Telepresence — Our Best Bet For Exploring Space

Seth Shostak of the SETI Institute recently wrote an opinion piece for the NY Times discussing the limitations of our space technology. He makes the harsh point that transporting human beings to other star systems isn't a reasonable goal even on a multi-generational time frame. However, advances in robotics and data gathering could instead bring the planets and stars to us, and do it far sooner. Quoting: "Sending humans to the stars is simply not in the offing. But this is how we could survey other worlds, around other suns. We fling data-collecting, robotic craft to the stars. These proxy explorers can be very small, and consequently can be shot spaceward at tremendous speed even with the types of rockets now available. Robot probes don't require life support systems, don't get sick or claustrophobic and don't insist on round-trip tickets. ... These microbots would supply the information that, fed to computers, would allow us to explore alien planets in the same way that we navigate the virtual spaces of video games or wander through online environments like Second Life. High-tech masks and data gloves, sartorial accessories considerably more comfortable than a spacesuit, would permit you to see the landscape, touch objects and even smell the air."

Comments

Latency

[TheLink]

Uh... Aren't they forgetting the inconvenient slowness of the speed of light?

Unless they solve the FTL comms problem it takes seconds even for a short distance like Earth to Moon.

So if you are going to explore some far away place, telepresence will still require you to ship some human to the general vicinity.

Re:Latency

[LogarithmicSpiral]

You mean you still haven't figured out about the ansible?

Re:Latency

[LogarithmicSpiral]

That was an attempted reference to the Enderverse. Apologies if I sounded condescending.

Re:Latency

[Abcd1234]

Uh... Aren't they forgetting the inconvenient slowness of the speed of light?

Yes, because a member of the SETI institute never thought of that.

Honestly, Slashdotters really think *way* too highly of themselves... or way too little of the average scientist.

So if you are going to explore some far away place, telepresence will still require you to ship some human to the general vicinity.

No, because the idea isn't interactive exploration, in the sense that you remotely control the robotic probe in real time. The idea is that you collect massive amounts of data about a world, transmit it back, and then use that data to build a virtual model that you can then explore at your leisure.

Of course, such an approach will have limitations (if you decide you want to see what's under a rock, unless you knew ahead of time to turn it over, you'd have to then send instructions to a probe and then wait for the new data to come back). But its certainly an interesting idea, IMHO.

Re:Latency

[Runaway1956]

Yeah. It won't be remote controlled robots, that's for sure.

In general, we have a defeatist attitude regarding space exploration. I want to see people on the moon before I die. Even if it's only a VERY small colony with a dozen scientists and techs, with support personnel, it's a start. I want to hear plans for a Mars colony. Putting colonies in space will help to prevent the extermination of mankind due to a single cataclysmic event.

A few people have died exploring space, and we whine and cower, afraid to put people out there.

One single asteroid can kill us all. Robotics are all fine and dandy, but we need to move into space for the good of mankind.

Re:Latency

[Joren]

Uh... Aren't they forgetting the inconvenient slowness of the speed of light? Unless they solve the FTL comms problem...

Using quantum entanglement, that may not be so far off. If it turns out information can be transmitted near-instantaneously, telepresence could become a reality. Available bandwidth would only be limited by our capacity to create and address these particles and how fast we can read and write to them.

Of course, that's a big "if"...

Re:Latency

[TheLink]

It's fine for exploring nearby places like Mars. But other than that it doesn't solve the main problem.

The nearest star is 4 light years away.

If we really want to explore space we should seriously figure out plans and methods to construct space colonies that can build space colonies - and maybe one day, ones that can survive interstellar journeys.

Then it doesn't matter so much how long we take to get to various places in the solar system or even the galaxy.

Re:Latency

[Yvan256]

... followed by a big "else" and a big "end if".

Re:Latency

[Sepht]

Earth-Sun takes 8minutes 20seconds. Not 8 seconds.

Re:Latency

[mfnickster]

Not exactly that long. Earth-Moon takes 1/4 of a second.

Which speed of light are you using? The moon is about 385,000 km from Earth.

Re:Latency

[Burdell]

Wow, I can't believe you've been moderated "Informative" with completely wrong information. Light travels from the Sun to the Earth in a little over 8 minutes, not 8 seconds. You are a little closer on the delay between the Earth and the Moon, but it is about 1.25 seconds, not .25.

Also, anything interactive requires a round trip, so for practical purposes, the delay is double that (about 16.5 minutes for the Sun and 2.5 seconds for the Moon).

Re:Latency

[maxume]

The author would have a much easier time making his case if he called it computer simulation instead of telepresence (which sort of implies a near real time experience) and referred to experiencing other worlds, rather than exploring them.

I would say blame the journalist, but the author of the Op-ed works at the Seti Institute, so he probably knew exactly what he was doing.

Re:Latency

[durrr]

If we really want to explore space we need to start with developing a propulsion system that would get the bloody colony ship to the target destination in say, less time than it takes for the colonists to evolve until they're about as related to us as bacteria.

Our probe farthest from earth(voyager 1) is a puny 14-15 lightours away from the sun. And it's been at it for 32 years. If my mathemagics are right that means those puny 4 lightyears will take roughly 75000 years to travel.

That's definitely not an acceptable timespan. Relativistic spaceflight is a must if we're too see more than our backyard.

Re:Latency

[timeOday]

Robotic exploration already accounts for 100% of our success in visiting other planets. We have a lot to learn before attempting colonization and natural resource exploitation, and space exploration isn't for the personal gratification of astronauts... therefore, whether we send people or robots, the only real goal is to send home information.

Re:Latency

[maxume]

I don't really agree. I'm not an astronomer or anything, but I would think that most of the interesting science that is done using interstellar probes will end up being done via data analysis, not utilizing systems that simulate environmental engagement (if that doesn't describe the essence of telepresence, then the word doesn't mean anything anyway).

So interstellar probes probably will be used to explore the universe, but describing something where input and feedback takes years as telepresence doesn't add any clarity to your message, and it maybe makes telepresence less useful as a word.

Re:Latency

[Idiomatick]

Agreed. But what most scientists and nerd forget is what another poster said. If 95% of the population will pay MUCH more for football than science you are fucked. Telepresence might get people interested again. The main thing holding back NASA at the moment isn't their shitty new shuttles. It is PR, they don't have a groundswell of support. If there was a movement like the one to get a man on the moon we would be having massive innovation coming from every orifice. But most of the world doesn't care. So we are stifled.

Re:Latency

[earlymon]

Honestly, Slashdotters really think *way* too highly of themselves... or way too little of the average scientist.

I believe the question was about whether this plan takes into account that there's a speed limit. Realistically, the best idea within our present technological imagination is either solar wind sails or ion drive. With either of those, the further you go, the faster you'll go. But at the halfway point of either of those technologies so far, you reverse the craft (drive) because it takes as long to decelerate that accelerate. Now, doing an rough order of magnitude calculation where you achieve half of the speed of light, it will take you more than 4 years to get to the halfway point of our nearest star, more than 8 years to get there, more than 12 years to get your first signals back. So - rough order of magnitude - take the distance to target in light years, multiply by 3, to get time to receipt of first signal - minimum. (Yes, the approach falls apart the further you go out - I beg the reader's patience - note well that a target 60 light years away will take (way) well over 120 years, anyway.)

So - I do not see how your response to the question in any whatsoever responds to the question.

I don't know who these Slashdotters are that too highly of themselves of which you speak. I have worked space systems - to iterate in clear text: platforms I've performed significant (at the very in least, in time and level of effort) work on are in deep space flight as we speak. I have worked under the auspices of the US DoD, DOE and NASA.

Some people might think that I think pretty highly of myself. In fact, it's a common common occurrence in my real life to meet that prejudice. But I do not think too highly of myself because at the aforementioned agencies, I've met a lot of people who are really smart, and I wouldn't dare to lump myself in with them.

In other words - the validity of a question in the world of science has absolutely nothing to do with who thinks what of themselves and who has what credentials. In the world of science and engineering, good questions and good points stand on their own merits.

That said - it is a VERY good question as to whether or not extreme distance has been taken into account. As far as I recall, the neighborhood doesn't get interesting until you get out some 20 light years, at least. The parent's question is VERY good because it raises at least one really interesting engineering question - who here believes that the envisioned ground-based tech will survive for 50 or more years? Probably no one. Who here believes that this will just all work out with equivalent or presumed-superior future technologies? Who want to raise their hand without a brief overview of the many case histories where that was NOT the case?

Here's another good question: what does it mean that these proxy explorers can be very small? So far as I recall, the only tech to get data back will be on some kind of EM wave. So far as I know, the viable viable EM tech - due to maturity, reliability, power consumption and xceiver size - is radio. I repeat the question - what are the assumptions of equipment size, weight and power consumption when we say we can do this - transmit from, say, 20 light years away? In other words, what is this "small" of which SETI speaks? (Another reference to the parent's unaddressed concern about comm problems, but from a different perspective.)

Permit me to reign back from interstellar to interplanetary - and continue my criticism of the quotes attributed to Dr. Shostak (kindly note my important choice of those words) - at what point would I want to experience the smells of the deadly airs predominant in our solar system? Ridiculous!

Dr. Shostak is well published and credentialed. However - the summary and article suggests that either the NYT is lame or Dr. Shostak is.

Therefore, your criticisms of TheLink are neither insightful nor well-founded. You did not addres

Re:Latency

[buchner.johannes]

The furthest traveled object (Voyager 1) has gone for over 30 years with very high speed and has not even left the planetary system yet (it is around the distance of Eris, ~110AU), not to mention Heliopause [1,2].

Here is your flight map though: http://en.wikipedia.org/wiki/File:Solarmap.png (note: logarithmic)

Can we ever overtake this? Good luck getting a object faster than Voyager 1.

[1] http://en.wikipedia.org/wiki/File:Voyager_1_entering_heliosheath_region.jpg
[2] http://heavens-above.com/solar-escape.asp?/

Re:Latency

[wpiman]

Will these robots also include appendages for being able to make love to an alien life form the way James T. Kirk does?

Re:Latency

[Teancum]

Robotic exploration already accounts for 100% of our success in visiting other planets.

Hardly. 100%? A dozen people made it to the Moon (arguably a dwarf planet... and called such by the astronauts who went there) and performed more and better science than all other exploration of the Moon by all previous and subsequent robotic explorations of that body. An additional dozen people... mostly aircraft test pilots... got to at least see the Moon close up.

There are a whole lot of reasons to send actual people to these places... and information that comes from somebody who is there sensing the environment with their own nervous system and capable of seeing, feeling, and otherwise sensing things that simply aren't or can't be identified remotely.

Futhermore, simply being in a different environment and having to face new challenges that other people haven't coped with before creates new thought processes (new neural pathways) and forces you to think in ways that creates additional knowledge.... and often those new ways of thinking can be applied to existing problems in a new context. Getting other people to other planets... and yes, even other star systems (eventually... as technology and space technologies permit) can do nothing but help improve nearly everything that we hold dear to ourselves as human.

BTW, I sure hope that at least some exploration of space is for personal gratification. Hell, I know it is.... that is why they put up with the bureaucratic bullshit, red tape, government committee meetings, press conferences, doctors probing in places you never knew existed in the first place, and all of the other headaches to spaceflight.

One shuttle astronaut that I read about had the experience of being able to face away from the Earth, the Shuttle, and all of the equipment he had for about 10 minutes during an EVA while the rest of the crew was putting away some equipment and dealing with some other tasks. The view of the heavens he was able to experience for that brief moment of time with nothing between him and starlight but a think piece of Lexan (and an inch or so of air) was a breathtaking experience this astronaut claimed made the whole experience of becoming an astronaut worth the effort. Other astronauts have said the same thing during their "break" times where a common privilege is to simply gaze at the Earth during one complete orbit. We need more people to enjoy these simple pleasures that come from spaceflight.... and I hope that poets, writers, and artists of all other types can experience something of that nature eventually and be able to give the rest of us a glimpse of what that sort of experience is like.

You could even argue that the modern environmental movement; global warming concerns, oceanic pollution, nuclear winter, ozone depletion, and much more; was initiated because a few astronauts had the privilege of being able to see the Earth rise up over the horizon while orbiting the Moon. NASA gave them instructions to take pictures... as many as they could click with their cameras (including cameras mounted remotely on their vehicle) of the surface of the Moon. But when these guys saw the Earth come up... they realized on the spot with no other instructions that they had to get some photos of the Earth as well. Even today, these are some of the most heavily requested photos from NASA and are arguably the most duplicated images in the history of mankind. These images would not have been made if it weren't for a person in orbit around the Moon to make them.... the bureaucrats planning the mission on the ground never thought of making them.

Don't even get me started on how limited the robotic missions have really been... even though what has been accomplished with the robotic missions has been incredible. There is a role for robotic exploration, but there is a role for a physical presence of human being in space as well.... and not just in low-earth orbit.

Re:Latency

[Runaway1956]

A large enough asteroid impact could cause the earth to look like this: http://en.wikipedia.org/wiki/Asteroid_belt

I doubt that mankind would survive such an impact today.

The purpose of a lunar colony, in and of itself, is NOT to ensure the survival of such an impact. In all likelihood, the same impact would make the moon uninhabitable, sooner or later. (without the earth, the moon will probably not maintain a stable orbit around the sun, not to mention the debris raining down on the moon)

Rather, the lunar colony provides experience and knowledge applicable to building more colonies further out in the solar system, which will help to ensure mankind's survival.

Ulimately, the goal is to put man onto planets outside the solar system. Today, THAT is a near impossibility. But, if we are afraid to tackle the difficult project of colonizing the moon, we will certainly never achieve the near impossible.

Re:Latency

[gyrogeerloose]

I've got just word for you, son: teledildonics.

Re:Latency

[tukang]

I always find it easier to remember numbers like 384, 192 etc. which are sums of powers of two.

Good news. Every number is a sum of powers of two.

We need a warp drive...

[drolli]

really.

Re:We need a warp drive...

[cjfs]

Yes, but until then, lets just try another star trek approach.

'Human'

[FlyingBishop]

The real first step in exploring the stars will be re-evaluating what it means to be human. This article assumes that our descendants will be flesh-and-blood, with all of the weaknesses that that entails. But why should we bind our offspring to the ancient, easily-corrupted, and not so easily amended DNA that we ourselves use, when we could give them minds of silicon and arms of steel which fold up in an instant to sleep for the journey from star to star? Or better still, why not send a simple automaton, and transmit its brain at the speed of light? Human is as human does, I suppose, and the human era will quickly draw to a close if we decide that human must mean flesh and blood.

Re:'Human'

[Anonymous Coward]

I find your idea fascinating, may I subscribe to your newsletter?

Re:'Human'

[DavidChristopher]

Yes! We could start out with robotic, sentient bipedal metal human analogs.

But why limit them to exploration? They could also work in our factories, mines, and ... oh... even better - wage our wars. We could call them "Centurions", in honour of our ancient roman brothers. I suppose we could also give them one red back-and-forth scanning eye, too.

Why does this all sound familiar suddenly?

Re:'Human'

[catdriver]

Or, if you believe we're all about to have our personalities uploaded to the great singularity in the sky like Ray Kurzweil, you could have an instance of you uploaded to a tiny computer-starship, and live in a virtual environment for the entire journey.

For an interesting and entertaining take on this concept (and other singularity-related ideas) check out the novel Accelerando by Charles Stross.

It's a great book by a fellow Slashdot user, and you can download it free!

(Then go buy some of his other fine works)

Human exploration IS worthwhile IF...

[kulakovich]

...you are interested in something other than sports, iPods, and Coach bags.

If your society can't be bothered, you're damned to spend more willingly on the NFL each year than you begrudge the entire space program.

Enjoy your cell phone.

kulakovich

Re:Human exploration IS worthwhile IF...

[canadian_right]

The long term goal of all space exploration should be a permenant human presence on another planet, Mars most likely. All the science is great, but I want the human race to survive if the Earth takes a big hit.

Re:Human exploration IS worthwhile IF...

[Nyeerrmm]

Simple. If it takes longer than ~8 years to get benefits from an expensive project, it becomes much harder to get funding, at least in the US. Also, if development takes more than 8 years on something high-profile and expensive, there's a good chance you lose funding at the start of a new administration. Doing this would take longer to even get going. I'd venture a guess that in other countries there are similar election-cycle limited periods for project funding. In other words, we'd need a completely new structure for the way we conduct this kind of business, something thats better able to (forgive the phrase) stay the course as well as better able to see and understand very long term benefits.

Also, we have no data on maintaining systems that would last that long autonomously, so while you could theoretically make something capable of getting there and braking into orbit, its unlikely you could build it to have a reasonable expectation of success. That of course is a technical problem, so solutions are out there; the political problems are the ones that'll kill you.

Round trick tickets?

[palegray.net]

Put me on the first ship that isn't coming back. I think the prospect of living out your life as part of a colony on its way to who-knows-where in the cosmos is a pretty neat idea.

Re:Round trick tickets?

[gmuslera]

If that ships enables you to live (even in suspended life form) till you reach almost anywhere outside the solar system, probably you will be the only earth survivor by the time you reach there, at least with most current technologies. Sending seeds of human civilizations out there could well count as a backup system, specially counting the amount of times things happened here that could wipe the entire race or at the very least the current civilization.

Sending "watchers" first, robots, AIs, telepresence, etc, could avoid some of the risks, but will we have enough time?

Re:Round trick tickets?

[siriuskase]

You or any other individual doesn't need to live that long. All you need is to create a vehicle that can be a comfortable home to a group of people who can live together and reproduce without killing each other off. They can work at maintaining the vehicle, producting food, and use simulations for entertainment and exercise. If the group doesn't contain pairs that can breed safely, even that can be acomplished with in vitro fertilization, using simulations of better than the real thing to make it more fun.

This would probably require a lot more psychological and physical testing than required to live on our current spaceship, but for those lucky enough to pass the tests, it could be an extremely satisfying lifestyle. Sign me up.

virtual astronauts ..

[viralMeme]

"Uh... Aren't they forgetting the inconvenient slowness of the speed of light?"

Send a craft with a virtual reality simulation of a crew running on board. On the journey have the VR simulation recreate contemporary earth culture. The VR program fabricates various crises for the 'crew' so as to keep them occupied and to distract them from the knowledge that they are in a simulation.

When the craft arrives at the destination connect the VR simulation to robots through short-range-high-bandwidth radio connections. Have the VR simulation be updated by the robots interactions with the real world. Then beam the simulation back to Earth and run it locally with humans plugged in to it.

'Have you ever had a dream, Neo, that you were so sure was real? What if you were unable to wake from that dream? How would you know the difference between the dream world and the real world?'

Comment removed

[account_deleted]

Comment removed based on user account deletion

Sooner or later

[Jane Q. Public]

we are going to have to put some human beings somewhere else besides this one ball of rock.

Saying that even multi-generational ships are not "a reasonable goal" begs the question (and is debatable... after all, this is an "opinion piece").

Reasonable or not, eventually it will be done. I have nothing against robotic explorers, but only as precursors to something better.

Idiots

[SuperKendall]

Not the proposal exactly (well with latency actually yes), but...

Robot probes don't require life support systems, don't get sick or claustrophobic and don't insist on round-trip tickets.

They also can't use intuition and years of training and curiosity combined to go, "hey what's that" as they glance over to the side at something a rover would have just rolled past.

We could learn more in a day of manned exploration of Mars for example than we have with the entire exploration effort to date.

Humans are too flexible not to send out for exploration, and I hate to say it but far cheaper to build (though again you have the issue of latency).

I also refuse to believe we'll never be able to freeze and re-animate a living person hundreds of years later, though that will take a good long while to get right.

Erm

[Anonymous Coward]

The humans on earth can only "experience" what has been observed by the remote observer. If the remote observer passes by a planet and scans it at a great distance, the human explorer will be placed into a distorted bizarro world with poor resolution, and lifting a rock cannot be done because the remote explorer could not check to see what was under the rock.

Alternatively, you can have an AI "fill in the gaps" and assume what was under the rock. In that case you might as well play a video game.

Re:Erm

[Shamenaught]

Please, when did either I or timeOday state that "everything we know about the Solar System besides the Earth and the Moon comes from robotic missions"? Allow me to quote the statement I defended:

Robotic exploration already accounts for 100% of our success in visiting other planets.

That's visiting other planets, no more no less.

Your choice to bring telescopes into this is an interesting one, however. I'd expect that every telescope of scientific use for the last 25 years has been essentially controlled by a machine (I know as my father was a programmer for instruments on telescopes as long ago as 27 years ago), making it a large stationary robot. When does it stop becomming robot-power and start becomming man-power?

I'm not saying that it's impossible to get to the moon, merely that it's much more expensive. Given that the space race was basically a big political dick-swinging contest, unless some power attempts to swing its dick to mars and another government thinks its dick should get there first then I don't think there's going to be a manned trip to mars any time soon. Science can fund far more unmanned trips to mars than it can fund manned ones, and unless you equip a manned mission to perform every single experiment you ever could desire to do then it's probably cheaper to send multiple smaller missions with specific goals.

It all comes down to cost versus benefit. You might be able to get there in one week, but is that ever gonna be cheaper than seinding a robot there in 9 months? The benefit of sending a human to mars would be relatively small, as basically they'd just be overseeing robotic sensors and it'd cost them a lot to get there anyway. When they want more mineral samples, they're more likely to send a robot with the ability to return samples than a manned team with shovels and bags. the mars landings happened when robotic technology was basically unheard of. If they wanted samples from the moon nowadays, they'd just send a robotic probe.

I'll berhaps retract my 'hopeless romanticism' assertion, but only the hopeless part. I agree that the technology exists for man to reach mars. It's just that there's no reason to send man to mars other than the romantic assertion that something must be experienced first-hand to be understood. Scientists have been making reliable observations through machines for many years now, maybe even before people reached the moon. I see no reason for them to stop now, especially with advanced telepresence technology around these days.

Misleading article

[janoc]

Unfortunately, the author doesn't have a clue what he is talking about. He seems to be talking about sending a probe, collecting information and then building an offline environment to explore, not a real-time remotely-controlled robot. That is actually a potentially feasible task. It has only one major flaw - it is not telepresence.

For telepresence ("feeling being present in a remote place") you need to be able to have real-time response to your actions, not only watching what essentially amounts to a souped up QuicktimeVR. The interactivity is not optional and that doesn't come from VR goggles and gloves but from the realtime feedback look. Which is obviously missing, unless your want to do something like use alien planet data for playing CounterStrike or be happy with 6.47*10^11 ms ping ... (that is the roundtrip time to Epsilon Eridani mentioned in the article - 10.5 light years away).

It is a pity that people talk about virtual reality and related fields without even understanding the basics - but that is the consequence of media hype surrounding this field, together with people calling non-immersive, often even non-interactive applications "virtual reality". Computer games, SecondLife, QuicktimeVR are not VR, period - you cannot really achieve meaningful feeling of presence there. Of course, it sounds and sells better if you stick a gee-whizz sticker on the box ...

Don't let second lifers at the data

[Anonymous Coward]

My God ... It's full of flying phalluses

Re:Ignores time dilation

[Runaway1956]

I'm ready. Hell, I'm 52 (errrr, uhhhhm, 53 tomorrow) and I'm ready to go. What's wrong with the younger generation? For that matter, what's wrong with MY GENERATION?!?!?!

Build that big assed Roman Candle, give me some room and some food, and light that bastard off!!

Re:Just ask one of the ET's ;)

[Yvan256]

On second thought, let's not go to Camelot. It is a silly place.

IF?!?

[symbolset]

I want the human race to survive if the Earth takes a big hit.

Did you mean to write "when" instead of "if" here?

When the robots land, what they'll find is...

[Alaska Jack]

More advanced robots, that we developed (along with much faster propulsion systems) in the decades since the originals were launched.

Hat tip: Carl Sagan, I think. Or maybe Azimov.

    - Alaska Jack

What risk?

[denzacar]

Sending "watchers" first, robots, AIs, telepresence, etc, could avoid some of the risks, but will we have enough time?

If there is one resource we have a shitload more than we need or know how to handle its - people. Should we really care for their safety back on Earth?
1.8 people die every second. 106 every minute. Do we hold a minute of silence for those 106 every other minute? People are highly expendable.

Safety is not a problem. If you send colony ships time is also not a problem. Even technology is not really a problem - even now.

Problem is in the liftoff price per kilogram.
Once we get it down to around the price of an intercontinental flight today - colonial-sized ships will start costing something like cruise ships today.

When we get it down to what it costs in gas to drive 100 km today - colony ships will be cheap as jumbo-jets are now.
Only then - we will not be interested in going outside the solar system cause there is enough to keep us busy and well fed here for couple of centuries.
Well... most of the people that is.
Some of us will be busy digging habitat holes in an asteroid or two, strapping some engines to it and pointing it towards the nearest exoplanet.

Re:Ignores time dilation

[CrimsonAvenger]

(A) What is the maximum acceleration that the human body can withstand?

Who cares, we're not going to be accelerating at much more than 1g in any case, and probably a great deal less.

(B) At that acceleration, how long does it take to reach a significant fraction of c?

0.95c is about turnover speed for a 1g trip to Alpha Centauri. It'll take about 21 months to reach that speed, and another 21 months to stop. So Alpha Centauri at 1g is about 3.5 years away.

Everything else is farther, of course. But not a lot farther, since you've done the slow part already. Twenty years can get you anywhere in the galaxy at one g.

Re:Ignores time dilation

[colinrichardday]

Humans can sustain an acceleration of 10m/s^2 (a little more than 1g). One day (86,400s) would lead to a speed of 864,00m/s. To reach a speed of .9c (270,000,000m/s) would require about a year. It would require the same amount of time to decelerate. The problem is that even a speed of .9c does not give you much time dilation. We have gamma=1/sqrt(1-.9^2), which is 1/sqrt(1-.81) or 1/sqrt(.19), which is 1/.44, or about 2.3. Hence, one would age 44 years on a 100-light-year voyage.

Re:Ignores time dilation

[rcw-home]

A: For extremely short durations, a small sample size of humans have survived 150G. However, the green 50G shock stickers are commonly used on dummies to equate to major injury. 9G is about the most anyone can take without blacking out, even lying down. I suspect for long-term endurance you may be limited to 2 or 3G and even that would require extreme physical training.

B: Google calculator can easily answer this one: http://www.google.com/search?q=c%2F(9.8m%2Fs^2*3). Replace the 3 with whatever acceleration rate in G's you want.

The hard part, of course, is finding a powerplant that could actually do that.

The problem with robotic exploration is.....

[kenwd0elq]

The problem with exploring robots is that they can never discover anything that they weren't DESIGNED to discover. All you can do is to confirm or deny your original biases; they can't discover anything NEW. No serendipitous discoveries.

Sort of like where we are right now with explorations of Mars; the first Mars Rover searched for life and didn't find any. Now the Mars polar probe has discovered what may be anomalous methane readings - but we can't remotely reconfigure the probe to figure out what we're actually discovering. A new generation of Mars probes will be needed with better sensors to either prove or disprove the notion of Martian life.

Which is not to say that a generation or three of robotic probes wouldn't be a good and valuable thing to do before shipping valuable people to other star systems. But robotic and "telepresence" sensors make very little sense except as the first step that will eventually lead to human exploration and colonization.

Silly argument

[horza]

Here's an idea... we can do what we've always done which is BOTH. We were putting men on the moon and planning men on mars whilst sending 'telepresence' probes to Saturn and Jupiter. We can put men on mars and plan to orbit further out whilst out 'telepresence' maps out Pluto and beyond. And we continue to push outwards with the probes paving the way with their data and humans following up and doing what we do best.

Phillip.

Re:Ignores time dilation

[d474]

Twenty years can get you anywhere in the galaxy at one g.

Try 74,000 years. Our Milky Way galaxy is approx. 100,000 light-years in diameter. We are about 26,000 light-years from the center. Even at the speed of light, it would still take us 74,000 years to reach the far side of the Milky Way galaxy.

Twenty years would only get us, well, about 20 light years away from our Solar System which is drop in the bucket compared to the size of our galaxy.

Erm

[Shamenaught]

The moon isn't a planet, it's a moon.