Why think seriously about mounting an effort to reach the stars? In yesterday’s New York Times, Dennis Overbye runs through some of the basic drivers:
- The discovery of a habitable planet around a nearby star would create intense interest in sending a probe or, depending on how technology develops, mounting an expedition
- The demands of human nature include a basic restlessness that has always impelled us to explore
- The danger of a future impact from an asteroid or other space debris will force us to think not only about how to mitigate the threat, but also about a ‘backup’ plan for humanity
The article is worth looking at for the gorgeous Adrian Mann illustration alone — it shows a future starship on a ‘shakeout’ cruise near Jupiter. Overbye then goes on to discuss the 100 Year Starship Study and its upcoming symposium, with plentiful references to Project Icarus and the Tau Zero Foundation. It’s good to see the press continuing to focus on the real goals of the 100 Year Starship Study, given that Jill Tarter (SETI Institute) is quoted in the article as saying that some of the proposals for talks she has seen have been a ‘mixed bag.’ And she adds “Maybe you have to be a little bit crazy to think about this seriously.”
Or maybe not. Overbye refers to possibilities that are well within the realm of known physics even while they challenge (monumentally) our current engineering skills. I was glad to see reference, for example, to the kind of enormous solar sails that, boosted with a close pass by the Sun and made of incredibly thin and reflective materials, could get us to the Alpha Centauri system in a millennium. And although he isn’t mentioned by name in the article, Robert Forward’s ideas on ‘lightsails’ or ‘photon sails’ that would be pushed by laser or microwaves make an appearance, as do ion drives. Forward envisioned cutting the travel time to decades.
All of this means that propulsion systems galore must be on the table if we are looking toward a starship launch that might not occur in this century. Overbye refers to Marc Millis’ term ‘incessant obsolescence’ in terms of how technology may change as we pursue these studies, but what Millis really means by the term is the possibility that a starship launched with the fastest technologies of its day might eventually be caught by a faster one launched much later, leading to real questions about how long to wait before launching anything. It’s interesting to note that Andrew Kennedy, who has written about what he calls the ‘wait equation,’ will be a speaker at the upcoming 100 Year Starship Study symposium to be held in Orlando at the end of September.
“The agenda ranges far beyond rocket technology to include such topics as legal, social and economic considerations of interstellar migration, philosophical and religious concerns, where to go and — perhaps most important — how to inspire the public to support this very expensive vision,” writes Overbye, who calls the study “perhaps the ultimate startup opportunity.” Indeed, and the multi-disciplinary approach demanded by the challenge of starflight may be one of its greatest attractions. It forces us to acknowledge that if we are seriously talking about sending humans on what could be generations-long journeys, our investigations have to range far beyond propulsion into fields like biology, environmental science, sociology and psychology.
David Neyland (director of tactical technology for DARPA, and the man behind the 100 Year Starship Study) likes to talk about the tools we have now vs. our theoretical knowledge to develop them further. Would Einstein and Marconi have been able to come up with communications devices like cellphones if asked to sketch out a way for people to stay in touch in 1910? They surely had the scientific knowledge but were not at a position to foresee the engineering. The challenge of starship thinking is even greater. We don’t know for sure that we’re asking the right questions, making the need for divergent voices at the symposium that much greater.
But I like what Kelvin Long, founder of Project Icarus, has to say. “A lot of us are quite young. We grew up hearing about the Apollo program,” he said. “We want to be part of a significant journey. We personally think we may be doing something important, driving humanity out to the stars.”
If you’re intrigued by the ‘wait equation,’ see Kennedy, “Interstellar Travel: The Wait Calculation and the Incentive Trap of Progress,” Journal of the British Interplanetary Society Vol. 59, No. 7 (July, 2006), pp. 239-247.
Comments on this entry are closed.
The “incessant obsolescence” thing is based both on the assumption that starship launches are just to come first and on the assumption that bypassing starships cannot share their new technology with the bypassed starship and modify it. Both those assumptions are false. And if the line of reason is extrapolated far, far beyond the speed of light, travel times will become negligible compared to the time it takes to see what you want to see at the destination.
Aren’t the three “drivers” Overbye notes better arguments for Mars than interstellar travel?
@Tulse : I think they are great arguments for getting us moving, in whatever direction. Mars is likely to happen this century (if we listen to those arguments). I think very few people are talking about starting to build a starship with Falcon 9 launches just yet, though I’m very happy for people to be thinking about the technical challenges involved.
In general though, I had to chuckle at Jill Tarter from the SETI Institute citing a bit of ‘craziness’ in being interested in starship planning. Pot, kettle, etc. .. I used to be a big advocate of SETI, but these days I’d personally rather sink what’s left of SETI budgets into starship studies, or even better, into a moon base or a manned Mars program.
Here’s one – let’s get a serious radio astronomy installation funded and built on the lunar farside…. and THEN fund a SETI program using that hardware. Come on, we could even make this an automated facility, if manned programs scare people with their expense and risk.
My take on that is that before we ever mount a serious interstellar mission, we will have developed a Solar System-wide infrastructure that will of course take in Mars. One step at a time, in other words, but the overall theme is going further and further out. So I don’t really disagree with Overbye.
Increasingly I see the problem of of interstellar flight as equal parts biological and engineering challenges.
If our evolution-imparted behavioral drives were different perhaps we would be happy to build and board a space craft that takes 1,000 years to reach it’s goal. Along the way maintaining a diverse ecosystem ( for a flight with a crew that is awake) or maintaining a biological stasis system ( for hibernation) would all be important.
living longer would be part of the project but also developing a society able to live in space and feel “at home” would be critical . Life on the journey must not be vastly inferior to the life after arrival ( see for example the book Red Mars) . For a society with engineering and social structure able to live on the huge number of Icy dwarf planets/ large “iceburgs” in our system, interstellar flights seem a trivial mater. Send your world adrift in the direction of an “ice floe ” concentrated around the perimeter of any interesting and nearby star system. No need to find another earth if we do not require a earth-like planet to live! Teraforming as an indoor sport! Indeed, we already terraform our personal environments!
From earth to asteroids to mars to the Jupiter Trojans to the Kuiper belt to the scattered Trans neptune objects to the ort cloud. The only reason to go to anoher star then is to find dense collections of dwarf planets and small icy bodies. -and to take a close look at the marvels of life evolves around other stars, perhaps still trapped on their warm and comfortable “habitable” planets. And show pity for the trapped souls unable to explore the universe as it really exists.
A space-based civilization would comprise a wide-range of group sizes and space-exploration capabilities, especially delta-vee. Smaller groups, analagous to covered-wagon parties, would be going slow, trickling out through the Oort Cloud. Larger groups, more analagous to our space program, would be going fast (~0.1c) to the nearest good prospects, particularly Epsilon Eridani, which probably has far more asteroidal matter than the Sun, crammed into a smaller solar system. Only a century away!
Hibernation capability will be the inevitable result of very long life, with a large fraction of the population ‘asleep’, as Arthur C. Clarke predicted, awaiting interesting events. Waking up around another star would just be a more expensive option, guaranteed to provide adventurous novelty.
The huge energy cost of fast flight would be well repaid by the prospects of rapid population growth, each colonist the eventual ancestor of millions, as long as the destination system is matter-rich. Since energy is wealth we would expect the richest outliers on the income histogram to be able to pay for their own passage, the way Arnold Palmer has his own Gulfstream jet.
Matter-poor systems such as Sirius and Procyon would only be destinations for multi-century flights by large long-duration colonies, ready to adapt to the equivalent of barren deserts. A much bigger colonization party arriving centuries later would still outnumber a small group that was unable to grow sufficiently during the catch-up time.
Since ultra-large space telescopes are far cheaper than space-probes, we can expect to know the good and bad locations long before we can get to them.
Paul or Marc if anyone says we cant afford Mars or Icarus at the 100 year starship conference………How much better off are we for maintaining the Wall Street Aristocracy
I think Tau Zero could put it to better use!
> The danger of a future impact from an asteroid or other space debris will force us to think not only about how to mitigate the threat, but also about a ‘backup’ plan for humanity
Compared to the threat of our own self-replicating technology, the threat of asteroid impact is very small. We already have people designing synthetic life. Researchers are attempting to figure out the basic principles for a self-replicating chemical and they’ll likely publish their findings for all to read. In time, engineering nanotech devices will be routine and will give great incentive to nations to be the first to develop a nano-super-weapon.
By contrast, we are steadily decreasing the number of unknown large asteroids. The typical asteroids we are now discovering are small enough that they can’t pose a global catastrophe. It’s been a very long time since we were struck by one large enough to cause general extinction. And even if we were so unlucky to have something coming in from the Oort Cloud, our telescopes would be able to detect it at least months in advance giving time for evacuation and even securing hydrocarbon-powered lighting for growing plants even if there were a decades-long winter. Finally, we don’t have to travel to another star to survive an impact. We could just colonize Mars.
Would Venus make for a better world to terraform than Mars? It is on the inner edge (towards Sol) of the Habitable Zone and has the advantage of being much closer in mass to Earth than the Red Planet. Of course if Venus has as many active volcanoes as predicted (~10,000), that might complicate things a bit.
This all assumes we will still need to make other planets Earthlike as preferable places to live upon.
ljk: “Would Venus make for a better world to terraform than Mars?”
No, I really don’t think so, unfortunately.
Venus is indeed a more earthlike planet in mass, but that is about all the good news. Apart from the fact that its day is about as long as its year (about 8 earth months), it is not “on the inner edge (towards Sol) of the Habitable Zone”, but well within its inner edge.
In fact even earth is rather close near the inner edge of our HZ. According to virtually all HZ estimates that I have read about, our sun’s HZ extends from 0.95 AU (most optimistic one said 0.93) on the inside to at least 1.2, or 1.5, or … Au on the outside. In other words: fuzzy on the outside but sharp delimited on the inside.
That is also most likely the reason why Venus lost nearly all its water: through photo-dissociation. All water present above, on and in Venus, would constitute a layer of only some 15 – 20 cm (on Mars probably some 150 – 200 meters).
And that is precisely the major problem with Venus: its chronical lack of water. Zubrin once calculated how may Kuiper Belt comets would be required to provide enough water (and speed up its rotation somewhat through impacts) and the result was humongous, truly showstopping, also in energy requirements.
Compared to that, terraforming Mars will be a walk in the park, target practice for other planetary systems. There is water, plenty of CO2, a reasonable temperature to start with, and, because it is a smallish planet, terraforming would not take so long. My major concern with terraforming the Martian atmosphere would be a possible lack of N2 though. You don’t want an O2/CO2 atmosphere.
Everyone seems to have given up on terraforming Venus from the moment the density of its atmosphere was realised. I suggest it an interesting exercise to assume that Venus is eventually found to be the best subject for this process, and then work out what contemporary clues we missed.
To me, our clearest mistake was to equate the zone in which natural geochemical and biological process can keep a planet in very long term equilibrium, with zones in which a minimal investiture of effort can create a thriving biosphere for a few million years.
I also note that gravity is the hardest parameter to change, and its strength seems a better match to human needs than even terrestrial strength.
True, the cost of moving so much carbon dioxide, or transforming it into another form such as carbonates, is prohibitive, but this just means that another way was found. Perhaps a parasol was used to place the whole planet in umbra until the atmosphere liquefied. Even if not, it is clear that a new ground level layer must have been floated over most of the Cytherean atmosphere, and then the composition of the remainder changed.
That remainder would have to be enriched in water vapor, and to that purpose meteorites and comets would seem so cost effective as a source, that I see no problem there.
There is still much I do not understand, such as how the mass of high pressure CO2 beneath the new artificial surface is stabilised, or how lakes of water could be supported on this surface, but I’m sure there must be a way.
As I understand, nitrogen is not needed. A pure oxygen atmosphere at the same partial pressure would be good enough for breathing. The CO2 would be removed (and indeed turned into oxygen) by plant life, if it can be established. The greatest concern here is the lack of water. There just isn’t very much, and it is all frozen. Even if it wasn’t frozen, or could be utilized in that form, it is not clear if there is enough to sustain sufficient plant cover. Furthermore, photosynthetic splitting of CO2 is coupled to that of water, and for all I know the water could run out first, while there is still too much CO2 left.
Eniac, your last post brings up the question of whether terraforming is best employed to optimise conditions for growth of our food crops, or for our own experience of the great outdoors. I fear that if we try to do both with Earthly ecology, we will need Earthly levels of insolation.
In any solution to the problem, Mar’s water inventory looks too high (current estimates are around 30m), and loss under any conceivable scenario due to photodissociation looks too slow, for humans as a species to worry over.
If the answer turns out to be to stick with current levels of sunlight and optimise for plant growth, then high CO2 seems no problem, but Earth life seems very inefficient at fixing nitrogen. Also nitrogenises are inevitably found to only work under strictly anoxic conditions, and here the minimum amounts of oxygen needed to provide a sufficient ozone layer will surely place the O2/N2 ratio very poorly for such purposes.
Another clue that Mar’s poor nitrogen inventory is a decisive factor may be what would happen if you remove all life on Earth. It turns out that the net effect here would be for the continuous production of nitrates until almost all the oxygen is gone… so, contrary to the expectations of we land-based life, denitrification is the dominating effect of life on Earth. We would need this effect to be transferred to the new Martian ecology or our biosphere would soon collapse.
Implications of Computerized Intelligence on Interstellar Travel
By: Dr. Keith Wiley
Published: September 23, 2011
While most people focus on the engine, we better think about the brain of a star probe, too.