in enclosed environments for long periods. If 200 men can go months on end without killing each other, I think a dozen over the hill astronauts might be able to do the same.

The hard part of going to Mars is leaving Earth and then landing safely, landing being the most difficult but NOT impossible feat. Physics tells us that all the elements needed to create breathable air, fuel, water and return fuel for indefinite exploration of Mars can be found on Mars. Physics tells us the power needed to make these compounds can be made on Mars as well. All with ‘current’ technology despite the "low grade" resources, as claimed by the author!

Physics tells us all the hazards of interplanetary travel can be reduced or mitigated. Physics tells us radiation can be reduced with shielding, as can micro meteorite impact dangers.

If you want to really learn what Physics says we Can and Can't do, I'd suggest checking out on of the all time greatest book on the subject, "Spacetime Physics" by Taylor and Wheeler from you public library.

You think that's science fiction? How about this. Physics tells us it's possible to put all the DNA of earth on a tiny little probe the size of a dime, complete with tiny robots, that can be quickly accelerated to large fractions of c and travel between stars in decades. These probes can smash into planets and build life for us. Why send our descendants in large cumbersome bodies when you can send the information needed to create them. The technology to do this doesn't exist yet, but we are developing it Now. And physics doesn't say anything here is impossible.

Re:You're forgetting about radiation

[fnj]

Did you even read the article you linked to? It doesn't say anything like what you claim. The steady state radiation dose in space is not 10's of Sv/h. The actual measured doses received by Apollo astronauts worked out to the microSv/h range.

Yes, solar events can be a very significant problem, but the picture you paint is fantastic in the literal sense of the word.

Re:We can get to Mars and baick.

[pecosdave]

What do you think of the idea of sending "progress" type payloads up? One or two in orbit, possibly ahead of the astronauts, one or two on a slow course they could catch up to, possibly even adding to the size of the vessel, and maybe even some already making a return trip before they leave they can catch on the way out? Sure the math to do the mid journey intercepts is difficult at best, but we've proven ourselves rather capable thus far. (launching on time on the other hand.....)

Re:worth and comfortable

[grumling]

Isn't that basically what we have now? With muscle atrophy on long duration flights astronauts usually can't stand in Earth's gravity for a few days, their hearts don't pump blood properly and their bones loose density. Yet we still have a long waiting list.

Re:Space Travel is a silly idea

[Kjella]

In a few billion years. Yeah I get it, you want to see it happen but if we take a thousand year hiatus and reboot our space exploration in the year 3000 that won't even amount to a rounding error. And we're still sending out probes, building bigger and better telescopes. We're just not sending fragile meatbags out there.

Re:You're forgetting about radiation

[splerdu]

It'd eventually become less lethal when/if we start spending more time in space (or near nuclear reactors) to evolve against the increased radiation. Cockroaches and insects are surprisingly hardy against radiation. And there are certain earthworms that evolved to become arsenic resistant.

It could be that our lack of exposure to radiation is what's preventing us from evolving biologically to become better-suited as a space-faring species.

bummer

[shadowrat]

The laws of physics and chemistry say i can't propel a car, a human payload, life support, and a snowboard from milwaukee to denver either. Somehow i manage to bypass them by stopping at a gas station.

Re:You're forgetting about radiation

[hedwards]

Astronauts rarely if ever go beyond the van Allen radiation belt, the only cases I can recall were when we sent astronauts to the moon. And those had to be pretty carefully timed due to the expected radiation exposure.

Re:We can get to Mars and baick.

[nusuth]

I guess that is possible but I don't see the point. What is the advantage of doing stuff en route to Mars rather than in Earth and Mars orbits?

We are still using 1960's technology for space

[brainzach]

This article is dead on. There hasn't been major progress in making rockets more efficient since the 1960's because the basics of chemistry and physics.

If we spend hundreds of billions of dollars, we might be able to send a select few men to Mars, but it would be like the lunar landings in the past. It will be a one time event then people will realize that it is a waste of money and resources to do it again.

The current technology won't work to make space travel apart of our daily lives. It won't support advances like suborbital commercial airplanes, space tourism, colonization, or mining the Moon and comets.

There has to be major advances in technology to make space travel that are order of magnitudes more efficient before any of these dreams becomes a reality. These technologies are mostly theoretical and probably won't be available during our lifetimes. Until then, we will just continue to spend billions to send a select few into space like we have been doing since the 60's.

Re:We are still using 1960's technology for space

[DerekLyons]

This article is dead on. There hasn't been major progress in making rockets more efficient since the 1960's because the basics of chemistry and physics.

If efficiency were the problem, that would be a concern.

Re:We are still using 1960's technology for space

[plopez]

We are using 60's technology since it has worked so far. Much like we continue to use 19th century automotive technology. Which, btw includes battery powered cars.

Re:We are still using 1960's technology for space

[grep_rocks]

You are right, the practical way is to use nuclear rockets, and physics says to put large payloads into space you need vast amounts of energy, this answer will not change and there are only so many ways to obtain the energy densities needed, furthermore it is unlikely people will discover cavorite or some other magic material to defy gravity or generate massive amounts of energy at the densities needed. In fact even if someone did discover such a thing it might be the worst thing ever to happen to life on earth. Take nuclear rockets, one example is the Orion nuclear rocket, which involved dropping nuclear or thermonuclear bombs out the back of a spacecraft to push a reaction plate (this was build-able using 60s technology and a pretty efficient design), I recall the rocket needed on the order of 200-500 bombs to get anywhere interesting in a reasonable amount of time - a good fraction of those bombs would have to be detonated in the earth's atmosphere, we get hysterical about one nuclear reactor having a partial melt down, how do you think people will feel with the _intentional_ detonation of 50 H-bombs in the atmosphere to launch one rocket? and who would want to put on one spaceship enough nuclear weapons to make that one spaceship a major world nuclear power? The power densities and energies needed for space travel are not compatible with a stable biosphere, unless you launch small light-weight robots into space which then go and build your interplanetary spaceships/weapons of mass destruction in space you are not going to see much human space travel.

Re:We are still using 1960's technology for space

[brainzach]

Battery power cars face the same problems that modern rockets do. The weight of the batteries makes it impractical to make a long distance electric car. When you add more batteries, it increases the weight of the car which makes it less efficient.

What made modern electric cars somewhat practical is chemistry that allowed batteries to have higher energy densities, which is new modern technology.

Unless they discover a new chemical reaction that is able to produce more energy per unit of mass, then there is not going to be significant advances in what conventional rockets can do. It is just simple physics.

Re:We are still using 1960's technology for space

[dcw3]

This article is dead on.

...arrival.

laws

[Tom]

Now consider the laws of chemistry. You canâ(TM)t change them by legislation.

I'm sure that doesn't stop our current-day politicians. These guys have been living in lala-land for a decade or more, sure they can.

Re:Space Travel is a silly idea

[Darth Snowshoe]

My drift here is that no one could very accurately predict the value that exploring ultimately would have, in Columbus' day, and I'm sure the same uncertainties are in effect today. This argument is much more thoroughly made in Zubrin's book, THE CASE FOR MARS, which I would encourage everyone to read. There are plenty of recent, surprising discoveries regarding Mars. There's also plenty yet to uncover there - firstly, "Hey, where is all this seasonal methane coming from, and where is it going to?"

Re:Space Travel is a silly idea

[Tom]

Because at some point the sun will turn into a red giant and swallow the earth whole.

Just as interstellar distances are unimaginable to most of us and our human-environment-size-and-time-scaled brains, so is time. We are about halfway through the lifetime of our sun, which means we still have a comfortable one to two billion years before any noticeable change.

We could wipe out all life - down to the bacteria and one-celled, I mean absolutely freaking everything - on the planet and there would be enough time for another sentient species to evolve. They'd have a lot less time, we don't. I really don't think we should worry now. Two billion years is plenty of time to come up with interstellar travel, even without trying.

We will be completely and irreversibility erased from the universe.

A lot of people find that thought rather uncomfortable.

If you worry about the sun going out, why not worry about whether or not K > 0? If there's going to be a "Big Crunch", then we'll be wiped out whether or not we go to the stars.

I honestly think there's something else to the whole space exploration meme. It is a symbol of freedom, because it is so huge that for alle we care it's unlimited in size and time. On a planet where we are just about to map the last few remaining white spots, that means a lot.

Re:Some of the tech needed for Mars is 19th centur

[radtea]

Also, compared to some other "adventures", [wikipedia.org] the whole thing would be rather cheap

The challenge for space travel is to get buy-in from the broader population, and to do that it has to have the same visceral, senseless emotional response that warfare has. War is mate competition carried out by other means, and as such engages our deepest emotional responses.

While exploration is daring and dangerous, the vast majority of people can't participate in it in an active way. We sent 12 people to the Moon, compared to hundreds of thousands rotated through Iraq.

So from my point of view the problem with exploring other worlds is that we aren't doing enough of it to engage a large enough segment of the population. If some country were to commit to militarizing the Moon, say, we'd see a vast increase in resources flung at space travel, and at this point I'm not sure that wouldn't be a bad thing. Even done by an organization as stupid and inefficient as any standing army, it would be cheaper and vastly less destructive than even a fairly tiny war.

Re:**CRACK*** *POP* *CRUNCH*

[Anonymous Coward]

Einstein didn't say that. That quote is from Edmund Burke's Preface to Brissot's Address

Re:We can get to Mars and baick.

[Plekto]

And this is why setting up operations eventually on the Moon is such a smart idea. We can waste less fuel getting into space(possibly even using some sort of Moon-based launching platform) and make it possible to use virtually off of the fuel for actually moving through space. Also, there are space and materials concerns that cease to be a real problem if you build on the Moon as you don't need to cram it all into a tiny space on a rocket. Even if you built something 6x the weight on the Moon as here on Earth, it would still take a fraction of the fuel to get into space as there's no atmosphere to deal with(among other advantages).

We can easily do this. We just need to get that Moon Base (tm) built first.

Re:Build on Earth, get fuel for trip home from Mar

[Guspaz]

Do we even need to do that? SpaceX and their competitors have (or promise to) significantly reduced the cost of getting payloads into orbit. If your goal is to use multiple heavy-lift launches to assemble the launch vehicle in orbit, why is that not doable today with a sufficiently large amount of money? I'm not saying it'd be cheap, but it's doable.

Part of the cost problem is that it currently costs NASA roughly 12x more than it costs SpaceX to get payload into LEO (based on $450 million per shuttle launch). It's hard to do such a mission affordably when your costs are so obscenely high.

Space habits are still very interesting...

[Paul Fernhout]

An I wrote about on Slashdot was it approaching a decade ago?
    "Both CATS and DOGS are needed... (Score:2)"
    http://slashdot.org/comments.pl?cid=5821178&sid=62113

See also, from J.D. Bernal in the 1920s(!):
    http://www.cscs.umich.edu/~crshalizi/Bernal/world/
"Imagine a spherical shell ten miles or so in diameter, made of the lightest materials and mostly hollow; for this purpose the new molecular materials would be admirably suited. Owing to the absence of gravitation its construction would not be an engineering feat of any magnitude. The source of the material out of which this would be made would only be in small part drawn from the earth; for the great bulk of the structure would be made out of the substance of one or more smaller asteroids, rings of Saturn or other planetary detritus. The initial stages of construction are the most difficult to imagine. They will probably consist of attaching an asteroid of some hundred years or so diameter to a space vessel, hollowing it out and using the removed material to build the first protective shell. Afterwards the shell could be re-worked, bit by bit, using elaborated and more suitable substances and at the same time increasing its size by diminishing its thickness. The globe would fulfil all the functions by which our earth manages to support life. In default of a gravitational field it has, perforce, to keep its atmosphere and the greater portion of its life inside; but as all its nourishment comes in the form of energy through its outer surface it would be forced to resemble on the whole an enormously complicated single-celled plant."

We can do this, and we can support quadrillions of people (and other beings) living in the solar system in space habitats. The only question is if we want to.

So, while there may be limits to growth, we are nowhere near them when considering the solar system.

That article is just ignorant in part because it ignores things like laser launched craft or possibly the new cold fusion ideas (by Rossi, if they work out):
    http://pesn.com/2011/04/07/9501805_Rossi_Cold_Fusion_Validated_by_Swedish_Skeptics_Society/

Also, it says resources are not concentrated, but that is what energy and robots are for.

So, it is a pretty ignorant and defeatist article.

A better thing:
    http://www.islandone.org/MMSG/aasm/

My hopes:
    http://www.kurtz-fernhout.com/oscomak/
   

Re:Space habits are still very interesting...

[plopez]

"Imagine a spherical shell ten miles or so in diameter, made of the lightest materials and mostly hollow; for this purpose the new molecular materials would be admirably suited. Owing to the absence of gravitation its construction would not be an engineering feat of any magnitude."

Except for getting the materials and construction equipment "on site". I assume it would have to come from a planet, or by corraling asteroids. There's no free lunch.

Re:You're forgetting about radiation

[Plekto]

This is yet another reason why we need to perfect some sort of suspended animation technology first. If the crew member is in a self-contained and largely radiation-proof tank/capsule/etc for the times where they are not in orbit around some planet, then radiation isn't really a major concern. This can be mitigated, though, by building heavier shielding, though. But this means we'd have to assemble the ship in orbit or on the Moon. Adding ten tons of lead plating to your ship's hull isn't quite feasible if you do it on the ground ;)

3 ways to break the barrier.

[Anonymous Coward]

3 ways to break the barrier.

1- Space industrialization through telepresence (on Moon and/or Near Earth Objects, where real time telepresence is possible)
Spaceships on space could be extremelly efficient. The most cost is break the Earth's gravity barrier.
2- Space elevator.
An elevator don't have the losses of a rocket, so you break the barrier on other way.
3- Aneutronic fusion power scaled down.
Altought the most difficult in technology, the incredible energy density of fusion if possible on a spaceship scale, and the absence of radiation of aneutronic fusion would allow incredible spaceships capable of Single Stage to Orbit very similar to todays airplanes.

Re:3 ways to break the barrier.

[JSBiff]

I would point out that leaving earth's gravity well, while a significant source of required energy, is not the only one. To reach Mars in a reasonable time frame (say approx. 180 days; that is, 6 months), you need to accellerate the mass of the entire vessel and contents up to a fairly high speed (I don't know enough about orbital mechanics and calculating trajectories and things to figure out the path, or the speed, but I'm pretty sure it's a pretty high speed).

Even with no gravity, accelerating a mass to a high speed takes a lot of energy. The classical physics equation would be E_k (kinetic energy) = 1/2mv^2. I don't think the speeds are high enough to need to bother with the more complicated relativity equations?

Then, you need to expend nearly the same amount of energy as you near mars to match velocity/orbits with mars so you don't enter it's atmosphere and gravity well going too fast.

So, a space elevator only partially reduces the energy requirements. Space elevator would be much more useful for things like putting new satellites in orbit. And dropping rocks on your enemies *grin*.

Re:3 ways to break the barrier.

[JSBiff]

Using a chemical launch rocket to get into outer earth orbit will likely always remain more practical than a space elevator. Like you say, from their you can use other means.

Would ion drives be unsafe for terrestrial launch, so that you have to get into orbit before you can fire them up? I've wondered about that - I suppose that a high energy Ion stream would probably be a pretty hazardous thing to organic life - it would basically be ionizing radiation, right?

Means other than chemical...

[Zelig]

The author of the original article is presumedly no dummy, and I agree with his analysis as far as it goes. But he makes no attempt to discuss travel powered by something other than chemical rockets you bring along.

VASIMIR is one alternative, which will indeed gain efficiencies from Moore's law (extremely rapid adjustments to optmiize magnetic field?).

The juice to run that can come from nukes or solar...

Chemical fuels are a barrier to chemical propulsion, that's all.

Re:You're forgetting about radiation

[Thiez]

Seriously? Let's expose thousands of humans to radiation for several (hundreds, or more likely thousands) generations. Sure, most of them will die horribly of cancer, but perhaps they'll evolve radiation resistance. Those pesky ethics are holding us back!

You sir are a horrible person.

Re:You're forgetting about radiation

[danlip]

Insects are more resistant to radiation because they have simple bodies, short life cycles, and huge numbers of offspring. We're not likely to ever evolve radiation resistance. Or superpowers, unfortunately.

Re:Forget it? I don't think so!

[oodaloop]

Yeah. And someone once proved communication with Mars was impossible, since it would require a flag so huge it would be impossible to wave.

Humans to Mars? Probably never.

[rclandrum]

It's not the radiation or the length of time or the fuel that will keep humans from going to Mars - it's the lack of will and funding, combined with the advance of robotics. Has anyone seen the "artists conception" video of the upcoming Mars Science Laboratory that they will be landing on Mars in 2012? As I watched that thing, my jaw dropped lower and lower - if we actually manage to pull this robotic mission off, I'm convinced that we will never personally go there unless someone whips up a magic transporter. Figure it out - one one hand we can send robots to Mars on the (relative) cheap that let us explore, test, examine, and travel to just about anywhere we want to go, and we can keep sending more and more sophisticated bots. Balance the bot strategy with the incredible expense, human suffering, risk, and probability of actually learning anything new of going there personally. On balance, it just ain't worth it. If we can actually build automated spacecraft and rovers that can do what is pictured in that video, then game over. Bots are the way to go. I used to be a strong "send humans to Mars" proponent, but after watching that vid, I humbly admit that our real strength lies in our proven ability to design semi-autonomous spacecraft and incredibly productive bots, and that's the best way to leverage our money. Google for "Mars Science Laboratory Mission Animation".

Re:Fuel

[Arlet]

Seems very complicated. First of all, these fuel depots will be in different orbits, going at different speeds, and your main craft zips by at yet another speed. How are you going to align everything, and what happens if you miss the launch window ?

Carrying your own fuel seems much simpler.

A Song for the Dream

[rssrss]

"Well I dreamed I saw the silver
space ships flying
In the yellow haze of the sun
There were children crying
and colors flying
All around the chosen ones
All in a dream, all in a dream
The loading had begun
All in a dream, all in a dream
The loading had begun
They were flying Mother Nature's
silver seed to a new home in the sun"

"After the Gold Rush" by Neil Young

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Practicality & safety

[captainpanic]

So far, people thought it dangerous enough to sit on top of a conventional bomb which undergoes a controlled reaction.

But indeed, maybe in the future we can find people who wish to strap themselves onto a nuclear bomb which undergoes a controlled nuclear reaction. Why not? :-)

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Re:You're forgetting about radiation

[dryeo]

Gemini XI used the Agena to boost to 739 miles. Not sure how that relates to the van Allen belt.

Build the Hotel before you send the guests.

[MarkvW]

We need to focus on developing an energy source that powers self-replicating robots that are capable of building more self-replicating robots, more energy sources, and (especially) the facilities necessary to sustain human life. This is an amazing challenge.

We should build the hotel on the other planet before we send the guests.

Light sails...

[rgbatduke]

The article is IMO incorrect because it concentrates only on chemical reaction motors. There, of course, their answer is correct. But that isn't the only way to move around in the solar system. One question I ask my intro physics students is to contemplate the light sail as a means of propulsion. To do this, one simply works out the balance between solar gravity and radiation pressure to determine how thin a sail has to be in order to directly support its own weight (and the answer, of course, is "very, very thin":-).

However, this isn't the end of the problem. I then ask them how much force is required to remain in orbit. The answer (neglecting the tiny amount of atmospheric drag in near earth orbits and e.g. tides) is "none" -- orbit is free fall where the centripetal force required to bend the trajectory into a circle is provided by gravity. A feasible light sail can be built that can exert enough force via reflected sunlight to provide an acceleration of (say) a millimeter per second squared for it and its payload in a scalable way, or even more (with sub-micron sail designs). Not much, but given 86400 seconds per day, that is as much as 86 m/sec (or nearly 200 mph) delta-vee per day, for free, every day. One can add a kilometer per second every two weeks, and that's enough to reach anywhere in the solar system in time, especially if you amplify it with a gravitational slingshot off of (say) the moon.

Sure, it would take too long to move humans around, but that isn't the challenge -- we can move humans around now at large but not impossibly large expense, at least as far as Mars or Jupiter or Venus, even using chemical rockets although there are probably better solutions than chemistry in the long run. The only really hard part is getting things into low Earth orbit -- once there you are "halfway to anywhere" as Heinlein liked to put it (virial theorem) and light sails mean getting the rest of the way is scalably/reusably "free" if you don't care about taking order of years to get there. Light sails would let us move everything that isn't a human to e.g. the Moon or Mars to set up a more or less permanent base and maintain a long-term line of supply. Who cares if your food and water take years to get there, as long as they get there cheaply enough?

A second thing that would change the economics (aside from either new physics or radically new ideas, e.g. a fusion-driven relativistic ion drive that again uses free or abundant energy to eke the maximum possible reaction thrust out of reaction mass by accelerating it to close to c where it has a lot of momentum per particle) would be to build light-sail driven robots to mine the asteroid belt for raw materials so that we wouldn't have to lift e.g. steel, nickel, and possibly even water up to Earth orbit. Those robots could equally well deliver mass back to Earth at e.g. the Earth-Moon Lagrange points and allow extended permanent habitats to be constructed there that are a light sail away from anywhere.

The only thing preventing us from settling the solar system is time and the will to do it -- we could do it now for a tiny fraction of what our military forces cost us every year. Sure, it would be good to find solutions to the time problem -- it's easy and cheap if we don't mind transit times of decades, so perhaps working on various forms of suspended animation would permit humans to take the light sail route as well as their food, clothing, water, air, and construction materials. A Lagrange point colony with a decades-long, robot-filled pipeline of raw materials could create a steady flow of humans moving out to permanent colonies throughout the solar system on a timescale of centuries.

Or, as some clever human posted yesterday, perhaps a flying saucer really did crash at Roswell. If so, then interstellar travel is indeed feasible somehow, which means that there is likely a solution waiting in new physics. If the federal government would just 'fess up

Re:You're forgetting about radiation

[dragonhunter21]

If the crew member is in a self-contained and largely radiation-proof tank/capsule/etc for the times where they are not in orbit around some planet, then radiation isn't really a major concern.

They have those now, actually. We call them spaceships.

Besides, I don't see how suspended animation technology would mitigate radiation exposure. The DNA damage would still occur. if anything it might be worse- the body doesn't have much chance to repair the damage if you're in hypersleep, so when you wake up all the damage catches up to you at once.

Re:We can get to Mars and baick.

[Vectormatic]

slow courses and catching up dont really work, if you catch up to your supply ship at 1000 km/h, that means that to dock peacefully, either you need to slow down a lot, of the other craft needs to speed up a lot. I also suspect continously differing transit trajectories between earth/mars would screw it up big time.

The obvious trick would be to just stage the supplies in mars orbit

Re:We can get to Mars and baick.

[h4rr4r]

No. Check out DeltaV for earth and moon. Even worse remember that everything will have to go from earth to moon, then out. Your plan actually makes it more expensive. It would be cheaper to just launch from the earth to target. Unless you think that all the stuff you want to take to space is already sitting on the moon waiting.

Forget the gravity

[vampirbg]

There is one fundamentally wrong presumption here, and it's the notion that the craft would be sent from Earth. If you could build an orbital station and devise a way to get resources to it then you could assemble and produce spaceships without worrying about gravity, size, aerodynamics etc. Since there is no friction in space once you reach the desired velocity you could just turn off the engines and cruise. Such a ship could not be able to land on a planet but it could remain in orbit and send shuttles for exploration. That ship would become an orbital station which could be used to extend the reach of other ships and so on...

Re:Fuel

[rmstar]

Seems very complicated. First of all, these fuel depots will be in different orbits, going at different speeds, and your main craft zips by at yet another speed. How are you going to align everything[?]

You use modern mathematics, and computing power. Transfers from one orbit to another, pace rendezvous maneuvers, etc. are mostly handled that way already. I don't think that is the obstacle. It rather is affordable propulsion. How many Saturn Vs do you need to lift the mass equivalent of one Saturn V to space? Way too many!

Re:We can get to Mars and baick.

[Rei]

Unless you're talking about building from lunar resources, you're talking about bringing payloads up from LEO, then from LEO to the moon, then from LTO to the lunar surface (in a non-crashing manner). WAY more expensive than building on Earth or in LEO. If you're talking about building from lunar resources, we're nowhere even near to that being economically justifiable due to manufacturing process consumables and the absurd cost of assembly/maintenance (because it's so expensive to get people to and keep people alive on the moon, your labor costs are correspondingly absurdly high).

Thank you Alan Finkel!

[hrimhari]

If it wasn't for your article, I'd have wasted the rest of my life trying to figure out how to get around things that today are believed to be impossible.

If only it was available earlier in human history, it would have given this extremely valuable service to our sad ancestors that wasted so much time coming out with impossible things like medicine, electricity, machinery, airplanes, genetics, quantum mechanics...

Re:You're forgetting about radiation

[Rei]

Thankfully, the solar radiation shielding part isn't too difficult, as the particles are lower energy. Keeping fluids at the skin and having a proper storm shelter should probably be good enough, and solar radiation shielding via electromagnetic deflection is also feasible. GCR is much tougher; even though the flux is lower, the energies are much higher and much more difficult to stop, whether using active or passive shielding. I think it's likely that with current tech, we'd have to accept our astronauts having significantly increased chances of cancer, infertility, etc.

Re:You're forgetting about radiation

[Rei]

Not at all. Space elevators are *extremely* sensitive to mass issues. In all practicality, an Earth elevator couldn't even support its own mass without an absurd taper factor (never minding the known other issues, such as induced harmonic oscillations).

Space elevators work great in sci-fi. Not so much in practice. If we ever want suspended structures on Earth, they're likely going to require active suspension, such as a Launch Loop.

Typical reaction

[evildarkdeathclicheo]

For every 1 engineer who figures out how to do something, there are 999 that like to yank their own chains by listing elaborate reasons as to why "it can't be done". It's these 999 that give the rest a bad name, and it's these 999 that are the first to get laid off and the last to get hired. It's easy to say it can't be done. Easy is boring. -W

A bunch of Yes and Nos...

[denzacar]

The challenge for space travel is to get buy-in from the broader population, and to do that it has to have the same visceral, senseless emotional response that warfare has. War is mate competition carried out by other means, and as such engages our deepest emotional responses.

No... not really.
A HUGE part of population is very interested in space travel COMPLETELY VOLUNTARILY. In fact, find me one kid who would not choose "Astronaut" as a profession if it was available.
You don't need it to be anything like war - just as colonists of the "New World" didn't go there because of some antiquated patriotic notion. They went to find a better life for themselves or to prove themselves. Fuck... many of them went to GET AWAY from antiquated patriotic notions.

As for "mate competition" - way off there. Wars are no longer fought in order to "git the'r women an' food".
Nor are they fought to "preserve the species" - wars are political tools. Have been since humans invented guns and by doing it made "warrior noblemen" obsolete.
And the quote goes "War is not merely a political act, but also a political instrument, a continuation of political relations, a carrying out of the same by other means."

While exploration is daring and dangerous, the vast majority of people can't participate in it in an active way.

Depends on your definition of "active participation".
By that same logic, people voting for their political representatives are not "actively participating" in politics.
Same as people who donate to various causes don't "actively help".

Give the humans a way to donate their time and money to such an endeavor. Hell... People donate both to deletionists at Wikipedia.

We sent 12 people to the Moon, compared to hundreds of thousands rotated through Iraq.

Besides obvious logistic differences here, most people that were sent to Iraq would actually like NOT to be there.
Those 12 were volunteers chosen from thousands others who would swap places with them in a blink of an eye if they could. Just ask the other 12 that went there without actually landing.

So from my point of view the problem with exploring other worlds is that we aren't doing enough of it to engage a large enough segment of the population.

"A large enough segment" is very much engaged - if by that you mean interested in space travel.
If you mean "sent to outer space" well... compared to your "engagement in war in Iraq" example - it costs a little more per person than a just some jet fuel, uniform, gun, ammo and a couple of months training to send someone to space.

If some country were to commit to militarizing the Moon, say, we'd see a vast increase in resources flung at space travel, and at this point I'm not sure that wouldn't be a bad thing. Even done by an organization as stupid and inefficient as any standing army, it would be cheaper and vastly less destructive than even a fairly tiny war.

Why militarized?
Look up at that Clausewitz quote again. It's POLITICS by other means, not war by other means.
Politics is also "Hey, let's go there TOGETHER". There really ARE friendly ways of competition available to humans where you don't even have to kill anyone.

Re:A bunch of Yes and Nos...

[radtea]

As for "mate competition" - way off there. Wars are no longer fought in order to "git the'r women an' food".

That whooshing sound you hear is my point passing far over your head. The fact that for some reason you have mentioned "food" in the context of mate competition proves it. War has nothing to do with food, and never has. It's just that really stupid people confabulate impausible bullshit like that to make war sound sensible, when it isn't, ever.

The "rational" motivation for Germany's attacks on its neighbours that started WWII was the need for land and peasantry to feed the German people. This was the NAZI dream: German imperial rule over Eastern Europe to produce food for Greater Germany.

Now suppose for a moment that there really was a looming food shortage in Germany. Here are two possible responses:

1) take a vast quantity of productive labour and other resources out of the economy and put them into killing people and destroying things so that you can repopulate and rebuild in the unlkely event you "win", and after having repopulated and rebuilt in the areas where you have expended enormous otherwise productive labour and resources to kill and destroy, force the people now living there to grow food for you while you continue to expend otherwise productive labour and resources on failing to control the subject population.

2) Invest in agricultural research and free trade to improve your own agricultural yields and import any shortfall from your more agriculturally gifted trading partners.

War has nothing to do with control of resources other than (supposed) mating opportunities. No species anywhere ever fights to the death over anything other than mating opportunities. In some species--including humans and and some varieties of deer and elk--control of resources is directly linked to mating opportunities, but those are the only cases where two individuals of the same species will ever fight to the death.

There is simply no reason to assume that it is any different amongst humans, given that war is always an economic loss: all parties are 100% certain to end up less well off than they would be had they resolved their differences without war. Mate competition is the only motivation that matters.

It is also a primary motivator in politics.

So unsurprisingly, I find quoting the dead German I was deliberately riffing of in my statement, "War is a continuation of mate competition by other means" enitrely unconvincing. Clauswitz knew nothing about evolution or economics, and as such he was incapable of appreciating that war makes absolutely no sense (nor do politics, in most cases, as the insane commentatry on Paul Ryan's statist, anti-libertarian health care proposals demonstrates.)

Re:You're forgetting about radiation

[Rei]

One of my favorite anecdotes from the Apollo era was the flashes of light they kept seeing. It was from radiation impacting their retinas.

Cataracts are very common among astronauts, especially the Apollo astronauts.

Re:Space Travel is a silly idea

[wjousts]

Two billion years is plenty of time to come up with interstellar travel, even without trying.

That may be, but if you take my answer in the context of the AC I was replying to, he (or she) seems to be of the mind that there is no point to it ever. I gave the most extreme example of why his (or her) proposal that it would be better if we all lived in the matrix (or some similar nonsense sci-fi fantasy) is flawed.

Re:Build on Earth, get fuel for trip home from Mar

[denzacar]

The above linked plans and costs are all WITH NASA spending ON NASA budget. Completely doable and affordable.

Problem is, they are neither pork nor do they need a bunch of pet projects.
You know... "ALL" they'd do is get a crew to Mars and back and let them do some actual scientific work while at it.
Perhaps pave the way for colonization and other useless crap that never got anyone reelected.

Re:Fuel

[Arlet]

Just launch all your fuel in low earth orbit, and attach it to the main ship. Much less hassle, and requires less fuel overall.

Then dump physics and chemistry

[plopez]

Go to more of a "faith based" space travel, not encumbered by "Science".

Well dur...

[DarthVain]

50 Years ago simply getting into space was seeming impossible. 50 years prior to that, flying through the air was a pretty big deal. Before that traveling over any distance not using horses was a big deal.

What the article is saying is using current technology, going to the stars is a bit, shall we say implausible. Mars is a stretch but we can probably do it if we really want to.

In a 100 years who knows what technology we will have at our disposal, heck if we are still around in 1000 years just imagine what kinds of technology we might use to explore.

That said, yes our current technology isn't there yet, and we would need something seemingly "magical" in order to make it possible. It will likely be easier to use robots and whatnot than to use Humans, as we have a host of biological issues that would need solving on top of everything else.

My current favorite magic technology is the development of a "cosmic anchor". This would allow you to stop in absolute space, while relative space simply revolves by. Using multiple anchor throws, and complex calculations of various systems and velocities and rotation, it may be able to navigate through relative space,

Or like many fictional accounts, there is always instantaneous travel.... that would be handy. Though my current favorite off shoot would be a quantum entanglement transporter, that much like that movie the Illusionist, it might destroy the old you (maybe), and recombine the new your someplace else. Another flavor I like (I believe it was in Old Man's War) is the simply warping to other parallel dimensions/universe that the differences are so minute as to not matter but someplace else.

There is of course the Hitchhikers Guide's Probability Drive also, or the David Brin Tandu drive of the same name, but not so funny outcomes...

A perfect example of trying to use today's technology and ideas for the future is The Forever War. You can see by the end of the book its pretty silly, particularly when you start messing about with relativity, and time. Essentially your technology will over time outstrip whatever current methods you are using. A Moore's Law sort of thing....

Re:You're forgetting about radiation

[khallow]

In all practicality, an Earth elevator couldn't even support its own mass without an absurd taper factor (never minding the known other issues, such as induced harmonic oscillations).

Unless you make it out of materials that don't have an absurd taper factor. Carbon nanotubes might be able to achieve the desired tensile strength to mass. Or you make some other tether structure that doesn't require the tensile strength of a space elevator (such as a sky hook).

Re:Build on Earth, get fuel for trip home from Mar

[Moryath]

Part of the cost problem is that it currently costs NASA roughly 12x more than it costs SpaceX to get payload into LEO (based on $450 million per shuttle launch). It's hard to do such a mission affordably when your costs are so obscenely high.

The joke there is the number of OTHER things NASA does on the same shuttle launch that nobody else in the fucking world can do. Satellite launches are a sideline; the rest is science.

Seems like the standard Retardican line always fails to consider this. NASA does the things that would never get done in their fabled "free market" because they're not "cost effective" at first to do - but when we count up how much we've benefitted from it since, it was obviously worth every penny.

Mining the Moon

[painandgreed]

The reason we would set up a base on the moon would be to mine it for water for fuel, radiation shielding for occupants, etc. If the amount of gear we'd need to mine water from the moon is less than the amount of water we need, then at a certain point it becomes more economical to ship mining equipment to the moon and get our water there. It is the large delta V for earth to space versus moon to space that would make it worth it. There is also the issue of mining the moon for things like iron and then doing manufacturing in space. However the research needed to be preformed to figure out if it is economical would probably be enough to continue mining the moon or get to Mars in the first place. It becomes a question of if we are just going to Mars to put up a flag, or if we are in the process of expanding into space. If the first, we might as well just go to Mars because that's all we want to do and it's all just wasted money anyway. If the second, the most of the ground work for going to Mars will have already been done. Even then, going to Mars is going to require more space research just to be able to do it properly and with a decent chance of success. I've seen some people complain because we're spending money on the ISS and talking about missions to the moon instead of spending it on a trip to Mars, what they don't realize is that going to Mars is going to require more money spent on the ISS as well as moon trips to develop the tech needed to go to Mars.

Re:Mining the Moon

[Nutria]

There is also the issue of mining the moon for things like iron and then doing manufacturing in space

Which is Not Trivial: explosives, rock crushers, dump trucks the size of a small house, smelters, forges, machine shops, the fuel to operate it all, etc, etc, etc.

Anyway, who makes spacecraft out of *iron*?

Re:Mining the Moon

[Plekto]

As near as they can tell, the material makeup of the Moon is identical to the Earth if you dig beneath the radiation and micrometeorite blasted surface. There should be everything we need to make aluminum and other materials there as well. Since it would be all underground, concerns about equipment would be fairly minor. You don't need massive equipment to haul dirt around when it's 1/6th the weight.

The main reason to build on the Moon vs in Orbit is the scale. It's hard to work in 0g and for these ships, we'd have to spend years building them. You can't just lift them into orbit unless we can make rockets that are 20-30X their current sizes. The Moon is far easier to deal with since most of the construction would be below ground and out of the way of radiation. There's also something to hold and press against as well, which makes mundane tasks like wrenching a bolt into place a trivial task versus a major problem in 0g. We could likely construct the ship in a fraction of the time. All we need is a huge cavern and a big set of doors.

Re:Mining the Moon

[Nutria]

While I completely agree with most of your last paragraph, the first paragraph and the last sentence of the 2nd paragraph grossly -- nay, stupendously -- underestimate how much capital equipment and energy is needed to perform heavy construction and large-scale excavation, mining, smelting/refining, forging and machining. For example, even on the Moon, 10 m^3 of ore is still 10 m^3 so you still need a big dump truck (eve if it's engine can be smaller).

Space travel isn't feasible.

[Animats]

(I wrote this on Slashdot back in 2003..)

The basic problem is that space travel with chemical fuels isn't feasible. You just can't pack enough energy per unit mass into the fuel.

Only by desperate weight reduction measures, resulting in incredibly fragile vehicles, is anything made to fly into space at all. The vehicles are almost all fuel. Pieces have to be thrown away after launch. Payloads are dinky for the size of the vehicle. Costs are insanely high.

It's been that way for almost forty years. It's not getting any better. No combination of parts will fix this fundamentally broken technology.

Space travel is like lighter-than-air travel. The technology has been around for decades, and it reached its limits a long time ago. It's possible to build vehicles. But the weight limitations are too severe for them to be more than marginally useful.

Space travel won't work until we get a better energy source.

That's still valid. Consider Apollo. They launched a 50-story building and got a minivan back.

Suborbital flight takes far less energy than reaching orbital velocity. What Virgin Atlantic is doing is comparable to Alan Shepard's suborbital flight atop a Redstone ICBM in 1961. It's a roller coaster, not space travel.

Nuclear rocket engines would work, and were tested in the 1950s. That solves the mass ratio problem. But they're rather messy.

Re:Some of the tech needed for Mars is 19th centur

[metamatic]

The challenge for space travel is to get buy-in from the broader population, and to do that it has to have the same visceral, senseless emotional response that warfare has.

So if you gave people a choice between (a) Mars mission and (b) current wars in Iraq, Afghanistan and Libya, you think the majority would choose (b)?

Maybe I'm hopelessly out of touch, but I didn't think war was actually that popular with the broader population. Only with politicians.

Re:We can get to Mars and baick.

[Brucelet]

I think I'd want to see a Mars sample return mission before saying all technology is proven. We haven't yet demonstrated that we can send payload to Mars efficiently enough that something can be launched from the surface and sent back to Earth.

The moon is made of rocket fuel.

[blair1q]

The moon is made of rocket fuel.

Look it up.

I was thinking of writing a sci-fi story

[JTsyo]

In it Earth is ruined and humanity is taking a last gamble at survival. Robots are send out to terraform planets with AIs in charge of the mission. This is followed up by humans but as embryos. When the destination is reached, they would be placed in artificial wombs and then raised by robot care takers for the first generation. The main part of the story would be how that society turns out and how people that are raised by robots designed to mimic parents. I can't really think of plot elements to make the story interesting yet.

There are many options that we would have imployed if we wanted to colonize other star systems. it's just that the drive for it doesn't exist.

Re:I was thinking of writing a sci-fi story

[orkysoft]

In Alastair Reynolds' Revelation Space series, this is glossed over in the backstory. These people became psychopaths.

Re:We can get to Mars and baick.

[aix tom]

Well, let's hope the Russians make the next Baby-Step in that direction with Fobos-Grunt (At least Mars-Orbit and back).

Re:don't believe the Hype

[aix tom]

iRockets only work in LEO, unless you jailbreak them. Which will probably be more complicated than building a functioning Stargate.

Why so Biological?

[Baron von Daren]

There is a decent chance we will, as a species, shed our mortal coils before we overcome many of the biological/technological hurdles to long range space travel. Assuming the transfer of human consciousness to a technological substrate is not impossible (or ostensibly impossible) due some heretofore empirically unseen factor such as the ‘spirit’ or higher dimensionality of ‘mind,’ it seems inevitable that humans will evolve into a technological speciesthat is if we survive at all. Once we are no longer biological, many of the difficulties currently inherent to space travel drop away. We would have virtual worlds in which to live while we travel, we could more easily shield our ‘bodies’ from cosmic radiation, and we would require far fewer hard resources to sustain both our consciousness and our virtual worlds. Now I don’t believe I will live forever because the technology to download my conscious is just around the corner. I think that technology is some ways out and almost certainly beyond my lifespan. If consciousness is ultimately just data and computational power, however, there doesn’t seem to be any hard reason why it can’t be ported to a different kind of hardware. I hate to even suggest the idea because I general take great pleasure in dashing the quasi-religious zealotry of friends who are convinced they will partake in a digital-rapture, as it were, and live for some incredible span of time via a technological apotheosis, but the fact remains that we will probably obtain the ability to leave our bodies behind at some point in the next 200 years. PS I’m not anti-religious, but that’s a whole other discussion.

Re:Some of the tech needed for Mars is 19th centur

[mcmonkey]

The challenge for space travel is to get buy-in from the broader population, and to do that it has to have the same visceral, senseless emotional response that warfare has.

So if you gave people a choice between (a) Mars mission and (b) current wars in Iraq, Afghanistan and Libya, you think the majority would choose (b)?

But that's not the choice we face. The choice we have is not between you go to (a) Mars) or (b) Iraq.

The choice is, you pay for someone else to go to (a) Mars or (b) Iraq.

Sadly, more people picked (b).

Closed Ecosystem

[HiThere]

The only intractable problem about a Mars colony is a closed ecosystem. And if we can solve that, I'm not sure that a planet is the right place to aim for. Asteroids look a lot more promising. (Though you'd want 3...a carbonaceous chondrite, a metallic one, and a head of frozen gases. If you're far enough out (the outer asteroid belt?) you might be able to find all three blended in one body. Otherwise you'll need to catch at least the frozen gasses item and fetch it.)

LEO and beyond

[geek2k5]

The biggest technical problem is getting to Low Earth Orbit. Right now it is too expensive, though people are working on solving that.

The biggest overall problem as I see it is the socio-cultural approach we are taking with regards to space.

Back in the 1930's space flight was science fiction, though a few people like Goddard, Tsiolkovsky, and Oberth had been working on the technical aspects for a few years. People dreamed what it would be like to go into space and came up with some ideas on how to do it and what they might face. But it was just a dream that needed technology to make it real.

In the 1960's science fiction became science fact as the Space Race came into play. National pride and national security demanded that the money be spent on space. It got us places, but not cheaply. We learned a lot about what to do and what not to do. The dream was alive.

Since then we've been coasting, making little steps and sometimes stumbling. Space flight has become a 'so what' type of thing for a lot of people for a variety of reasons. It was also a fairly restricted 'club' limited to professionals and a small number of multi-millionaires. But the dream continued to live on and a few hundred ambitious people made it into space. They had to work hard to get those seats though.

In the not too distant future, as a result of private enterprise getting interested in space, 'normal' people will be making baby steps into space. These baby steps are much like the 'barnstorming' flights where pilots sold airplane rides. You went up, you came down, and you talked about it to all your friends. That creates an greater cultural awareness of what could be done with airplanes and it will do the same with suborbital space ships. And if people like Rutan and Branson can make a profit at it, an greater economic awareness will develop.

When the ball gets rolling in the suborbital area, people will start looking at orbital flights with a greater degree of seriousness. Once you reach orbit, you're halfway to everywhere.

Famous Slashdot Sig

[wwphx]

"A polar bear is a rectangular bear after undergoing a coordinate transformation."

My wife, PhD in physics/astrophysics, almost bust a gut when I told her that one.

James Hogan - Voyage from Yesteryear

[geek2k5]

You might check into James Hogan's book "Voyage from Yesteryear."

A robot probe is sent to a nearby star with a habitable planet and the equivalent of embryos. Robot caretakers raise the children and help with the colonization of the planet in a cultural vacuum that doesn't transmit a lot of cultural bad habits like racism and classism. (This is a minor part of the story.)

Back on Earth World War III comes and goes. A much larger spaceship is sent to the colony to take charge of it for the 'good guys,' arriving a few years before two other ships from competing factions of 'bad guys.' A culture clash happens, with the robot raised types countering the 'good guys.' (This is the bulk of the story.)

The robot raised types, and the kids they have, have a lot more going for them, intellectually and socially, than many of the 'good guys.'

It is an interesting story.

Re:James Hogan - Voyage from Yesteryear

[JTsyo]

Will have to look into that book once by reading list clears up.

oh, nonsense

[t2t10]

The entire article assumes a 1960's approach: launch everything from earth with rockets. That's stupid. Its focus on chemical propellants is even sillier because nuclear propulsion is arguably already a "current" technology.

There are lots of technologies that you can use to get things out of earth's gravity well, including launch loops. There is lots of mass out there that you can use as a propellant and for other purposes. For propulsion, fission is close to ready, fusion is feasible, and even something like antimatter propulsion doesn't involve any new physics, just engineering for scaling up the antimatter generation and storage.

If we want manned spaceflight and colonization, we need to do several things. First, we need to stop wasting money and resources on the current manned space program and instead focus on extensive robotic exploration of the rest to the solar system to know what's out there and how we can take advantage of it. Second, we need to start investing in new launch technologies that don't use rocket propulsion. Third, we need to aggressively pursue the engineering behind fission, fusion, and (eventually) antimatter propulsion.

We need aliens

[Xaedalus]

Simple as that. We need definitive proof of sentient, space-faring extraterrestrial life. Get that, and you'll have your visceral response in a hurry.

Re:Forget it? I don't think so!

[Intrepid imaginaut]

What is there on the moon or Mars to make it worth going there. Why should anyone want to live there?

Probably quite a bit, but we probably won't know till we get there. :D I'd be a lot more interested in the asteroids as an intermediate step, literally trillions of dollars worth of raw materials just floating around out there, and a gigantic nuclear furnace just pouring out free energy to help you process it right behind you. Welcome to the post scarcity society. Once we have that licked we can swan about planetary gravity wells on a whim, probably even create macroengineered catapults to make insterstellar travel more accessable eventually too.

Oh and your going to live the rest of your life in this box, you will never see the destination, nor will your children, their children, their children's children, and likely ten more generations after that.

Most people spend most of their lives in a tiny geographic area anyway, the only difference is you couldn't take holidays.

Re:Build on Earth, get fuel for trip home from Mar

[khallow]

The joke there is the number of OTHER things NASA does on the same shuttle launch that nobody else in the fucking world can do. Satellite launches are a sideline; the rest is science.

Perhaps you ought to first read what Space Shuttles actually do. I consider the record an embarrassment to the US and its space efforts.

Satellite launches are the primary value of space development right now. Space science is a great way to soak up OPM because it has vague goals and be said to succeed no matter what the outcome or how much was spent on it.

Seems like the standard Retardican line always fails to consider this. NASA does the things that would never get done in their fabled "free market" because they're not "cost effective" at first to do - but when we count up how much we've benefitted from it since, it was obviously worth every penny.

"Worth every penny"? No effort to develop commercial activities in space. That right there indicates NASA has squandered its money. No manned activity beyond LEO since Apollo 17. A long series of one-off unmanned probes.

Get rid of rockets.

[dicobalt]

They explode, they are unreliable, they are slow, they have to be really huge to move only a small amount of mass, you need an army of PhD's to keep just one of them under control, and they smell like pee. Frankly most of the space programs money should go to projects like the LHC which will eventually solve actual problems which will enable true space faring ships and energy production facilities. Rockets are for people who think small.

The real limit?

[nbohr1more]

I believe I've read that the real speed limit is 100 kilometers per second. Any faster any the electron-shell stability of most atoms will become significant enough to induce heavy thermal increases.? (Essentially, you will cook as if in a microwave oven,,,) As far as "going fast" is concerned, the easiest solution would be to build a large mag-lev train in space. It would be like a large particle accelerator so you could get the ship up to just below the speed of light as it circled around, The problem, of course, is the 100kmps limitation as originally stated (if true)... Well, the other problem is "stopping"...

Seriously???

[dsdtzero]

3 words:
Orbiting fuel stations (I'm sure someone mentioned this earlier but I didn't see it in first 100 postings)

Think of how absurd it would be if trucks had to deliver fuel to us at out homes for our round trips to work. There are hundreds of solutions to this problem its just a matter of will (and $$$). I'm frankly surprised this made it on the /..

There are more fundamental limitations to drilling past the mantle than this. Furthermore, I think exploring the oceans would be a much better place to spend this type of money. Colonize the ocean!

Re:Fuel

[TaoPhoenix]

I don't quite buy "complicated".

The simple explanation is "Play a game of Asteroids and go get it", the fancy phrasing is that the adjustments needed to get the boosters are still less than 1 big tank from earth, because the bad part of them is getting them out of the main earth field.

I still believe we're too busy squabbling and not trying hard enough like we were in the 1960's when we felt it counted for real. Now we have the comps but we got lazy.

And in news from 150 years ago...

[PhunkySchtuff]

In breaking news from 150 years ago: "The clash of two titans — physics and chemistry — are major barriers to human heavier than air flight, and may well make it impossible ... at least with current technologies."

Re:Some of the tech needed for Mars is 19th centur

[metamatic]

But that's not the choice we face. The choice we have is not between you go to (a) Mars) or (b) Iraq.

The choice is, you pay for someone else to go to (a) Mars or (b) Iraq.

No, the latter is exactly what I meant. I didn't mean each individual taxpayer would be given the choice of going to Mars, don't be ridiculous.

Sadly, more people picked (b).

Really? I don't remember any kind of referendum on the topic.

Re:You're forgetting about radiation

[Plekto]

Possibly. But it's much easier to make a body-sized capsule essentially radiation-proof compared to the entire spaceship. There's also the consumables and waste that you don't have to deal with. And of course, very little aging. Radiation exposure might still be a problem, but it would be far less than in a normal spaceship. Using this for long distance trips would mean less exposure the more distant we traveled from our Sun.

It's not perfect, but it's far better than letting people rot in a tin can for months or years.

Re:How about Space Elevator?

[DanielRavenNest]

A full Earth surface to GEO space elevator is not possible with current materials. But you can certainly build a partial one with what we have now. And a partial one is still highly useful. For example, one that reaches 30% of the way down from orbit, and 30% of the way up from orbit can be done with current materials. That would make the job of any vehicle coming up from the ground much easier. At the other end, 30% above orbit velocity is nearly to Earth escape (41% is escape).

A 30% space elevator works out to a cable stress of 300 G-km. In other words the same as hanging a 300 km long cable at one gee under it's own weight. For carbon fiber, that works out to 5.3 GPa, which strength is available. In a real system you would taper it somewhat from center to tips, which lets you use lower stress and get realistic safety factors.

Re:You're forgetting about radiation

[dragonhunter21]

True enough, but my point about the radiaiton doing more damage in stasis is based upon the assumption that cellular repair processes (that would otherwise mitigate radiation exposure) are slowed to a crawl or halted along with the rest of the body.

Think of, say, a spaceship on a 50-year journey experiencing around 19 microsieverts per hour. If those people were awake, that would be a dose that could cause problems, but it would likely be slow enough that the body would repair the damage. If the crew were in stasis, however, it couldn't repair. The total dose for that trip would be >8 sieverts, enough to cause death. When the person woke up, it'd be like they got a full-body one-time dose of 8 Sv.

(If I'm wrong, please tell me- but this makes sense to me. Still not discounting stasis, though, god knows I wouldn't want to be awake for a 50-year space journey)

Re:You're forgetting about radiation

[Plekto]

The shielding on the "pod"(or whatever shape it takes) could be shielded to 10-100x the extent of the rest of the ship, so they'd only have a moderate dose. Also, for deep space missions, the amount of radiation that they would be exposed to would of course decrease the farther that they got from our Sun. Also, because of their condition, they could sustain longer periods of acceleration, which means a slightly shorter trip (accelerating at 2G would be nearly impossible to try to live a normal life under, as an example). It's really the only viable option unless we find a miracle method to cross space quickly.

Of course, there would be a potential problem with the rest of the ship itself being dangerously radioactive after that long.

Re:You're forgetting about radiation

[Rei]

That's the problem -- no, they don't. Look at how much the Edwards elevator was estimated to cost. That involved assuming a bulk ribbon of 100+GPa. The strongest *individual* SWNTs ever measured thusfar were a mere 62GPa. That's a huge difference in terms of taper factor -- and that's for the *strongest* *individual tubes* ever measured. Bulk fabrics are going to be far weaker than their strongest tubes.

Just from this alone, a space elevator is a nonstarter on Earth. Do we even need to get into how inefficient they are?

Sky Hooks are hugely problematic for many reasons that aren't even worth getting into here. Just go with actively suspended structures. There's no good reason not to. They're stable, highly efficient at transferring energy to spacecraft, readily buildable with current materials, and the maintenance energy costs are proportionally insignificant.

Why go?

[ResidentSourcerer]

1. Resources. No it doesn't take a huge number of people. But calculate the value of a cubic kilometer of nickle iron. I'll allow you to ignore the platinum group metals in your calculations. The introduction of that much platinum would crash the market.

2. Energy. The sun shines all the time. Building flimsy mirrors to concentrate it is easy. Can be used as raw heat to melt rocks, or converted into microwaves. If microwaves don't turn out to have unintended consequences this may be the easiest way to wean ourselves off of oil.

3. Vacuum. There are a whole bunch of processes that having unlimited cheap vacuum makes possible.

4. high energy + vacuum allows easy element separation by mass spectroscopy technology.

5. Microgravity. Whole bunches of new materials may be possible.

6. Dinosaur killer interception. Once we are in space to stay, we've got a much better chance both to spot and to stop the next big rock.

Population pressure may encourage some people to live in space, but it is unlikely that people will move faster than they reproduce. (Very few emigrations reduced the population of hte source country.) It is far more likely that initially people in space will be long term contracts similar in nature to peopel working on arctic mines or oil fields today.

However cramped living facilities are entirely a result of having to lift all the mass out of Earth's gravitaional well. The slag from refining can be readily blown into glass foam, which is both a very good insulator, and strong enough to be a component in habitat construction.

Re:Space Travel is a silly idea

[Tom]

I agree. But then again, I don't take the GP serious in that. Because, you know, his "not ever" will die with him and the next generations will make up their own minds about it.

"never" is so unlike what the word means when a being with a ~100 year life-span talks about spans of millions and billions of years.

Re:You're forgetting about radiation

[khallow]

The strongest *individual* SWNTs ever measured thusfar were a mere 62GPa.

Theoretical is somewhere around 120 GPa and multiwall nanotubes seem to do better than single wall. We'll just have to see whether 100+ GPa in a carbon nanotube composite is achievable or not.

Do we even need to get into how inefficient they are?

Sounds like we do. They're more efficient than chemical rockets since one can use more efficient propulsion (such as electric propulsion) to keep the counterweight in orbit.

Sky Hooks are hugely problematic for many reasons that aren't even worth getting into here. Just go with actively suspended structures.

How about we go with sky hooks? Actively suspended structures have a huge problem. They fall down when the control system fails. I see it as much more likely than any similar failure mode on a sky hook (such as breaking the tether at the midpoint, so that half goes outwards and the other half deorbits onto Earth somewhere).

Re:**CRACK*** *POP* *CRUNCH*

[uninformedLuddite]

To quote Einstein: "Whoever undertakes to set himself up as judge in the field of truth and knowledge is shipwrecked by the laughter of the Gods."

Unless of course they are too busy playing Craps to be paying attention

Re:You're forgetting about radiation

[WalksOnDirt]

They're more efficient than chemical rockets since one can use more efficient propulsion (such as electric propulsion) to keep the counterweight in orbit.

The counter weight will stay there without any propulsion because centrifugal force will keep it there. (We live in a rotating frame of reference, so of course there is centrifugal force.)

How you are going to power the elevator car is an interesting problem. I don't think HVDC will work very well for 14,000 miles, though I might be wrong. Maybe they could be nuclear powered, or we could try beaming power to them. I'm not sure any of these is satisfactory.

Re:You're forgetting about radiation

[khallow]

The counter weight will stay there without any propulsion because centrifugal force will keep it there.

If you bring a lot of mass out of Earth's gravity well, the counterweight won't stay put. It oscillates with the amplitude of the oscillations building up as more mass is brought to space. Eventually, it'll have enough energy (assuming the cable doesn't break first), for the counterweight to move closer to the Earth than the geostationary radius with collapse of the system following. A propulsion system on the counterweight would dampen these oscillations, effectively creating a system where mass is brought to space as if it were on a rocket with the effective delta v of the propulsion system.

How you are going to power the elevator car is an interesting problem. I don't think HVDC will work very well for 14,000 miles, though I might be wrong. Maybe they could be nuclear powered, or we could try beaming power to them. I'm not sure any of these is satisfactory.

Beamed power seems the likely choice. A slow system might use solar power on the cars themselves.

The limits we face

[readin]

What are the limits we truly face in the long term?

How much energy is hitting the earth from the Sun? How much energy is available from the Sun to a ship in space? How much energy is there on earth (from every source including geothermal (there is a lot of heat under the earth's crust) and nuclear power?

What are the limits of genetic engineering (maybe humans of today can't travel far, but what about humans of the future?

There are limits - the earth is pretty darn small and Space is pretty darn big. When you hear those comparisons "peanut in Reading and a small walnut in Johannesburg, and other such dizzying concepts" it seems amazing that a bacteria from the peanut could find its way to the walnut. Apparently we've done it, but how much of the peanut did we destroy in process? How many times can we repeat it? And can we find find a place to go to that makes the trip worthwhile?

Re:You're forgetting about radiation

[WalksOnDirt]

If you bring a lot of mass out of Earth's gravity well, the counterweight won't stay put. It oscillates with the amplitude of the oscillations building up as more mass is brought to space. Eventually, it'll have enough energy (assuming the cable doesn't break first), for the counterweight to move closer to the Earth than the geostationary radius with collapse of the system following.

There is a limit on how much you can move up an elevator without it coming down, but if you stay below that limit you never need any propulsion. When the counterweight is pulled off vertical it pulls momentum from the Earth to try and straighten out. The Wikipedia article covers this.

We need to...

[bobs666]

1) Clean up the space debris. so we don't get hit by it.

2) Build a space elevator (bean stock). Rockets are just to expensive, given the amount of mass we need to lift.