ucbesvax.turner@ucbcad.UUCP (01/12/84)
#N:ucbesvax:8700010:000:8352 ucbesvax!turner Jan 5 02:14:00 1984 This month's issue of Technology Review has a proposal for a manned Mars base. Some of its conclusions (probably familiar to most of you): - the bulk of the materiel should be freighted by unmanned long-haul propulsion systems like solar-sails and ion drive, in "small" batches (measured in hundred of tons); there will be dozens of these; - crew transport will require higher velocities (liquid hydrogen/oxygen engines are mentioned) because of the dangers of longer travel times; radiation and gravity- deficiency syndromes are mentioned; braking fuel can be conserved by skimming the atmosphere; a solar storm shelter will be needed; - a crew of seven members of both sexes is optimal; an odd number, to break ties in voting (?!), and more than five, for social variety; both sexes probably because this also provides more variety; all results derive from psychological studies; being past child-bearing age will be a consideration in crew-choice, in view of the radiation hazards; - forward basing on Phobos/Deimos, for a months-long survey (with ground-based rovers) prior to actual basing; - once on the surface, it might be possible to use gliders for long-range surface missions; - on the trips over and back, complete recycling is infeasible; all food for the journey must be taken along; - plants can grow at low atmospheric pressure--greenhouse agriculture is possible in inflated surface bubbles; - fuel tanks can be reused as surface housing, buried in Martian soil for insulation and radiation-shielding; - equatorial sites are preferred over polar sites, even if vital resources (water, oxygen, etc.) are more easily extracted at polar zones--it seems that Martian winters are not to be trifled with; - no problems with using Martian resources; most necessities (oxygen, inert buffer gases for breathing, water, desalinated soil for growing, etc.) can be extracted in more than one way; - "complex AI techniques" are disparaged in the context of unmanned surface rovers; - projected cost: around 2/3 of Apollo, with much lower annual outlay by comparison; expected year of basing: 2000 AD. While not an expert, I still feel the need to question some of their conclusions. Some of these objections are detailed below. STYLE OF TRANSPORTATION I fully approve of long-haul techniques, if they can be made workable-- they favor economies of scale (both in transport and in production of transport); there has been, to my mind, far too much "get it done somehow, drop it later" in the U.S. space programs. However, I don't agree with the conclusion that long-haul *manned* transport is infeasible--I suspect that rocketry is being pushed rather more for its usual drama, even though the manned vehicle would certainly be launched from orbit rather than from the surface. Would an American public wait 18 months longer for the trip to complete? The question is absurd--the proposal is *already* asking them to wait for 18 years. The matter of safety is compelling, but not convincing: unless the trajectories for either the trip or the return voyage involve close solar orbits, why bother with speed? Why not send more people by sail, shielded by cargo, perhaps in smaller batches. Intervehicle shuttles could be used between storms for social exchange, emergencies, etc. (Trips from one group to the next might take a while at maximum separation. "Captain, can I have the car for a few weeks?") Occasional social isolation and social separation might go a long way toward providing the variety that psychologists find so important. Separate, long-haul manned vehicles might actually improve overall safety, since if one group is lost through some accident, the remaining groups can continue. Not to mention the messy, scary-sounding business of coming out of a month's long high-speed trajectory to brake against an atmosphere. (I realize that I should have more faith in computers, but . . . ) Consider the matter of cost as well--two vehicle development programs will be more expensive than one, and the rocket-powered vehicle would be another expensive one-shot deal. RECYCLING DURING TRIP There are two basic approaches to total recycling: contained ecology and chemical processing. (Even the contained ecology approach will involve some chemical processing, of course.) Chemical processing is difficult; it would certainly require much heat, with dead-mass costs for radiating the excess. Any breakdown of processing equipment could be fatal. Derived foodstuffs would probably be horribly unexciting. Contained ecology is tricky. Don't get the idea that they'll be taking tons of dirt, I'm not advocating that. But I think that a decade of near-orbit experimentation could produce a system that is compact, maintainable for years, and with very low energy requirements. Almost certainly, it would be more massive than the food-supplies for an 18-month liquid-fueled round-trip. But again, I object to that style, and would in any case prefer to see contained ecology techniques, since development of these can start now (on Earth), and will have long- term benefits, with much spin-off potential. Genetic engineering will find a place here, I think. The research cost could be quite low. PSYCHOSOCIAL DYNAMICS The article points out that Russian cosmonauts have received better training than Americans in dealing with the psychological stresses of long orbital stints. (Nevertheless, the tedium is thought to be extreme--possibly the biggest single problem in a six-month mission.) We are just now going beyond the test-pilot psychological profile-- people who can handle long periods of little excitement are quite different from those who are best fit to sporadic adrenaline rushes. In view of what I have laid out above, perhaps a recent Nobel Laureate geneticist represents (but for her very advanced age) the ideal Mars mission crew-member: patient, methodical, reclusive, impossible to ruffle, and devoted to the natural sciences. (And the ideal candidate's reaction to being selected? "Oh, dear--photographers, again.") The matter of sexual balance is fraught with questions that are irrelevant to mission objectives. The rationale is that there will be sex--so there must be men and women. (But with an odd man or women out?) I favor a sexual balance for other reasons than this, but an all-woman or all-man crew doesn't seem out of the question. Maybe there will still be sex--so go flame in net.flame if this irks you. I have seen fewer problems with jealousy in homosexual relationships than in heterosexual ones. Given the way attitudes are changing now, by 2000, the moral questions might be considered totally irrelevant. I applaud the idea of using older people, though not so much for the reasons given. There is even a PR angle, here (where I have been so contemptuous of that in comments above): by 2000, we will be a nation of older people. Given the underlying theme of the mission, as implied by the article, choosing older people makes a lot of sense-- that, as a nation historically and demographically middle-aged, we still have what it takes. (How old will *you* be in the year 2000?) CONCLUDING NOTES I think the projected cost is an overestimate. I think the safety- measures rationale looks dumb in view of ideas like using a glider in a thin atmosphere over boulder-strewn, craggy terrain. I think the "complex AI techniques" bit is more rationalization--a maximum speed of 1 mph would probably take care of most reaction-time problems. Rapprochment with the Russians would get us their walker-technology. On the favorable side, the low-pressure bubble-greenhouses sound like fun. Perhaps they could be layered to provide staging between pressure zones, a gradation of Martian-thin-to-human-breathable atmospheres, thus providing a buffer against sudden pressure loss in the main modules. If the sails are nonporous (see an earlier note of mine as to why they might not be), and the reflective coating could be stripped, they could be laminated to make bubble-tissue, yielding the prospect of very large, multicellular atmosphere containers, arranged for fail-safe protection against sandstorm damage. --- Michael Turner (ucbvax!ucbesvax.turner)