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Louis Friedman Says Humans Will Never Venture Beyond Mars (scientificamerican.com)
MarkWhittington writes: Dr. Louis Friedman, one of the co-founders of the Planetary Society, is coming out with a new book, "Human Spaceflight: From Mars to the Stars," an excerpt of which was published in Scientific America. Friedman revives and revises a version of the humans vs. robots controversy that has roiled through aerospace circles for decades. Unlike previous advocates of restricting space travel to robots, such as Robert Park and the late James Van Allen, Friedman admits that humans are going to Mars to settle. But there, human space travel will end. Only robots will ever venture further.
It was received wisdom that flying, let alone landing on the moon, was beyond the engineering capabilities of humanity. The most significant reason why scientists' input into the public sphere should be treated as no more than "probably good advice" is the complete lack of a historic perspective and humility so many seem to have. You'd think the number of times the consensus is one thing and one or two rebels make fools of the consensus would be a cause for open-mindedness in the current generation, but you'd be wrong.
The problem is experts tell you what can't be done NOW. They rarely speculate about what might be possible in the future.
I'm not sure why. It does not seem implausible that a crew for a generational ship could be found.
Including self-destruction
Yep. In fact, self-destruction is more likely than us spreading out beyond Mars. Of course we might travel beyond Mars, but at this point I think that we have enough scientific reason to think that colonizing beyond Mars is so unlikely as to be functionally impossible. There are a host of reasons, but to name a few: (1) faster-than-light travel is theoretically impossible (and only possible in mere speculations), (2) near-FTL travel is a mere dream, (3) the human body can hardly take long-term space travel as it is, (4) we allow ourselves to be guided more by politics and profit than by any "higher" goals, so we will never unite our resources on such a project unless it promises major returns in these areas, etc.
We can (and probably should) always fantasize about new technologies, etc., but there are real limits to our abilities and we do run up against them. Of course through genetic engineering, etc., we could fashion a new kind of human that might be better equipped for the challenges of interstellar colonization, but given the potential limitations of life (we can only dream and watch Star Trek to imagine a biological being that is really adapted for the conditions of space), it is at least unlikely enough that we will colonize farther than Mars that I think the word "never" is not far-fetched.
Incipiamus, fratres, servire Domino Deo, quia hucusque vix vel parum in nullo profecimus.
The book Aurora, by Kim Stanley Robinson, makes an interesting argument for why generational ships are perhaps not so great. In a nutshell, it's fine if you want to choose that life - risk and claustrophobia - for yourself and maybe some of your friends.
But can you really make that choice for your children and grandchildren, unto a dozen generations? For better or worse, it's their lives that you're playing dice with: catastrophic environment failure, unpredictable social evolution, who knows. When you're in a generation ship, there's no escape, after all.
A paradigm doesn't have to make people scrap their core textbooks (such as the big daddy example of the acceptance of continental drift theory). Seemingly small developments can produce enormous change. The creation of vulanised rubber, so allowing pneumatic tyres, saw a paradigm shift in road transport, but it can also be seen as just an incremental shift in technology. The development of the route to the moon through enormous rockets and very complex orbital rendezvous became redundant after the LEM plan was adopted.
This is also an example of where there was significant agreement between The Experts that a similarly qualified, but not so senior, expert was wrong.
Freeman Dyson gave an interesting talk a couple of years ago, speculating about the next few centuries of exploration and settlement. He envisions colonies in the Kuiper Belt in a couple hundred years, but not much beyond Mars for the next 50 or so. And he anticipates an "island hopping" model of interstellar expansion, similar to the Polynesian settlement of the Pacific. Anyway, it's an interesting talk. (34 min)
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And this is different on earth? You never know what situation you'll find if you have to flee a place. On the contrary, there is evidence that humans can be better at living together despite differences when there is no alternative.
Offspring can always find a reason to blame the parents if something goes wrong.
Besides, if your goal is terraforming, a solar shade doesn't really cut it - you have to get rid of the huge amounts of CO2. My favorite proposal is a solar chimney - basically a giant funnel-shaped greenhouse floating on Venus. The gas accelerates faster and faster the further it rises into the funnel - and due to the megascale-engineering scale, suffers (proportionally) almost no slowdown from the surface drag. Hence, if large enough, velocities of tens of thousands of meters per second could be reached - well beyond escape velocity and even potentially to intercept trajectories with other worlds (giving them Venus's CO2 for their own terraforming needs). A vortex-inducing funnel could centrifuge out the gases so that by shaping the exit nozzle one could preferably lose heavy gases and keep the lighter ones. The structure - being of insignificant mass compared to the mass of the rising gases - could be self-lofted, like a parachute in an updraft. Actuated vents could provide thrust for stationkeeping and aim. One could even build other such funnels elsewhere, such as on Jupiter to export hydrogen back to Venus for the Bosch reaction.
Still doesn't help with rotation, though.
Another possibility which would be very difficult, but not require megascale engineering, would be breeding bacteria to sequester carbon. This has sometimes been dismissed due to a lack of nutrients in the Venusian atmosphere, but this may be a bit shortsighted. In addition to carbon, oxygen, nitrogen, water, and sulfur, there's small amounts of chlorine (in the form of hydrochloric acid) and phosphorus (in the form of phosphoric acid) in the cloudtops. Other nutrients can prove trickier to get, but there is a potential source: the Venera probes found what appears to be volcanic ash in the atmosphere, identifying for example the signature of iron during their descent.
While some of what they would need to function would be quite rare, technically everything that life needs appears likely to be able to be found in venus's clouds at temperatures that life can survive in. So perhaps one could engineer free-drifting longlived microorganisms that would use cloud droplets around ash condensation nuclei to breed - perhaps some sort of sporulating species.
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