MarsBlog.net

Rand Simberg posts some reasons why space elevators might not be such a good idea after all. Even as the technology is becoming available to make them possible.

Anyone who has read Red Mars can readily imagine the consequences of a terrorist attack on a fixed-base space elevator.

So, how do we produce polymers from water and carbon dioxide? By turning them into synthesis gas, a mixture of carbon monoxide and hydrogen.

Given a supply of water (and of course energy) one can use processes similar to those used to produce return-voyage propellants in the Mars Direct architecture — namely, the reverse water gas shift. The water is split via electrolysis to obtain hydrogen, some of which is then reacted with atmospheric carbon dioxide via RWGS to produce carbon monoxide and water. The water is returned to the cycle and the freed oxygen can be used for life support, but the carbon monoxide is mixed with the remaining hydrogen to produce synthesis gas, which then feeds into the production of polymer materials (via free radical polymerization, Ziegler-Natta polymerization, metallocene catalysis polymerization, etc.).

The beauty of martian plastics is that they can be produced in part with equipment which is already present on the surface for other purposes, using processes which are well-known from decades of terrestrial industrial experience.

SpaceDaily has an article on the latest theories concerning the formation and composition of the Martian polar caps.

It’s fortunate that much of Mars’ available water is locked up in the northern hemisphere. The topography in that region is generally more gentle than in in the southern hemisphere (hence our tendency to land probes and rovers there), and will for that reason be the likely landing site for manned expeditions and early settlements. Since a local supply of water is of critical importance to settlement of the planet, it’s a good thing that it will be available fairly close to these potential landing zones.

Purdue To Create Life-Supporting Ecosystem In Space

This is all very interesting.

But.

It strikes me that these elaborate “closed system” approaches, at least for settlement of the Martian surface, are taking things much further than what is required. Is it really necessary to put in all the hard work and perform all the fine-tuning such complex, artificial systems would require? Are settlers on Mars really going to have the time it will take to continually monitor and adjust and tweak and troubleshoot such systems?

There is clearly a need for some form of waste recycling — whether it is sewage, “grey water”, plant waste, what have you. And there is clearly a need to produce (as opposed to continually transport) food for the settlement. And there is clearly a need to continually freshen the air. However, Mars is not interplanetary space — there are plentiful resources available on the surface. Do recycling and food and air production systems really have to be closed loop systems, when the materials to replace the losses are more-or-less readily available?

I don’t believe so. While these sorts of studies are useful, in terms of pushing the technologies involved to higher levels of efficiency, there is always an element of Zeno’s paradox involved. Do we really want to wait until that last n% efficiency in the closed-loop system is achieved? Or will we be satisfied with something less: merely “high-efficiency” systems?

Another point which seems misguided to me is the reliance on existing crops. The closed-loop proponents never seem to take advantage of genetic modification to enhance the efficiency of the organisms they plan to use in their reactors and such. Nor do they seem to understand that manipulation of certain plant traits could offset much of the potential difficulty with using Martian soil as-is. Furthermore, this approach could expand with the settlement (just add another greenhouse), whereas the “brittle”, expensive, highly-artificial, and imported closed-loop systems would inevitably turn out to be limiting factors to the settlement’s growth.

Perhaps including such possibilities in their studies is beyond what their funding will allow, but if so, it is a line of research one would expect to see pursued elsewhere, and referred to as a potential future enhancement. Instead — silence.

Which is a shame, really. Modified plants which perform these vital functions while requiring little human attention — even at the cost of some overall efficiency — would be far more beneficial to the settlers than the elegant but more-trouble-than-it’s-worth closed-loop approach. We are not going to Mars to build “Biospheres” for the sake of building “Biospheres”, after all — we are going there to settle and explore. While making for interesting and possibly useful intellectual exercises, closed-loop research must not be regarded as providing us with enabling technology for Mars settlement, especially when there are simpler and cheaper alternatives.

Popular Science suggests seven things that NASA can do to reinvigorate space exploration.

It’s also Recommendation #1 (page 3), namely to officially designate Mars exploration as a long-term goal for NASA.

NASA’s Mars plans won’t be taken seriously until the agency lays out the logical progression of steps that must be taken and attaches realistic dates to them.

Once NASA establishes that its overarching goal is to reach Mars?say, within a generation?then other pieces of the space program will begin to fall into place. Research on the space station will focus on learning the biological effects of long-duration space travel. Unmanned probes will lay the groundwork for a future manned landing. And engineers will have a likely destination for the next-generation space vehicle. A commitment to Mars will refocus the agency and give it a sense of mission.

Which is what we have been saying all along.

Recommendation #3 (page 5) reiterates the Cato position on privatizing space activity between LEO and Luna.

“NASA is an exploration agency, not a construction company or a landlord,” says Tumlinson.

It’s a great approach towards the follow-on Mars activity I mentioned earlier — transition local activities from NASA to private concerns while the agency is preparing for Mars, so that there will be a thriving space-based industry ready to step in at the right moment. Space tourism has great potential in this regard, and as noted, NASA needs to stop throwing up roadblocks to it and instead roll out the red carpet — whether that means allowing limited ISS access, permitting a privately owned and operated “hotel” module to be added to ISS, or just getting out of the way of fully-private space launch and space tourism ventures.

Recommendation #6 (page 8) concludes with an observation that warms the heart:

But though a robot can send back interesting data, it can’t make sophisticated interpretations. Unmanned missions, while important precursors to human exploration, are a poor substitute for it.

The seventh recommendation (page 9) makes the point that a lot of us have made: settlement of other bodies in the solar system is an important insurance policy against all manner of planet-wide calamities.

It’s a good article, well worth a read.