What next for the 100 Year Starship Study? NASA and the Defense Advanced Research Projects Agency will make the call, as Tau Zero founder Marc Millis told Alan Boyle in his recent interview. To talk to Boyle, Millis donned virtual garb and appeared in Second Life in robotic form, but the interview is now available as a podcast on BlogTalkRadio and iTunes. I’ll send you there for the discussion in full, but do note that Boyle talked to Millis about starflight before the show and has made an edited transcript of that conversation available on Cosmic Log. The quotes I use below are from the earlier talk, but do pick up the podcast and listen to the whole thing.
Where DARPA goes next is to make a decision about awarding the funds remaining from the $1 million originally put into the project. About $500,000 is available, and Centauri Dreams speculates that DARPA will be more than happy to allocate the funds and be done with them, thus removing ‘starship funding’ from a budget always sensitive to congressional oversight. The plan all along has been to put these funds forward as seed money to the organization that can carry forth the 100 Year Starship idea. In other words, DARPA is hoping to boost interstellar flight by supporting a long-term effort that will find financing and develop technology that one day leads to the stars.
Millis has previously calculated that an actual starship is as much as two centuries away considering historical patterns of energy production and use, but projections like these are always approximations. The important point is that work on a starship has to be approached rationally. Given that we have numerous propulsion options, all of them with huge engineering issues, we have to investigate which of them might evolve to the point where a deep space mission is possible. And we have to take into account huge peripheral matters like equipment reliability over long time-frames, communications at interstellar distances and the matter of human longevity.
Research is invariably incremental, and considering the early state of our knowledge, it will proceed by identifying the key issues and laying a foundation now to chip away at them:
The important issue to figure out today is to make sure we have a sane comparison of the real challenges and the real state of the art, so we’re proceeding wisely here. Then, from that, ask, “OK, if that’s where we are, what can we start tomorrow to chip away at those issues?” We can’t build the starship tomorrow, but we can identify the correct questions to ask, and begin seeking answers to those questions. When it looks more promising, and the advancements are there, fine.
Those advancements may be a long time coming, and there is an inherent danger in impatience. An organization built to last a century or more crosses generations and requires a sustained vision (I’ll be talking about exactly that in an upcoming dialogue with Michael Michaud, to be published here within the next two weeks or so). A public saturated with immediate gratification will not support such projects, but a public educated in the problems involved and the magnitude of their solutions may begin to see things in a long-term context. Amortize interstellar research over two centuries and the costs are more manageable and can grow with the economy. Along the way, as DARPA keeps emphasizing, we should be looking for tangible, near-term spinoffs.
Lately I’ve been reading the new edition of Robert Zubrin’s The Case for Mars, which energetically describes the thinking behind ‘Mars Direct,’ a way to reach Mars with existing technology and with far less expense than many government projections have indicated. But we all know that even Mars, that close and astrobiologically tantalizing world, is still out of reach for the present because of political and economic factors. An interstellar mission is a step so far beyond these tentative steps in our Solar System as to dwarf them entirely. Why, then, look ahead to traveling between the stars when we’re still so early in the game in our own system?
The ultimate, highest-priority benefit of star flight is the survival of the human species beyond the fate of our own solar system and our home planet. In the meantime, the progress we make to try to turn all this stuff into a reality will result in profound improvements in energy conversion, transportation, self-supporting life support — things that would be very useful for life on Earth. And then there’s the social aspect. This effort can give us hope for a better future, expand our opportunities — and hopefully give people a frontier to conquer, rather than being left with no option other than to conquer each other.
Can human cultures pull together to manage major questions of species growth and survival? It’s only one of the questions interstellar flight raises that Boyle and Millis tackle in the longer interview. What we can say is that building a space-based infrastructure is an obvious precursor to an interstellar probe, and getting economically to low-Earth orbit is an obvious precursor to moving outward into the Solar System. Each of these challenges has its advocates and interstellar flight will depend on a satisfactory resolution of all of them. But the challenges of starflight are so immense that chipping away at them now helps to lay a groundwork that will become the roadmap to follow when we do achieve the technologies needed to reach a star.
Paul Gilster said in this article:
“Where DARPA goes next is to make a decision about awarding the funds remaining from the $1 million originally put into the project. About $500,000 is available, and Centauri Dreams speculates that DARPA will be more than happy to allocate the funds and be done with them, thus removing ‘starship funding’ from a budget always sensitive to congressional oversight.”
That is the same kind of thinking in the first half of the Twentieth Century by the US military regarding first the airplane and then rockets. Those then in charge just could not see the use for such inventions – until World Wars One and Two fixed that mindset in a hurry.
Not that I want our starships turned into swords unless absolutely necessary, but since the possibilities for such machines are no longer science fiction and this is now the 21st Century, a little out-of-the-box thinking by our so-called leaders would be a refreshing change. More than that, it may soon come down to either expanding our thinking and horizons or head towards extinction the way society is going these days.
Paul Gilster then said, in regards to Zubrin’s plans for sending humans to Mars:
“An interstellar mission is a step so far beyond these tentative steps in our Solar System as to dwarf them entirely. Why, then, look ahead to traveling between the stars when we’re still so early in the game in our own system?”
My first reaction is, why not? We could have sent humans to the Red Planet in the 1980s if we had followed the original post-Apollo plans. Orion could have gotten us around the Sol system and prepared us for Alpha Centauri by the end of the last century had we also stuck with its promising start in the early 1960s.
If we keep thinking something is too much or too far off for us now – not to mention that dreaded, slam-on-the-brakes, off-base thinking of needing to solve problems on Earth first (yeah, good luck with that) – then it will remain so until it becomes too late for us to do anything about it.
Time is short on this planet for current humanity. Either we expand outward or we remain here and end up with eventual stagnation at best. Even if we all lived in some kind of social and environmental harmony, an errant space rock or maybe someone with galactic ambitions could take out such a culture in short order, all because it forgot that it is PART of the wider galaxy and universe, not some separate, special domain.
We have been lucky so far, but now it is time to wake up and get moving.
Nicely put Larry. Problems on Earth might be solved by the solutions we develop for Out There too. A fresh environment to stimulate innovation.
ljk, I have been saying the SAME thing for so long! People think that this planet is stuck in some kind of bubble, and that the things that happen in space have NO effect on what happens here on Earth.
WRONG!
It’s only a matter of time before some gamma ray burst or other terrible event wipes us off the face of the planet. It’s not even a matter of if, but when. Not to mention the fact that our sun only has a finite lifetime. So the sooner we can get off this planet and keep maturing the technology to do so, the better!
Also, imagine if the government had the same vision for interstellar travel that it did for getting humans on the moon. Imagine the increase in STEM students, innovations and general public knowledge about space! Sometimes (maybe even more than sometimes), people need a fire lit under their behinds to get things really moving!
Well, yes — repeat, no. Everyone agrees that the Apollo program was a vanity/military might mission. The proposed mission to Mars bumped up against the fact that it was, indeed, primarily a science venture. In terms of payoff in both knowledge (including the possibility of a second life sample, self-sustaining closed systems and ability of humans to withstand interstellar missions) and technology, Mars is so obviously the best goal that it’s hard to listen to the mutterings about Moon and asteroid missions.
Such missions may increase general knowledge and enthusiasm about space — as long as it’s not the literal circling in the same LEO spot of the ISS or the terminally boring “return to the Moon”, and if the First World can get its act together economically and socially. As in, not electing a happy-to-know-nothing science foe to the US Presidency. As in, not pursuing policies that destroy the middle class. Etc, etc. Otherwise, the First World will rapidly devolve into the Third, and the window will close.
I say we need a Spacefaring soceity before U head into deep Space:
colonized Moon, Mars, asteroids, Space colonies, then Deep Space.
See Star Trek role model.
“It’s only a matter of time before some gamma ray burst or other terrible event wipes us off the face of the planet. It’s not even a matter of if, but when. Not to mention the fact that our sun only has a finite lifetime.”
I just cannot buy the argument that we have to worry now about an event , such as our sun dying, that will bot happen for some five billion years. And any decent gamma ray burst strong enough to wipe out our system will likely also wipe out the nearest systems we could get to so there is not much we can do about that possibility for a long long long time.
A much more pressing possibility is a biological disaster which we can alleviate by a colonization program of our own system.
I strongly encourage anyone who has read or is considering reading “The Case for Mars” to likewise pick up and read “Entering Space”, also by Zubrin. His case for Mars is summarized in a chapter of the latter book, which provides a broader vision for general expansion into the solar system and is an equally compelling read.
I admire the intentions of those involved in the 100 year starship study and I am confident that some good ideas will emerge out of the research over a period of time, but I lament that even if the study was given 10 or 100 times the budget it was given it will very likely not result in the eventual construction of a starship. The actual construction of a starship will ultimately be, in all likelihood, decided upon by socioeconomic and/or ecological factors.
It is very easy to jump to the conclusion that what is holding us back is technology. Not so fast. A lack of technology is not what is holding us back. The first order reason is that our species is not making space exploration/colonization a priority. If it was made a priority instead of largely abandoned during the 1970s, then I agree with ljk’s assessment: we would very likely have long since been hearing about the goings-on of our lunar and Martian colonies on the nightly news instead of hearing TV news anchors report on the results of a simulated 500 day Mars mission. Like the stagnant situation with respect to renewable energy, sustainability, and social justice, the technology is there or at least close at hand, the will to use it for the betterment of life is not. Nothing less than a profound transformation of consciousness is what is necessary to avoid global disaster AND make the effort to become a spacefaring race. Extinction is the alternative.
Indeed, Stephen. We’ll need more space infrastructure in the solar system before we can launch a starship.
I’ve often emphasized that getting to orbit is a major issue. Chemical rocket launches are costly and difficult. What we need is a launch loop or similar system that can truly open the final frontier. Once it’s cost-effective to go to orbit, the forces of exploration, economics, social flight, and wanderlust will push us much further. But first we must open the floodgates.
Istvan: precisely the two Zubrin books I have, very inspriring indeed.
Larry for president (and Athena as his chief science advisor).
Back in the seventies Gerald O’Neil thought out a detailed sceme to start up a space infrastrucure on a big scale with relatively small investments . One of the original ideas was the use of a solar powered masslauncher on the moon to launch raw materials , or partially processed materials to an orbital factory or space collony , which would then be mostly independent of expensive launches from earth . This is an idea which might become possible on a smaller scale relatively cheaply , if a few buildingblocks of technology can be prepared . What could the minimum requirements for a masslauncer on the moon be ? Perhabs it could be much smaller than O’Neil originally imaginned i it to be . One way to get started might be to land an all-purpose teleoperated robot on the moon which would be capable of prospecting for places to start miningoperations . The same robotsystem or an upgrade of it ,would be used to asemle and operate the first smallscale mining and production of materials like glass , allumonium and probably several other rawmaterials , which would be used to produce a big part of the masslauncher and or whatever infrastructurwe would be desirable on the moon . As technology advances it will eventually be possible to make all theese equipments small enuogh to be launced on a single rocket . Therefore it should be a high prioryty to get a rover type robot launched to the moon , if this ,even as a sideeffect , can be used to make some of the first prospecting and to get some practical experience of the moon as an environment for long lasting industrial equipment . It WOULD have to be very longlasting equipmnet , because a 20 kg alluminium factory would need several years to produce someting usable .
A mass launcher can be as simple as an electric motor and a long string, like a giant lawn trimmer. You keep it rotating and attach payloads at the hub so they can slide out and be flung out at 1.4 times the tip speed. This would be much cheaper, lighter and less complicated than the electromagnetic canons that most people envision for a catapult. Highly efficient and high throughput, too.
@Tiffany Frierson
Quite true- most people don’t seem to realize that the Earth is a tiny planet in a vast universe, and that events that happen in space affect life down here. We do not live in some special, separate domain- we are in space right now and affected by events that happen in space all around us.
Our planet-bound civilization does face eventual extinction at the hands of asteroid impacts, gamma ray bursts, or the inevitable day when our sun expands into a red giant. An old poem discussed the inevitable end of our entire civilization and everything we knew and were- the bones of long-dead humans crumbling to dust under the glare of a bloated red sun and long deserted building scorched to ash on a dying Earth, etc. Even if future humans lived in ecological balance and societal peace, no longer having to fear war or disease, someday they would be wiped out by the death of our world.
This grim, inevitable future is dashed away by the rocket ship. With a rocket ship, we can travel to other planets and escape cosmic extinction. This makes a very good argument for space travel. If we don’t start developing these technologies right now, by the time the majority of humanity realizes we might have to, it will be too late.
But we should not dwell too much on cosmic doomsdays!! Right now, there are many crisis that we will soon be facing or already are that space technologies can help alleviate. There is a slew of problems waiting to be solved. Closed life support systems will lead to new methods of supplying food and clean water- we could even build cities that supply all the power, food, and water the population needs. New energy production technologies will replace dirty fossil fuels. New aerospace propulsion technologies will lead to a new age of air and space travel. The spin-offs from space technologies already proliferate modern-day society. Satellites provide TV signals, improved materials developed for aerospace uses are applied to everyday uses, and even the non-stick coatings on frying pans were originally developed for nuclear rocket engines.
I believe the greatest incentive for space travel is providing us with a truly exciting future, one where the human species not only survives but thrives amongst the stars- a future where humans explore strange, exotic locales in the name of science and free enterprise. Rather than presenting children with depressing, bleak futures where collapsing nations face dwindling resources, climate change, and overpopulation, we can give them an exciting future to work towards. The mere mention of space travel, exoplanets, and black holes is enough to get a curious child intrigued.
With all the problems facing modern day society, any future society with space colonies will be better than one where we remain planet-bound, stagnating and quarreling amongst ourselves. I think this is a point we should make- developing space technologies will lead to massive spin-offs that will help solve the problems human civilization faces “back here on Earth”. Like it or not, human society is heading towards a threshold where we will either become a functioning Type-1 civilization or regress into a primitive state, possibly being wiped out by disease or war. I’d far prefer the former option.
And, yes, in the end only a civilization that develops interstellar travel will be able to survive cosmic disasters like dying stars or the like. It is time that people realized that we live in space, not in some special domain, and what happens up there affects us down here- which is what science fiction stories told people all along.
My apologies for playing a game of Whack-a-Mole, but…
> Millis has previously calculated that an actual starship is as much as two centuries away considering historical patterns of energy production and use
But it could make several orders of magnitude difference comparing a huge fusion ship versus the smallest possible probe launched using beamed propulsion.
> will result in profound improvements in energy conversion, transportation, self-supporting life support — things that would be very useful for life on Earth.
When plans are justified by their spin-offs, it would seem that the mission itself is not justifiable. Yet it is hard to understate the value of the survival of humanity. But if humanity isn’t threatened then spending where there is no threat isn’t justifiable. Yet humanity is under real threat. Not likely from gamma rays, asteroids, environmental changes, the sun’s death – these are either improbable or have technologic solutions. Rather biotech threat, yes, but also nanotech, AI, and self-replicating chemicals pose far greater existential risks. Given that we have no evidence of the survival of other civilizations and that we are rapidly progressing to all of the self-replicating risks, escaping our solar system would be prudent.
> or the terminally boring “return to the Moon”
Here are some of the exciting things which will happen with the return to the Moon:
– The confirmation of lunar ice and its characterization and implications,
– “Robbie the Robonaut” landing and telerobotically assembling a robotic base (and his twin is coming to a highschool near you),
– Enough lunar-derived oxygen and water production to support an astronaut indefinitely,
– This generation’s Man-on-the-Moon moment,
– The first woman to land on the Moon (think of how many girls will go into STEM!),
– The first Chinese to land on the Moon (think of the millions of Chinese who will go into STEM!),
– The first private astronaut landing on the Moon,
– The first dog on the moon…in its own space suit!,
– The first harvest from the lunar greenhouse,
– The first spelunking mission in a lunar lava cave,
– The first in-situ production of metal parts for robotic equipment,
– The landing of biologic materials for a lunar “ark”,
– Declaration of the first self-sustaining lunar colony.
> Once it’s cost-effective to go to orbit, the forces of exploration, economics, social flight, and wanderlust will push us much further. But first we must open the floodgates.
We are a lot closer to opening us space than many realize. SpaceX is making getting to orbit a lot less expensive than previously, especially with its Falcon Heavy and, if they achieve reusability, then that’s it. But costs can also be lowered with a “Lunar COTS” approach, in-space reusable vehicles such as a space tug for cargo and a large Armadillo-priced lunar lander, telerobotic operations, and lunar-derived resources. None of these require tens of billions of dollars. And the truly boring ISS shows that funding can be maintained across administrations.
Eniac, how do you stop the tip from drooping too much from the load? I like the idea though, but it’d need a very interesting gearing system at the hub for when you put a load on. Hmmm…
John Hunt said:
“Rather biotech threat, yes, but also nanotech, AI, and self-replicating chemicals pose far greater existential risks. Given that we have no evidence of the survival of other civilizations and that we are rapidly progressing to all of the self-replicating risks, escaping our solar system would be prudent.”
I concur with the general notion that humanity’s survival depends on the colonization of space and I too take the threat of biotech run amok seriously, but as for nanotech I am a little more skeptical. For years now I have been hearing about both the promise and the threat of nanotech and neither has yet to materialize.
DNA is a self-repicating chemical. By self-replicating chemicals are you meaning this term to be synonymous with nanotech or are you referring to something different?
Adam,
In lunar gravity and with a sufficiently short and fast sling, droop is very manageable. I once figured that a 3-5 g sling (which could be used for human transport) would be a couple hundred km long and droop a few km, which would permit building one without much of a tower given a mountain and suitable terrain. The moon’s curvature actually helps some. I cannot vouch for those figures, which are from memory, but they should be in the ballpark. A faster sling (for materials only) could be much shorter and would droop much less. On asteroids, there is no problem whatsoever with drooping.
For most of its length, the sling would be under such high tension that the effect of the payload sliding by at high speed should be minimal. We can let go before we reach the tip if necessary.
In all but the fastest and shortest slings the hub would turn at a leisurely pace, making it fairly easy to hook on the payload. Motor and gearing could resemble a standard carnival ride. Timing is important for control of the throw direction. For accuracy, there will have to be a mechanism to make small corrections to the sliding speed during acceleration. The coupling between sling and payload could be rollers, a gas cushion, or a block of ice.
The sling could also serve as an energy storage device, which could be very useful on the moon.
Is a starship a bridge too far? A wait of two hundred years or more certainly suggests that it is. Of course, we should be focusing our energy and space finances to colonizing Mars. If a new society can be planted, it will massively increase innovation as well as increase our survivability. DARPA, should also be thinking of ways of growing our economy. (Perhaps an international consortium going to Mars could do that?) America’s present faltering economy will not be able to defend our country or develop space. Consequently, our economy should be the number one security issue. If DARPA continues to think too far out of the box, it may soon find it that has little or no funding in its box – which would be sad, no flying Humvees!
More about the original masslauncer idea :
The military variant of a masslauncer is called a Rail Gun , and theese have reached accelerations of their bullets of the unbelievable kind. In theory a motor of this kind could be relevant even for a starship , given a good electric powersource , because i the vacuum of space the reaction mass could reach almost relativistic speeds , and because the ship might consume parts of its own structural mass towards the end of the braking process…such as the magnetic sail , parts of the masslauncer itself , and perhabs parts of the long term maintenance equipment and radiation shielding . And all other the stuff we never get to throw away !
a long time to wait?
we speculate it may be 100 years to build a star ship. Consider that the first generation star ships will almost certainly have to be in service for far longer, perhaps a couple of hundred years or more. The journey to the stars is just that slow. Therefore if we cannot sustain a project to BUILD one for 100 years, how can we hope to operate one ? The technology has to work well, and be sustained and renewed on a regular basis. The key is the institution.. we cannot have a NASA run the thing! On the other hand, I just visited my Alma Mater this weekend. Over 350 years as a major institution and still running strong and acting as one of civilization’s more subtle driving forces.
lets face it . we need more than a blog behind this guys and gals.. although here is where it might start.
suggest a modified model like Battelle( before the lawsuit to break it up as a not for profit) . an aerospace research institute sustained by grants and royalties, with top flight ( pun intended) scientists and engineers, all with a dream. and institution able to contract to us government, us industry and even friendly G20 countries. All with a unique charter, owned ( and directed by) by the staff that have achieved tenure, built to stay on mission.
Built to last!
Eniac,
What you’ve sketched is pretty sparse, so I’m wondering just how much you’ve thought this through (or that you’re quoting from another source). The reason is that there are some pretty enormous mechanical challenges in what you propose and that, in what you’ve written, isn’t addressed.
First, the kinetic energy of the payload doesn’t come from “sliding” along what I’ll call the spoke – I think this is what you meant by sling. There must be a transfer of angular momentum from the rotating mass to the radial (outward) momentum of the payload. That transfer is made at the interface between the spoke and the payload. In other words, there is a complex and changing large force at that interface. Ice or gas isn’t going to be good enough to effect an efficient, reliable transfer.
There are other problems. For example, the acceleration itself places a large force onto the spoke in the direction opposite to the rotation. Is the spoke “free standing” (only attached at the hub)? Unless the final payload momentum is small the bending moment on the spoke will destroy a free standing spoke. If there is a lattice-work of some sort to provide rigidity and strength in the rotational direction, there are still further challenges. If very rigid then the force will appear at the hub. This alone could add significantly to the support and drive forces already there. The lattice-work itself will require the payload to be axially non-symmetric (by mass) with respect to the spoke. That will create a large torque in two direction: twisting the spoke; and normal to the rotation. These must be dealt with.
This would take some detailed modeling and calculation to expose and resolve these issues. My guess is that this type of sling would only be able to transfer a small fraction of its angular momentum to the payload.
Another thing… not only is the release timing critical to determining direction of the payload, but also the exit velocity. The final velocity, because of the force between the spoke and payload, will be somewhere between the spoke’s tangential velocity and the payload final “on spoke” radial velocity. It’s complicated.
Ronald — what, not dictator… er, philosopher king for life? *laughs*
Since I find myself unwinding after a major grant submission and someone on this thread indulged in whack-a-mole, I will do the same — although I don’t like doing Remediation 101. I should say up front that I agree with Larry that research into such issues as sustainability, renewable energy, etc will help us both on earth and off it.
Tiffany and Christopher:
When you argue, it’s good tactics and strategy to use arguments that help your point. The sun will enter red giant stage in a few billion years, at which point humanity will be long extinct or have evolved to something unrecognizable. A nova explosion nearby will bathe our entire solar system, so any colonies within it will be as fried as Earth, with much less comfort.
One starship won’t help us evade extinction and we will undoubtedly face problems we haven’t considered, no matter how carefully we plan. We have to send many, and expect heavy-duty casualties. If this does not become an integral part of our thinking, we will never get to that launch pad.
Spaceman:
What’s holding us back, beyond political (lack of) will is basic biological issues. To give one example, since some here are still seriously advocating lunar colonies: we may be unable to have embryo development below a certain threshold of gravity. What is that threshold? We don’t know because NASA stopped funding these experiments more than a decade ago, essentially restricting itself to microbiology — an outlook that led to the “arsenic life” debacle.
Eniac:
Coriolis forces have real physiological repercussions and 3-5 g is past human endurance (as in: structural damage, not just a temporary blackout).
JohnHunt:
Self-replicating chemicals? What are these beyond nucleic acids within lifeforms? Epidemics can certainly put dents into species, although resistant individuals ensure an eventual comeback. However, if I had collected a cent each time someone started on the “grey goo” stuff, I’d be a very rich woman by now and could build my own starship. Hmmm… now there’s an idea. March of Dimes for Space.
The Moon is a dead end destination any way you want to look at it. We will never be able to live remotely sustainable lives there, and most of the items you propose are fancy whims for the idle rich — the same idle rich that are bringing the entire world back into quasi-feudal configurations.
Mars is a very different story, despite its greater difficulty. It’s a living world, and a potential home. Between that and its intrinsic interest, it’s a worthwhile destination and close enough to be(come) feasible. If NASA drops this part, as it may, it’s raison d’ être essentially disappears.
jkittle:
There is (well, was) an organization such as you describe; namely, NASA, before the administrators started distracting and overriding the engineers (something increasingly happening in universities as well; it’s the only personnel segment that’s expanding instead of contracting like the rest). The alternative is a priesthood, with all the dangers the term implies, including the “rolodex friends” syndrome we already witnessed at the 100 Year Symposium.
Athena Andreadis writes “Coriolis forces have real physiological repercussions and 3-5 g is past human endurance (as in: structural damage, not just a temporary blackout).”
Wikipedia states “Early experiments showed that untrained humans were able to tolerate 17 g eyeballs-in (compared to 12 g eyeballs-out) for several minutes without loss of consciousness or apparent long-term harm.” So I assume that the problem Athena states stems from tidal forces and not the acceleration itself.
As taken from the hub these forces do not seem large enough to worry us, so the problem must be due to beat frequency waves traveling down the spokes. Anyhow, this problem sounds so interesting that, surely, it merits that you give us a reference, and in particular one that can give an estimate of the limits of tidal forces that the human body can stand.
Rob, Athena is talking about long-term exposure to G-forces, not short durations. Indeed, one fellow named Stapp survived 96 Gs in a rocket chair. But it is another matter to try and live with such conditions.
If the Moon’s gravity is too light for current humans, would Mars be tolerable enough over time? If we don’t end up having our machines be the colonizers of the galaxy and beyond, we may have to genetically engineer humans to survive out there. But as I recall you saying in the past, Athena, that is no piece of cake, either. We may have to explore and enjoy space remotely while taking better care of Earth and trying not to overpopulate it in the process.
I think controlling population will always be unattainable. Restricting the number of offspring, requiring permits, etc. where do we draw the line? How often will we have to move the line?
Add to that we continue to try an improve our lifespans. Just the other day i was reading about how our children and grandchildren will be living to 150+ years.
No, I believe that venturing out into the galaxy is our future. Mars, with 40% of Earth’s gravity may or may not be suitable for long term colonization, but how about orbiting stations with controlled centrifugal gravity systems? In orbit around Uranus, those stations could be home to millions mining fuel in the upper atmosphere of that planet and using it to power the stations and would make an excellent base of operation for the building of interstellar craft.
In order to make an interstellar craft, we will need to take advantage of every accessible resource in our solar system, from gaseous planets to asteroid mining. Where we have long term mining, we’ll have people and robots. People tend to make and want to be close to their families. Artificial space habitats will be a part of our future.
Tony P said on November 9, 2011 at 13:15:
“I think controlling population will always be unattainable. Restricting the number of offspring, requiring permits, etc. where do we draw the line? How often will we have to move the line?”
While you make a good point that trying to get humans to curb their procreation urges or even use contraception is problematic at best, the problem is that unless something reasonably civilized and humane is done relatively soon, either an oppressive state and/or nature itself will cut down the birth rate, and chances are it will neither be pretty nor nice. People keep acting like Earth will just keep sustaining us as society is now indefinitely, but that eight thousand mile wide rock is anything but infinite.
Space colonization will not ease off the billions from Earth unless there is some kind of massive migration into space, which I do not see happening so long as governments are footing the bill for rockets and ships.
And while beings from Earth may indeed go on to expand into the wider galaxy some day, I have the feeling that not many will be the kind of humans we recognize now, or even human at all. We are just starting to get less parochial in our thinking about the future in space.
Ljk, the duration of exposure that we are talking of here is at most a quarter of an hour, so I do not believe that the problem is acceleration. It looks to me as if Athena is trying to denoting something that the English language has no word for, but that is similar to Coriolis forces. As you know, Coriolis force is not a force at all, but a necessary adjustment to expected motions from when you calculate using a function describing the acceleration of points of in the landscape of your interest that differs from their actual pattern of acceleration. The most similar problem that I can think of is that of extremities of the body experiencing sufficiently different accelerations as to produce some unnatural internal stretching. Anyway, a reference would illuminate the importance of this problem, whatever its actual nature.
@Athena:
Not sure where you get that from. Rob has addressed it pretty well, let me just add that many roller coasters and other carnival rides do more than 3g, and 5g is very supportable for the few minutes it takes to accelerate to moon escape.
@Ron S:
I’ll be happy to elaborate if it doesn’t bore everyone to death :-)
I have thought about this quite a bit, and will try to provide some more thoughts to address your very valid concerns. There is some literature on various sling devices, but I don’t think any of them is quite like this. The key here is not to have to spin up the sling for every launch, but to keep it running continuously and load it from the center. Maybe there is a fatal flaw, but I have not found it yet.
Transfer of angular momentum: The payload is free to move along the tether (I’ll call it that instead of spoke to avoid the mistaken notion of rigidity). The only force the payload experiences is orthogonal to the tether, and thus not all that “complex”. Yes, the tether has to absorb the force, in the short term through its tension and inertia, then longer term through the drive motor at the hub. The tether would be much heavier than the payload, to keep it from slowing down too much after each launch, and under very high tension, which should make it resilient to the impulse generated as the payload passes along. At the hub, there would be a (relatively) short rigid arm to transmit the off axis forces needed to transmit the long term angular momentum from the drive motor. The momentum for each launch would be primarily taken from the tether, slowing it down somewhat, to be gradually reaccelerated by the drive motor. Energy efficiency would be close to 100%, >80% if electric motor losses are included.
Ice or gas: I would be interested why you think ice or gas would not work. I favor gas because it is pretty clear it would work regardless of velocity, ice because it is simple and cheap, and rollers because they do not use consumables. Sure there are engineering challenges, but I can think of none that would be impossible to overcome. And, I forgot to mention that there could also be solutions based on magnetic induction. In the worst case, the free-sliding aspect can be dispensed with, at the cost of a 1.4 times higher tip velocity.
Yes, exactly, but the repeat rate could be high. Each launch will take 10-20 minutes, if I remember correctly. You may even be able to have multiple payloads on the tether at a time. Launch rate is limited by two factors: 1) How long it takes to dissipate disturbances in tether dynamics, and 2) the power you have available at the hub. What counts most is the energy efficiency (energy invested vs. kinetic energy provided to payloads), and that should be as high as any system could possibly provide.
It could help, or be necessary, to support the tether with a tensional latticework incorporating shock absorbers to avoid dynamical issues.
Right. You would need a way to make small corrections (a small brake on the payload, perhaps), and some fairly sophisticated computer model. If we can do adaptive optics, we should be able to do this. As I recall, the final radial velocity will be approximately the same as the tangential velocity, so that you need a tip velocity of around 1.4 km/s to launch to lunar escape. This is not too fast for currently available high tensile strength materials.
There are definitely no tidal forces here, and the “Coriolis Force” is what accelerates the payload. It points orthogonally away from the tether and changes direction quite slowly, about 10-15 minutes per revolution. There is no reason whatsoever it would be felt as anything other than a g-force. The device rotates at a much lower rate than a carnival drive, for example, which seldom kill people.
@Athena Andreadis
I was going to mention that the sun entering red giant stage is not a near term issue. The near term benefits of space travel and colonization include:
1. Continuing the great human exploration of new frontiers.
2. Providing children with a truly exciting future.
3. Harnessing new resources and sources of power.
4. Expanding the scope of human civilization.
5. Giving people the chance to experience space travel and see strange, exotic environments on other planets.
6. Giving people the chance to find new homes amongst the stars.
7. Ensuring the longterm survival of the human civilization.
You said that humans will either have gone extinct or evolved into something unrecognizable a few billion years from now- how do we know this is true? I have heard that humans are not evolving anymore since there are no long term environmental pressures on humans. Thus, we won’t evolve into short little people with weak bodies, big heads, and antenna in the future. Humans could go extinct in the future, but I was hoping to avoid that. A few billion years is a long enough time for humans to change considerably- but I would not assume that humans will become brains floating in jars just because “It’s the far future!!”. After all, evolution is a fairly random and messy process, not a steady march to perfection.
If we aren’t going to evolve into super-beings, we could always turn to technology to do it for us. Perhaps we could genetically engineer humans with bigger brains- Stephan Hawking suggested that, saying he doesn’t believe humans will remain basically the same centuries into the future. I have my doubts, especially considering the social factors of such an effort. You might end up with a real-life eugenics war.
Maybe we could replace our bodies with metal, composites, and circuitry- removing our brains from our bodies and placing them in an armored shell to become something like the Cybermen from Dr. Who. That way, we could free ourselves from disease and old age. We could shed biological needs and wants, forgo emotion, and become passionless metal people. Our strength would be that of an armored robot. We could walk into a vacuum without a spacesuit. Maybe we could upload our consciousness to a computer, leaving brains behind entirely.
Less extreme modifications are possible. Transhumanism could creep up on us as humans get more and more used to genetic engineering, cybernetic parts, and various other gradual improvements. Some groups might choose to adapt themselves to alien environments or even the vacuum of space, or to create humans resistant to radiation damage, etc.
Some scientists suggest that biological humans won’t go to the stars at all. Instead, we will upload our minds to computers. Re-engineered into intelligent machines, our descendant’s vastly scaled down starships will transport their consciousness without needing to provide artificial gravity, oxygen, or legroom. This vision of a sexless, body-less future isn’t very romantic.
As a machine intelligence, you can’t take a nice girl for a walk on the shore of an alien sea on an evening lit in bluish glow by a massive extrasolar gas giant rising slowly above the horizon. You can’t navigate a spacecraft with a powerful mass-conversion torch drive using your slide rule. Nor will you ever experience the acceleration of a launch to space quite the way a normal human strapped in a spacecraft does. You can’t experience the danger of climbing the mountains on Mars either.
Perhaps a machine intelligence would experience other phenomena that are just as wondrous. Maybe the solar wind would be a warm summer breeze and the vistas of empty space beyond Neptune a welcoming meadow to such a being, I just don’t know. I do know that a future as a machine being lacks the romance of warmblooded humans with problems we can understand and relate too, which is why SF tends not to portray futures where the human biological form is only a passing phase.
In a “Star Trek” style setting, vast starships carry humans from star system to star system and many planets have been colonized. Humans are still the same as they have always been, except that we have much better technology and a peaceful, tolerant society. Humans colonize other planets by either finding suitable worlds for human habitation, terraforming unsuitable planets, or using space habitats. There is a lot of travel, exploration, migration, and trade going on, so different planets are not isolated bubbles where humans can evolve in different directions from the rest of humanity. Nor is differentiation encouraged by genetic engineering or cybernetic adaptions. In this future, humanity as a whole remains the same species thousands of years into the future.
If other solar systems are colonized by one-way slow starships that bring a group of settlers who adapt themselves to their new environment and have no contact with other segments of spacefaring humanity, then I could imagine humans evolving in new directions, possibly by design. If humans keep in contact with other colonized planets with fast starships (high fractions of C), I don’t see that happening.
Do any of you have any thoughts on this?
Sorry, I missed this earlier. No, it is not that complicated. The final velocity will be the SUM of the radial and tangential velocities. The radial velocity increases with third order of time on the way out, and ends out to be the same as the tangential velocity in the simplest model. The final velocity is the vectorial sum and should go out at a 45 degree angle and have a magnitude of sqrt(2) times the tip velocity, or approximately 1.4 times.
@Chris:
Decades of travel time and many years of communication latency hardly encourage a lively cultural exchange. Any communication would be like history, to be learned from but otherwise not actionable. Travel would be practically non-existent, except for the purpose of colonization.
Eniac, surely calculation of the final velocity is only as simple as you posit above if these tethers were amazingly massive in relation to their payload (or rigid).
@Eniac
Perhaps not, but don’t forget time dilation. If travel at near light speed is ever cheap enough to allow a large number of starships to be launched, some people will chose to leap between generations as they travel between stars.
Many people assume that an interstellar empire or federation could never, ever exist. Considering the short attention span of modern society and the difficulty of interstellar travel, this seems like a reasonable assumption. But is it?
The biggest arguments against interstellar empires is the long travel times and response times between stars and the rising complexity of ruling a multiplanetary empire with millions of inhabitants. Poul Anderson once said, “Punitive expeditions would be nearly impossible, hideously expensive, and probably futile: You’d be punishing the grandchildren of a generation that seceded from the Empire, or even a planet that put down the traitors after the message went out. Even a rescue mission might never reach a colony in trouble. A coalition of bureaucrats could always collect the funds for such an expedition, sign papers certifying that the ships are on the way, and pocket the money…in sixty years someone might realize what had happened, or not.” Poul Anderson must have been in an unusually skeptical mood when he once declared that “even a hyperdrive cannot lead to a galactic imperium.” However, these arguments fall a little short.
In the far future, we might be capable of building ships that travel at nearly the speed of light, enjoying plenty of time dilation on the journey. If any sort of FTL travel is ever invented, like wormholes or warp drives, travel will be even faster. Much as radio, television, and air travel caused the Earth to seem to shrink, so will these new technologies cause the cosmos to shrink. By the time we travel the stars, we will be a solar civilization that harnesses the power output of entire stars- so we will have plenty of energy to power up starships and weapons with.
A totally STL empire will certainly build outposts and supply depots near important population centers. These bases could dispatch warship fairly quickly by command or local authority. This was how imperial Rome stifled revolt- a strong military governor backed up by several legions. Only the loyalty of the outpost to the emperor needed to be maintained.
It is hard to imagine a more effective means to discourage revolt by promising to punish the heirs of those who are tempted to revolt. Why start a rebellion when your descendants will hate you for it, and you won’t succeed in changing things anyway? As for corruption, supercomputer-bureaucrats don’t need money, will be programmed to serve the Emperor, and sophisticated enough to detect and report any attempted tampering with the system. Don’t forget that future humans will likely have much longer lifespans. A human bureaucrat will need a medically or bionically extended lifespan and will likely think twice before jeopardizing a millennial civil service career for a mere 60 years of luxury.
With faster-than-light travel, empires become as plausible in the galaxy as they are on Earth. A fleet of warships that travel at 1000 times the speed of light can travel from Earth to Proxima Centauri in just 37 hours, or cross a 1000-light-year diameter empire in one year.
The complexity of running a star empire seems rather daunting at first. The larger a population grows, the greater the number of possible interactions are. However, future supercomputers will be able to handle this massive amount of data. High level command decisions will still be in the hands of humans. With sufficiently powerful computers, very large empires are possible.
In this far-off future, humans may live for a very long time due to new medical treatments or bionics. A general who lives for thousands of years would not have a problem with launching a decade long military action.
To give an example of how extended lifespan can change priorities, I will give you an example. Let’s say that you, Eniac, are a Star System Governor with a lifespan of possibly thousands of years in the Fourth Great and Bountiful Human Empire that spans a distance of 1000 light years in the year 4267. Maybe you’d like to revolt, but you know that the nearest loyal military outpost will launch a punitive fleet with planet busting lasers that will arrive 50 years later. A modern middle aged individual might decide that it was worth 50 years of total power since they wouldn’t live much beyond that anyway, but you have a career that could last a centuries to think about. Would you decide to revolt, or to be content with what you have?
I’m not saying that an interstellar empire is certain to exist or even likely, but there are ways one could come about. The Tau Zero Foundation does look into ideas like near-light-speed travel or FTL travel that could make holding together a star empire a lot easier. Don’t just assume that “the distances are so huge, we could never have meaningful interstellar cultural exchange, ever!!”
If certain technologies come to pass, I could imagine an interstellar empire or federation forming. I could even imagine planet busting weaponry like Death Stars coming into use. Humans have a tendency to like to form pyramidal social structures, which an alien descended from a more solitary animal like modern day bears or squid would not have.
Here is an essay that explores the issues of an interstellar empire in much more detail:
http://www.xenology.info/Papers/GalacticEmpiresAres1983.htm
Eniac: “I’ll be happy to elaborate if it doesn’t bore everyone to death :-)”
Oh, go ahead and bore people! We need something concrete once in a while to distract us from too much evidence-free speculation (heh).
Eniac: “Ice or gas: I would be interested why you think ice or gas would not work. I favor gas because it is pretty clear it would work regardless of velocity, ice because it is simple and cheap, and rollers because they do not use consumables. Sure there are engineering challenges, but I can think of none that would be impossible to overcome. And, I forgot to mention that there could also be solutions based on magnetic induction. In the worst case, the free-sliding aspect can be dispensed with, at the cost of a 1.4 times higher tip velocity.”
I’m making a qualitative guess that the force between payload and sling/spoke towards the tip, where it reaches a maximum, would inevitably cause some rapid and extreme heating. Ice is slippery but not slippery enough, I suspect, and you’d soon melt it and lose your cushion. Gas also will be heated under those conditions and would require a exceptionally good seal along the full length of the sling. Bearings in rollers would likely perform even worse due to the much lower contact area.
Eniac: “…you need a tip velocity of around 1.4 km/s to launch to lunar escape. This is not too fast for currently available high tensile strength materials.”
Perhaps, though that would requires some calculation. You seem to want a non-rigid sling (call it a spoke if it is rigid?) that is in tension due to its rotational motion. Tension will be increase towards the hub so more material needed there. It can taper in a fashion towards the tip, but not so much that the mass/length deflects under the payload, to which it must apply a force without bending (much). Rigidity is therefore more critical towards the tip. Non-metals such as, say, kevlar, need a sheath of some sort as an interface to a sliding payload; strong in tension but easy to cut or abrade, and to rough to avoid friction, gas loss, etc.
Eniac: “No, it is not that complicated. The final velocity will be the SUM of the radial and tangential velocities. The radial velocity increases with third order of time on the way out, and ends out to be the same as the tangential velocity in the simplest model. The final velocity is the vectorial sum and should go out at a 45 degree angle and have a magnitude of sqrt(2) times the tip velocity, or approximately 1.4 times.”
By complicated I only meant that it might be non-intuitive. It’s easy enough to calculate — as you’ve done — though I didn’t bother to do so myself. What I meant by my cryptic description is that when viewed from a distance down on the hub axis that the payload trajectory is an open spiral that terminates (transitions to ballistic flight) at an angle between (from the observer’s perspective) an angle that is between radial and tangential. Of course this asymptotically approaches a radial trajectory as the flight continues.
I’m surprised you found that the exit angle is constant despite the configuration. Interesting. In practice this will depend on the rate of change of the sling (spoke, or whatever) deflection at time of exit.
@Rob, Yes, you are right, of course. But the tether really is heavier than the payload, so the simple model should give estimates that are approximately correct.
I am sure we will eventually turn to interstellar exploration because — quite literally — it is in our genes. Once we have explored and colonized the solar system, humans will be itching to go beyond it and we will have perfected the technology and science to make that both possible and practical. Will we have exceeded the speed of light? I hope so, but whether we have or have not we will still go to the stars. This will not be an answer to the current or future population problem here on Earth. Sadly, unless we achieve some technological breakthrough right out to Star Trek, it will be completely impractical if not impossible to send large numbers of humans away from Earth outside the solar system.
Initially I would expect we will send unmanned probes to the closest 5 to 10 stars found to have suitable planetary systems by our endlessly improving space-based telescopes and remote sensors. In fact, I predict that we will begin sending unmanned probes to other star systems long before the end of this century — and I don’t mean Voyager. Unless we have broken the light barrier, human missions to the stars will have to be one way for the foreseeable future. Depending on the transit time to the destination, I would anticipate human occupants will be sent either in hibernation or as frozen fertilized eggs. It is also possible that there will be a combination of these techniques where a small number of humans will be send in hibernation and they along with the ship will raise the first generation of human colonists and crew once they reach their destination. In my opinion, multi-generational star ships are simply too massive to be practical and the psychological and sociological issues are too problematic to ensure success of the mission.
For missions using frozen fertilized eggs, the eggs will gestate and be “born” as the ship approaches the destination solar system. Robots and preprogrammed leaning/training techniques far more advanced than anything we have today will raise and nurture the young humans to adulthood and give them the skills and attitudes they will need to begin to colonize their target solar system. Beyond the necessarily limited stores that were sent with them, the ship they are on will have the technology to manufacture, fabricate or synthesize anything they need out of resources found in their destination solar system. Except for robotic parenting, the same constraints will apply to those missions where the human crew was sent in hibernation.
It is likely that the first few generations after their arrival in a new solar system, humans will live in one or more space based habitats allowing them to live in a secure environment while they explore the solar system, consider whether any of the planets are suitable for colonization, mine its resources, and look for life that may already exist there. The hazards they will face are unknowable and having a safe and secure habitat to live in and operate from will likely be indispensible. It is quiet possible that some or even most of the colonies we send to other star systems will continue to live in space-based habitats rather than establishing permanent colonies on planets with hostile environments. Only time and the circumstances they discover will give us the answer to that.
During this time a communications network will be set up allowing them to contact and communicate with Earth and all of the other colonies in the expanding realm of mankind. Undoubtedly, a massive period learning will ensue – lessons learned, wonders discovered, emerging hazards, the possibility of intelligent life. Presumably technology and science will also continue to advance on Earth and throughout our home solar system. This knowledge will also be disseminated to our far flung colonies. Will humans continue to evolve during this time? I am certain that they will and the process may become quite rapid. This evolution will most likely be driven by two powerful lines of development: 1) Our own ever advancing knowledge of genetics and ability to manipulate our genetic structure; and 2) Our ever increasing ability to interface more effectively with our technology at the molecular/nano technology level. The combination of these lines of advance will produce amazing progress in our capabilities – including intelligence, life spans and improvements in our ability to survive in the hostile environments in space.
At some point, depending on how successful their mission has been, the various human colonies may mount manned interstellar missions of their own to other nearby stars. By then the propulsion systems may have advanced to the point that sending a human crew that is not in hibernation may be practical. Eventually, I hope we will have discovered faster-than-light (FTL) propulsion that will make a coherent and expanding human “empire” possible and allow travel back to Earth so that we may all share in the wonders that will have been discovered – out there.
BUT, until we get our act together and start to make this 100 Year Starship Study a reality, all this is pure fantasy. So let’s get moving.
Whenever the topic of sublight interstellar empires comes up, I always feel the need to mention Permanence, by Karl Schroeder…
Depending on the culture, an interstellar empire may or may not be feasible. An interstellar hegemony, held together through force, may not work; while an interstellar caliphate, where the binding force is religion, may do.
With ships that can travel at 0.6c (0.75c from the perspective of the crew), an ship travelling from here to Eridani would take about 15 years from the perspective of the passengers. Certainly, no-ones going to be holidaying there, but emigration may be possible. The Centauri run would only take 6 years, which suggests that someone may actually be able to move out when they’re 16, spend their life working in another star system, and retire to Terra. Or Luna. Or wherever they wish to live. As for the crews of such ships, they could sign on for a 20 year tour of duty, after which they would retire. If stars, brown dwarfs, and superjovians are spaced by 2-3ly (travel times 3-4 years), it becomes even more viable… each system may only trade with it’s immediate neighbours, but the net result could see high value low mass items (paintings, wine, drugs, computer components) moving between stars spaced a couple dozen lightyears from each other.
As for currency issues to allow for trade, perhaps a universal currency could be effected? I’m thinking it could be backed by property holdings on every world. If you wish to transfer your money between worlds, the branch on your planet will send a message ahead, with a secure code, detailing the transaction; a duplicate copy of this message will be taken in person on a data pad. If the two match, you can access the funds.
As for what sort of goods they’d trade… with shipping costs being optimistically at #10/g (where # is a holding unit for the currency), say comparable to todays price to orbit, you need very low mass products people will be willing to pay a lot for, and which would be cheaper to ship in than produce insitu. For a small colony, drugs may fit this role – if only the active ingredient is sent, it may work out to maybe #2/dose ignoring profit, which may be cheap enough for people to import it (if it’s one that people need a 200mg dose of daily, then each person will get through 73g each year; it’s not going to be enough for a dedicated trip, but as part of an existing trip it could work? If 10k people need it, then its 0.73 tonnes required each year…). Paintings could be another – if they mass in at 1kg, the costs come out to #10k as a baseline. Clothing may even be possible at such low low prices, given the prices that are regularly charged now for low mass items. Drinks, such as wine, could age during the trip, perhaps?
I do think a sublight civilisation is possible to achieve, even with the information transmission lag. Where military power can’t be projected, economic power will have to suffice. Given a choice between remaining in the Federation, recieving all the latest advances etc, and leaving and becoming an ignored backwater system…
As we get more information from Kepler and similar more advanced future telescopes and probes, the chances of finding a rocky tectonically active planet around the mass of Earth orbiting a G-type star in the habitable zone get better and better. From all the planetary discoveries we are making, this type of world may not be that rare, intact we may be teaming with them in this arm of the galaxy. In the next decades,not only will we have the ability to detect these planets, but we’ll be able to determine not only their composition, but how much water it has and it’s atmospheric content.
Now in a future where overpopulation is a huge concern and governments are preparing to take drastic measure, or maybe they already have, would not a discovery like this be an enticing and worthwhile endeavor to check out? Even colonize?
I think Stargazer nailed it exactly.
Christopher Phoenix says “I have heard that humans are not evolving anymore since there are no long term environmental pressures on humans.”
Those who think that humans are under no evolutionary pressure are not considering sexual selection. Humans have many aspects that work as secondary sexual characteristics. Two are physical attractiveness, and intelligence. The nerd theory would suggest that intelligence is selected against, and so would the idea that intelligent people have fewer children. However, I conjecture that a major driver in the evolution of intelligence was sexual selection, and that it is still operating. Consider a high gravity world. Perhaps advanced medicine would insure that no one dies of gravitational stress. However, a robust build that allows one to be more active would still be more attractive, if only because of the activity it would permit.
” However, a robust build that allows one to be more active would still be more attractive, if only because of the activity it would permit.”
This would have to be balanced against the possibility that a more stocky build may be considered less feminine, however, and thus less attractive in a society that has an ideal of feminine beauty. Given how changeable human perceptions of attractiveness can be, I’m not sure sexual selection is going to be a major player.
When it comes to evolution, we may be dealing with a sort of punctuated equilibrium: chance mutations combined with inbreeding among populations where that mutation is common. For example, consider the evolution of the Wookie… people, rejected from normal society because of a mutation which causes Hypertrichosis, find solace in each other and join together. Their children inherit the same mutation (yes, I know it would have to be a recessive mutation for this to occur in all of their descendants…); maybe, when the ticket prices fall low enough, they will move en masse offworld and found their own colony. Given a few generations, it would make sense to recognise them as a subspecies, and after the collapse of the first Terran Empire, the subsequent re-discoverers of the planet and it’s natives may not recognise them as being human. This is just one of potentially many human-derived “species” which could inhabit the galaxy. On the outer planets, autism may be a significant advantage, leading to the Autists growing strong there, with their more sensitive senses. Who knows? There is as much physical difference between a Vulcan and a Human as their is between a European and an Asian. Maybe human genetic tinkering among other intelligent animals may result in a sufficiently advanced Octopus civilisation – now that would be truly alien.
If Asians had lived on Mars, and Europeans on Terra, would it not be a reasonable guess of explorers from one planet that the other planet was inhabited by another species?
Also, what were we talking about again? I tend to get sidetracked into Hard SF discussions whenever discussing interstellar colonisation… they’re not that different after all…
@Tobias Holbrook
That is exactly what I mean. A sub-C civilization is possible to achieve, even if travel times are long by our standards. Even sub-C trade can be common.
It is a lot more likely that human colony planets will held together by economic ties than by galactic imperialism. Your colony planet can be part of the Great and Bountiful Federation of Human Worlds and have sub-C starships regularly arriving with passengers and various goods to trade, or you can be an isolated backwater system. The most important trade item is probably information- which would include technological advances.
As for the Wookies… that could explain why there are so many humanoid species in some SF universes!!
@James Blodgett
That doesn’t change my point- we are not steadily evolving towards limbless blobs. Hopefully we will not end up like this prediction of H.G. Wells by the time our sun swells into a red giant.
http://davidszondy.com/future/man/man_million.htm
Information I can see, beamed by laser, one-way only with rare exceptions. My guess is it would be free, though, because of the difficulties with managing orders and payments (see below)
Passengers and freight will be very rare. Would you go on a decades-long trip to a place you only have many years outdated information on? Visit relatives that may well be dead or gone when you arrive? The only conceivable purpose for travel, in my mind, is to leave everything behind and set out for the unknown. This would usually happen in the form of colony expeditions to settle new systems, although emigration from one settled system to another may also be attractive to some.
About freight, imagine the following: You live at Alpha Centauri, and you want to order a hot item from Earth on Galactic Amazon, from a catalog or advertisement you received in your e-mail. You hope your item will still be in stock (and Galactic Amazon still in business) when your order arrives eight years after the catalog was sent out. Of course, they ask you to send payment with your order, and eight years later you will get notice on whether your payment was accepted and the order shipped. If so, your item arrives a few decades later on the regular freighter. Unfortunately, in the meantime you have forgotten all about the order, and the item isn’t really so hot anymore…
Does anyone have any idea what sort of physical item would merit the inherent energy content necessary (or if on a slow boat, the inherent cumulative interest rate on capital employed) for interstellar trade. All I can think of is magnetic monopoles, and Sol seems to be (mined) out of these already. Art would only really seem to work for artists that become far more famous outside their home system, and I’m not sure that that would be common.
Eniac – you appear to be assuming both relatively low velocities, and current known spacing between stars. Should craft be able to achieve ~60% of c, and suitable bodies are spaced 2-3ly from each other rather than 4-5, that changes the picture dramatically.
Of course interstellar trade wouldn’t be like Amazon. It would be more like current markets – a company will import items regularly from a neighbouring system, and will stock the item until it is sold. Not every system has to swear allegiance to Terra for this, they just have to stick together with their immediate neighbours. It won’t be your forefathers galactic empire, that’s for sure. The biggest pan-imperium authority would be the Bank of Terra, with holdings on every world, with maybe Centauri Starlines coming in a distant second.
@Eniac
As Tobias Holbrook said, you are assuming relatively low velocities. Your “Galactic Amazon” is an example of modern-day “instant gratification” thinking that holds back space exploration. Modern people don’t want to work at a goal for years before getting a possibly-massive payoff, they want everything NOW.
Of course interstellar trade will be nothing like internet businesses. It will probably be a lot more like the merchant expeditions of old, where ships might be away for years and goods traveled along long overland routes. There will have to be something of great enough value to trade, similar to how silks, spices, teas, and porcelain drew traders to China. The greatest benefit will be the exchange of knowledge, ideas, cultures, and maybe even zoological specimens between different planets.
Your vision of isolated worlds just doesn’t fit with human behavior in history. People always have a fascination with faraway places and different cultures, as well as the goods they can obtain from these distant places. In a future where starships can attain 60% C or higher and some are privately operated, someone will choose to visit other planets. There will be great interest in news of other worlds. If there are valuable items to sell, perhaps someone might choose to make a decade long voyage to obtain them- just as Marco Polo went to China.
A “trader culture” could spring up with people making the run between different planets with goods to trade for fuel, supplies, and more goods to trade at other planets. The traders will have to purchase items that are valuable and in demand at their destination. It might be the work of a lifetime, but if a single voyage can make you very rich, some will take the risk.
A merchant moves things from a place where they are cheap to a place where they are worth more. Pebbles on one planet could be valuable gems on another. What is considered a nuisance plant on one planet could be highly valuable on another. The trick will be selecting the cargoes that are worth more, and the trader that guesses right might make a very nice profit. It would be barter only- money won’t be money except on the planet it is issued. Make the right guess, and you could end up very wealthy and retire on the floating cities of planet Sky. Get it wrong and lose your shirt.
Maybe floating-tree wood from Darwin V is in great demand on other planets, and there is no place to obtain floating-tree wood except for Darwin V.
Alice, who lives on Earth, decides to set out on an trading-expedition in hopes of making a good profit and seeing some strange worlds that she has never seen except in holoimages. So, she buys a cargo of luxury items (fine wines) and rare antiques and makes a run to Alpha Centauri. She manages to sell these wines for a good price to wine snobs at Alpha Centauri- those replicators just can’t reproduce the fine qualities of wines from the soil of vineyards in southern France- and the antiques to wealthy collectors. With the profits, Alice buys an A.I. expert system based on advanced spin-chips manufactured and taught at Alpha Centauri.
Alice then sets out to a desolate colony on the planet We-Made-It. She sells the A.I. expert system to the colony for a cargo of fire-pebbles, opal-like stones formed by dangerous lizard-like creatures referred to as Clay’s Dragons after their discoverer and first victim. She also obtains various botanical and zoological specimens for universities back on Earth.
Alice then sets out back to Earth to sell these fire-pebbles for a great price as highly valuable gems. Many years will have passed, but that doesn’t matter to Alice. She experienced plenty of time dilation on the trip, so she has not aged much, and she has reaped the wealth of Midas in this one trip.
See? Even at sub-C velocities, it is possible to imagine someone making a trading expedition or simply hopping from planet to planet. Leaving everything behind and setting out on a long voyage will appeal to some people. In fact, this sort of voyage would be much more exciting than a routine 3-day business trip to Tau Ceti via wormhole. You’d see new places, do new things, take risks- this sort of thing appeals to some individuals. All in the name of fun and profit.
Then again, you might suffer an engine breakdown and end up indebted to the inhabitants of some faraway colony and forced into slavery. Maybe the deflectors will fail and some speck of dust will end your trip really fast. Maybe you will calculate wrong and your cargo will be worthless. There will be those who fail, due to lack of luck or miscalculations.
As for actual technologies- maybe Alice’s ship hitched a ride on a larger interstellar craft or rendezvoused with an interstellar cycler. Maybe Alice’s ship has a torch drive fed with a ramjet of sorts. Maybe Alice’s ship has inertial mass cancelers that reduce her ship’s mass to almost zero so her impulse engines can propel it to high velocities much more easily. It is a pity that SF writers don’t tend to explore universes where sub-C interstellar travel is common but FTL travel is impossible.
When it comes to non-beamed propulsion, I’m not sure energy costs actually apply in the normal way, rather than fuel costs. It’s a bit like arguing against a Bussard ramjet simply on the grounds that it would have more kinetic energy than human civilisation has ever used a few years into it’s operation…
For example, look at Methane. Methane gives 15.3kWh when combusted, and I seem to recall Entering Space gave a figure of $0.13/kg for Liquid Methane? This would, assuming perfect electricty generation, give a figure of 0.85 *cents* per kWh, much lower than current energy prices. It doesn’t.
A Ram-augmented rocket using Lithium fuel, stored as solid rods to avoid the mass of tanks, could achieve 20-30% of the speed of light with reasonable mass ratio’s, if my Starflight Handbook is to be believed. If we design it right, we can maybe reach velocities of 50-60% of c with mass ratio’s in the low thousands. Total payload may be on the order of 0.01% of the fuel mass. If biological mining of cometry cores proves feasible, and we get costs of maybe #10/tonne for our fuel, then our baseline price only works out to #100/kg for cargo. At this price, exotic foods, clothing, and such, becomes plausible to ship – even at #1000/kg, they may well be economical. Highly advanced artificial organs are another possibility – you’re quite likely to be able to easily find someone willing to spend #10k on an artificial heart. I wouldn’t be surprised if we could get viable interstellar shipping at #10 per gram…
Don’t misjudge the capability of human beings for conspicuous consumption. The local planetary governor will want to impress people, and what better way to display his wealth than to have a spread of fish from the Gliese 581 system, with goblets flowing with Centauri wine? Sure, it would cost quite a bit, but it’s evidence that he’s got the money…
Mind expansion
by Lou Friedman
The Space Review
Monday, November 21, 2011
My mind got a chance to wildly expand a few weeks ago as I participated in back-to-back meetings investigating big ideas in space. Mind expansion is good: it psychologically diminishes today’s political problems (like the NASA budget) and program setbacks (like Russia’s Phobos spacecraft loss).
The two big ideas were moving an asteroid toward Earth for human exploration, and interstellar flight. The two meetings overlapped and for me were separated only by a cross-country red-eye flight—a small constraint on mind expansion.
The first meeting was an Asteroid Retrieval Mission workshop sponsored by the Keck Institute of Space Studies at Caltech. The second meeting was a public symposium sponsored by DARPA and NASA in Orlando, Florida.
The best way to advance ideas for interstellar flight now was to accept that humans would be best left at home (or at least in our solar system).
Interstellar flight is a vision for some and science fiction for others. I recall a discussion I had with Freeman Dyson a few years ago about whether we were further from interstellar flight than was Leonardo DaVinci from the airplane.
I thought so. But DARPA, with a little cooperation from NASA, conceived an idea called the 100 Year Starship (100 YSS) to create an organization that would focus the vision by public engagement and technical studies about sending humans on the ultimate voyage. The Orlando symposium attracted over 500 people over three days discussing many aspects of interstellar flight (see “The journey of 100 years begins with a single weekend”, The Space Review, October 10, 2011).
Full article here:
http://www.thespacereview.com/article/1973/1