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The G forces from acceleration are just increadable, artillery shells with terminal guidence are do-able;
Laser-guided Copperhead artillery shells withstand 10,000 G.
Experimental circuits developed for railgun launch withstand 100,000.
  To get to orbit I doubt that there is any propellant that would build enough pressure before the projectile left the tube; even if there was there would be no tube that could contain it.
If there was a material that would work for the tube, it probably would be better used as an elevator ribbon. Stapping a rocket motor onto the base of the projo, just means more tube preasure to get the same muzzle velocity.

This is the basis for the argument for CATs (Cheap Access to Space) and
http://www.space-frontier.org/Projects/CatsPrize/
various legislative pushes and at least a couple of billionaires (including Jeff Bezos of
Amazon.com) putting a lot of money into this (perhaps as businesses, but
essentially still billionaire hobbies). While I wish them well, I think
this approach towards space settlement is misguided. Let's work the
numbers.

The USA has about two million millionaires. There are many more elsewhere.
http://news.nationalgeographic.com/news/2003/07/07 11_030711_money.html
"In total, there are an estimated 7.3 million people in the world whose
assets--excluding their home--amount to U.S. $1 million or more. Behind
Europe, North America has the second highest concentration of
millionaires at 2.2 million. The Asia Pacific region accounts for 1.8
million. Latin America and the Middle East account for 300,000 each, and
Africa accounts for 100,000."

At current launch costs of $10000 per pound, to put a 150 pound adult
(me on a starvation diet for a couple months!) would be about
$1,500,000, or $6,000,000 for a family of four. Now that amount of money
being paid is well within the reach of hundreds of thousands of people
if they liquidate all their assets -- homes, stocks, retirement
accounts, and so forth. Now if you could guarantee that they and their
children would have a better life living in cities in space, then some
percentage of them might well do that. The problem as I see it is, we
can't guarantee that right now. The other problem is of course, there is
no place to live right now for hundreds of thousands of people showing
up in their underwear and starving with no shelter or clothes or food or
air or water or other goods for them.

One solution is to pursue the 1980s NASA vision
http://www.islandone.org/MMSG/aasm/AASM5A.html#5a
of first putting
automated factories on the moon (or at asteroids) and using robotics
(and teleoperation) make space settlements complete with food, water,
clothes, etc. for when these people show up. It would in theory only
take one Apollo-type launch to the Moon or an asteroid
with the seed of an automated
factory instead of a LEM to start the process rolling, and that would
have an up front cost of a few billion dollars or so -- far less than
the total launch costs for all the people. The factory could also carry
out putting up mass drivers etc. to realize Gerry O'Neill's or
J.D. Bernal's vision of building
near earth habitats from lunar or asteroidal resources.

So, as I see it, launch costs are not a bottleneck.
So while lowering launch costs may be useful, by itself
it ultimately has no value without someplace to live in space.
And all the innovative studies on space settlement say that space colonies will not be
built from materials launched from earth, but rather will be built mainly from
materials found in space.

So, what is a bottleneck
is that we do not know how to make that seed self-replicating factory,
or have plans for what it should create once it is landed on the moon or
on a near-earth asteroid. We don't have (to use Bucky Fuller's terminology)
a Comprehensive Anticipatory Design Science
http://www.bfi.org/node/387
that lets us make sense of all the various manufacturing knowledge
which is woven throughout our complex economy (and in practice,
despite patents, is essentially horded and hidden and made proprietary whenever possible)
in order to synthesize it to build elegant and flexible infrastructure
for sustaining human life in style in s

You're correct about Ukraine. It was Kahzakstan that the loan was obtained from in exchange for the shuttle.

Neither US, nor any other country pumped any significant $$$ into Russia.

Nonsense. Ever heard of Boeing Sealaunch? (Zenit 3SL boosters.) How about Proton launch services provided by Lockheed? Not to mention all the Progress and Proton flights that the US has paid for in the construction of the ISS.

There is PLENTY of US money being shunted into Russian space ventures.

Bodies in outer space are not supposed to be used for millitary purposes. Interesting that this is essentially a 'territory' which is not a physical body.

http://www.islandone.org/Treaties/BH766.html
http://www.spacelawstation.com/international.html

I always thought that outer space would at least prevent people from contesting territory, since area, particularly off of the major planets, seemed so vast relative to the cost of putting things up there. I figured scarcity wouldn't be a problem and the territorial boundaries that nations are based on might be partially undermined.

I figured space would be libertarian.

I guess this just re-emphasizes that even in space there are scarce resources which people are going to end up fighting over, and which will necessitate extending national power into outer space, in order to enforce any claims on territoriality.

They really take the scenario to the extremes, and the focus is self-replicating nanotechnology rather than robotics, but it's a very interesting read.

Advanced Automation for Space Missions

Here is a good synopsis (the study itself is rather lengthy).

Now... if NASA had only sent a rover to Mars that could replicate itself... :-(

This *isn't* so far fetched. NASA published a report 25 years ago on this topic. [Advanced Automation for Space Missions, Proceedings of the 1980 NASA/ASEE Summer Study.] They were just using macroscale technologies rather than nanoscale technologies.

Just like any other rocket, the thrust comes from the thermal expansion of gasses pressing against the sail-shaped surface. The major difference in this design is that the energy to heat the gasses comes not from chemical, nuclear or solar power onboard the craft but from on off-board source on the ground. It is functionally identical to the Laser Launch concept.

This system would work like a cannon, accelerating the craft within the span of hour or so to the orbital velocity of its target. Then the craft would coast up to that orbit like a cork bobbing to the surface of the water. It would arrive at that orbit with zero velocity relative to its target. In order to make an orbital insertion, it would require only relatively small, onboard maneuvering thrusters .

Of course, since the energy source is back on Earth, the same system could not be used for a return flight without building a microwave generator at the target.

Long term, you could set up a type of railway system, with generators around all the planets which could cheaply shoot packages back and forth.

Some sort of series of shaped, small, explosions every tenth or every second? With some sort of backplate to protect the ship?

N.B. Not recommended for regular use on the surfaces of inhabited planets. You thought diesel fumes were bad?

Step 2: Along with a number of solar power satellites at the Earth-Moon L4 and L5 points, build solar parasols at the Earth-Sun L1 point. Make enough of them to block 1-2% of the solar flux.

Step 3: Profit!

Clark didn't invent the idea. see

THE SPACE ELEVATOR:
'THOUGHT EXPERIMENT', OR KEY TO THE UNIVERSE?
by ARTHUR C. CLARKE

http://www.islandone.org/LEOBiblio/CLARK1.HTM

I consider it just about any computer/computer information transfer that allows near-real time reading/posting/replying (as Usenet certainly did)

Yes, a single Mars mission would be more economical as a sling-shot journey. But, we can assume more than one mission would be necessary in order to gain any worthwhile scientific understanding of the red planet.

A Moon base could expedite multiple missions by providing training/living facilities, valuable extraterrestrial storage space(for fuel, oxygen, supplies), and a sixth of the gravity. Also, the possibilities for non-Mars related missions associated with a Moon base are awesome: larger, further reaching telescopes, hydrogen propellent via polar lunar ice, communications relay via microsatellites... For more info: some NASA site.

On a full tangent, current technology is not feasible for multiple missions to Mars: it is obvious that we need to use more efficient long-distance propulsion systems. Let me know what you find...

Here's an article on the subject of Alcubierres Curve;

http://www.islandone.org/Propulsion/Alcubierre.htm l

The reason private industry isn't in space is that there's no money in it. Until that changes, we'll do nothing but probes - and no one ever comes up with an idea for making it profitable.

Actually, it's not that there's no money in space. It's that there's a chicken and egg issue. Why would anyone invest in space before there's an economic incentive? But who's going to create an economic incentive if there's no money in it?

That's where NASA comes in. NASA should be using large (and comparatively cheap) boosters to send hundreds of metrics tons of space station and workshop equipment into orbit. Once they have the ability to build many things in space (and launch from a decent orbit *grumble*), then the possibility of mining becomes a reality. I don't know of a single investor who wouldn't jump at the chance of bringing back precious metals at a high profit margin.

No, you don't need the level of industry we have here on Earth. (At least not initially.) More than enough can be done with standard workshop equipment. Drills, laser cutters, PCB printers, plastic molding, etc. all exist in fairly small machines. The tradeoff is that your production wouldn't be very high until better factories are built.

Now imagine this. On Earth, 3D printing is a very difficult and expensive process. Gravity ensures that stability is a key problem during the printing process. But what if we were to 3D print in freefall? With no forces acting upon the object, many more materials and shapes could be printed. Imagine if robots could be used to "print" an entire space ship! You just can't do that on Earth.

Two words. Breeder reactor.

Two words: Doesn't matter. A breeder reactor increases the amount of energy you get out of a given amount of materials. It does not, however, magically create materials out of non-nuclear fuels. It really amounts to further enriching existing fuels. Yes, it will extend the time. No, it will not extend it indefinitely.

100% pure pie-in-the-sky. Even if we could magically tap huge amounts of solar power, where do you put the antimatter once you've created it? And once you have it, so what?

There's no "magic" to tapping the sun. You need heat on one side, and cooling on the other. That's how thermal generators work. My original plan was to put a station at about 0.1 au. Speaking with engineers about the issue, they explained that using mylar mirrors would provide you with the same amount of thermal energy at a much greater distance. There's an interesting discussion on this here.

BTW, you may find this, this, and this very interesting. Yes, that's right. NASA plans to launch an antimatter powered space craft!

Or better yet, power the sucker with a microwave beam.

This website has a list of many advanced propulsion technologies under devleopment by JPL. Considering that we are using chemical rockets which have been known about since the 30's it's good to see that people are looking into new propulsion tech. These systems, some of which can reach the speed of light, include Advanced Chemical Propulsion, Nuclear Propulsion, Antimatter Propulsion, Electric Propulsion, Micro Propulsion, Beamed Energy, Sails, Gravity/AeroGravity Assist, Chemical and Electromagnetic catapults, Tethers Skyhooks and Towers,Extraterrestrial resource utilization,etc.

...it is the only technology now in existence that can one day take us to the stars.

Orion can take us to the stars, and it can be done with today's technology, not something that's just starting to enter the very earliest test phases. But it's nuk-yu-ler, so it doesn't count.

Instead of a 2 year timeout while the Shuttle is being revamped, I think we need to take a 10 year timeout until new launch systems are invented.

Here are the technologies I would invest in:

Any of several forms of launch assist, most likely Magnetic Rail. Any other technology would benefit from having this as a virtual first stage. Find the ideal location and buy the land -- DO NOT LEASE. We could probably build it in America, but why be trapped long term with less than ideal initial launch orbits. To be really radical, make it accessible to all nations, maybe build it as a coalition of the gravity well escaping.

Scram Jet and VASMIR, lets throw bucket loads of money in those directions.

Ditch the Space Elevator (at least for now), concentrate on something that could really be built, and that would be a "rotovator"

For items like oxygen, water, propellant, food -- fire them into orbit with a cannon. Massive G-Forces will not hurt them (though it might over tenderize steaks if that's the kind of food your sending up). This is really-really cost effective. Iraq was constructing a cannon capable of hitting Israel, it's just a matter of scale

Put any two or three of these together, then manned space flight begins to make sense

Following up to myself: here's a link to a page about a variety of tether-based designs and experiments: Advanced Propulsion Concepts.

Maybe we can travel around ON our weapons, that way fusing two ideas in one!

Ever heard of Project Orion?

A true Dyson sphere is not solid. It's a shell made of many independently orbiting bodies arranged in depth.

There would be no buildup in pressure. In the original notion, the energy is re-radiated outside the shell in the form of heat after the energy has been "degraded" by use.

The orginal paper that suggested the idea.

Unfortunately, the drawbacks of airbreathing appear to outweigh the advantages, at least for vehicles intended to put objects into orbit.

The problem is that a scramjet trades a dense propellant (LOX) for more of a low density propellant (LH2). As a result, the propellant tanks on a scramjet vehicle would end up being larger (and heavier) than those on an SSTO rocket with similar payload. LH2 is also much more expensive than LOX, so your propellant costs go up (not that propellant cost is currently important, but your vehicle is also in a more aggressive thermal environment so it to will be more expensive.)

Worse, the effective Isp of a scramjet (after you take into account drag and gravity losses due to its lower acceleration) ends up being little better than the rocket. See Henry Spencer's comment on this.

About the only place scramjets may make sense is in hypersonic cruise missiles. The US military has a scheme for using hydrocarbon fuels, converting these fuels into hydrogen + CO in flight by partial combustion with a portion of the incoming air (that portion is slowed to a stop by a conventional ramjet inlet, with the fuel being used to keep the air relatively cool and the inlet from melting.) The H2 + CO + nitrogen is then injected into a scramjet for complete combustion.

Try this:

Rotovator

I'll vote for the first president who promises to fund research in Lofstrom Loops or the like...

If I understand them correctly, Lofstrom Loops are active systems. If the ground station control (or power) fails, the circulating mass impacts in the vicinity of the ground station (i.e. the spaceport) over the period of one loop cycle. Something between a large bomb and an extinction event, depending on the size of the device. Damage can be mitigated somewhat by dumping the upbound part of the mass into space, but the downbound part is already going to toast somebody. (Please correct me if I'm wrong.)

I prefer the Rotovator - though I prefer the form where it only dips into the stratosphere to rendevous with an aircraft. Much less mass, and only an ill-timed cable break dumps any of it on an earth-intersection orbit. Total control failure just means the orbit starts to decay very slowly, and I think you can arrange it so the decay takes the device UP rather than impacting the atmosphere and or ground.

Solid fuel and liquid, throttleable oxidizer. Restartable, too. Read all about it here.

You mean Project Orion? Interestingly, the British Interplanetary Society studied an updated version called Project Dadelus that used much smaller fuel pellets, exploded them in a reaction chamber, and controlled the thrust much better than the Project Orion plans.

I think the bigger problem is that people don't really unstand that LEO isn't really very far into space. (no flame intended, really)

Sorry I couldn't find better numbers, but your 90% is way off. Here's the best quote I could find.

Contemporary launch vehicles have launch costs of $10,000 to $20,000 per kilogram of net payload to low Earth orbit (LEO) and $60,000 to $120,000 per kilogram of net payload to geosynchronous Earth orbit (GEO).

It's probably cheaper if you don't "stop" in geosynchronous orbit, but how much is beyond my knowledge.

The F-22 is designated to replace the F-16 in whole. The JSF/F-35 is designated to replace the F-15 and Harrier. Both are completely new designs, with the F-22 incorporating stealth technology (better than the F-117 from what I understand, while having better handling capabilities than any other production plane ever) and the F-35 having a variety of features -- mainly being "cheap" for a modern day military jet and an option for VTOL (required by the Marines). If you want nifty new tech, take a look at the F-22 -- supercruise is significant.

However, for better or worse it seems like we've reached the end of the "bigger and faster" era, and the era of radically new propulsion technologies.

Ramjets and scramjets are perpetually on the design and testing boards... and hey, there's always Project Orion!

If you want to lament faster, then note that we haven't produced any planes that can go faster than the SR-71. Unless you believe the sketchy reports about Aurora.

If you want to lament bigger, then just stop it right now. Airbus's A380 will have a passenger seating of 550 -- larger than the old 747 -- with a greater range (8000 nm vs 7670 nm) and greater speed (0.89 mach vs 0.855). And the sucker weighs over a million pounds on takeoff...

Boeing just announced their intention to build the 7E7 which, while smaller, uses up to 20% less fuel per passanger. That's a pretty significant savings, and is a breakthrough as well.

As far as space goes, take a look at the X-prize. The shuttle was not a breakthrough in space technology. It does allow us to do some things we couldn't do previously (namely bring sats back down w/o burning them up in reentry), but it's much less efficient than the older rocket boosters. The X-prize holds forth the hope of real commercial breakthroughs in space travel.

Yes, I agree, the amount of change between 1970 and now is not nearly as dramatic as the changes between 1940 and 1970. The industry is maturing. Every industry does. I guess I don't see this as an inherently sad event though.

You think _that's_ bold? Check out Project Orion...

Stuff like DUCRETE (depleted uranium concrete) is really good, 'cause it's got lots of big hefty nucleii spread out fairly evenly -- it makes them harder to miss.

The problem with magnetic and/or charged field shielding is that it only handles charged particles -- plain old neutrons get right through. On the other hand, these guys, who should know, say that the vast majority of the radiation a spaceship needs to deal with is charged particle based.

From Article 1

1. The provisions of this Agreement relating to the moon shall also apply to other celestial bodies within the solar system, other than the earth, except in so far as specific legal norms enter into force with respect to any of these celestial bodies.

3. Neither the surface nor the subsurface of the moon, nor any part thereof or natural resources in place, shall become property of any State, international intergovernmental or non-governmental organization, national organization or non-governmental entity or of any natural person.

I went through the thread with hot mod points, looking for a comment mentioning the one thing as cool as the Orion project and the /. standard story beanstalks.

Relax, people, military research is good! :-)

(-: But to actually build lots of the military stuff are usually a waste, though. :-)

The 60's saw two interesting concepts the KIWI and the NERVA projects.

Another nuclear propulsion project was the project orion.

The article just says it's technologically feasible. How boring.

In the movie The Right Stuff, and, IIRC in the book,a congressman says to an astronaut "What makes your rockets go up?" The astronaut starts to saying something about reaction masses and exhaust velocity, and the comgressman cuts him short and says, "No. What makes your rockets go up is funding."

Of course a Moon base is technologically feasible. Goodness, if we're just talking technological feasibility we should be able to be a lot more imaginative than that. (Project Orion, anyone?).

But unless someone "salts" the Moon with gold nuggets (I believe it's in Carl Sandburg's The People, Yes in which someone starts a rumor that there's gold on the Moon, and so many people start heading for the Moon that the person who started the rumor figures there must be something in it after all and joins them) I don't see how it's going to happen.

(Another nugget from The People, Yes "Another baby in Cuyahuga County, Ohio--why did she ask: 'Papa, what is the moon supposed to advertise?'" I'd give a nickel to know whether Heinlein read that before writing "The Man who Sold the Moon.")

This new explosive seems like it would be great for making better rockets of the project Orion type. Cleaner than nuclear fission but still with energy density 1000 times higher than chemical. Scalable to smaller explosions (So a smaller scale rocket could be taken up to orbit). Seems like a very finely controlled hafnium injection system could be made with X-Ray ignition.

Check out article four of this treaty.

Project Orion was the real origin of the concept of using nuclear power in space... and while the political environment changed and didn't allow it to come to being, any of you who've never heard of it and are interested in spaceflight ought to check it out. (The link is just the first link I found on Google, there's actually a great book about it here.

Yes, I do hope cheap advanced propulsion concepts get used sometime in our lifetime. Then we can start "Buck Rogering" around the solar system rather than worrying about every drop of fuel. That's when the real fun'll begin.

Most likely the propulsion system will be based on NERVA technology developed in the 50s and 60s. The vehicle has been in discussion for some time.

There have been a number of nuclear propulsion ideas over the years, i.e. ORION (using nuclear explosions) and the like, but NERVA is, imho, the best. To bad it's not practical to scale up the Ion propulsion system used on DS-1.

I've just spent 3 years with Auburn University designing an experiment for the ISS which could allow certain heavy industries to cut losses from $10 billion PER YEAR to less than $5 billion per year

Not according to this.

http://www.amazon.com/exec/obidos/ASIN/0805059857

http://www.islandone.org/Propulsion/ProjectOrion.h tml

I personally favor building big manly throbbing Orion rockets, but that's because chaos theory makes my brain hurt and because things that explode are cool.

Project Orion

When it comes to the moon, it doesn't matter how much the US government forked out to get there, it is a satellite that is covered by internationla treaty, more specfically the Moon Treaty ( see article 2, amongst others ). Others treaties of interest can be found here

BTW, although the USA was the first nation to set foot on the moon, the former USSR was the first nation to land a probe on the moon.

The "Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies (1967)" is a good example with articles like:

The exploration and use of outer space, including the moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development, and shall be the province of all mankind.

Very noble, but its hard to make a buck.

1) Magnetic shielding

2) No shielding; any damage to plants, animals, and structure could be repaired by virtue of the fact that everything is infested with "smart nanobots" - basically a artificial immune system for everything (which is also necessary to counter the threat of "terrorist nanobots" since good will outnumber evil :-).

--

Here is a link to that : here

Anyway, nuclear rockets are a great idea. A better one, you may have heard me harp on this before, is VASIMR. It is a plama rocket with a nuke power source. It will be around ten times as efficient as the nuke rockers. However, the VASIMR, unlike the nuclear rocket, it does not have enough thrust to launch from earth. It is more a slow and steady engine that runs for weeks instead of minutes. But the burnout velocity of a VASIMR can be vastly higher than a chemical rocket.
The nuclear rocket can provide cheap, efficient space launches with not too much radioactive fallout. In fact, if a nuclear rocket using helium as a propelent will produce no fallout at all. Since a nuclear rocket is about twice or three times as efficient as a chemical rocket, the amount of fuel you'd need would be slashed dramatically. A nuke rocket launch might only use 10% or less of the fuel that a conventional booster would.

It's under R&D.

It ionizes hydrogen with microwaves an then accelerates them with magnetic fields. While it doen't provide thrust like a chemical rocket, it certainly has many, many times more thrust than a ion engine. It has some oomph to it. For cheap launches, you really need somthing like the x-42 scramjet spaceplane. That would cut costs of launching by a factor of 10 with no giant lasers.

VASIMR will get a specific impulse of 30,000 seconds compared to 500 seconds for the shuttle's engines. A specific impulse is the number of seconds 1 kg. of fuel could produce 1 kg. of thrust. The specific impulse of the VASIMR is 60 times better than the shuttle. That is many times better than the ~1500 seconds you'd get with the nuclear rockets.

That would allow cheap interplanetary voyages anywhere in the solar system, using very little fuel. Using these engines, you could get to Saturn in less than a year. It would also allow slow intersteller trips of around 1% the speed of light.
Also, VASIMRs could be easily, cheaply, and quickly refueled for more missions.Interplanetary travel could become cheap. I bet each ship would cost around 5 billion dollars initialy. After that, it's cheap. After each trip, an X-42 could come and restock the ship with fuel and supplies. That would only cost around 50 million. We could send tens of thousands to colonize Mars.

BTW: On this article, it says the VASIMR gets 10,000 seconds. It can reach 30,000 with further development.
Read about the VASIMR here
--

... the Christmas tree robot in Robert Forward's "The Flight of the Dragonfly". Dr. Hans Moravec designed it for Dr. Forward, and it has since been used in several other novels by other authors.

Don't tell me Bush is thinking of bringing back Project Orion...