loren@tristan.llnl.gov (Loren Petrich) (06/17/91)
I was discussing the question of suitable space projects not too long ago, and I was told that a study had revealed that the cheapest import from outer space was information(!). For instance, it is relatively easy to send back, since one can encode radio waves with it; simply compare trying to send back a spacecraft module with some physical object(s) on board. And consider that one wants to keep weight down. It is significant that the most successful space applications so far have involved sending back information. These fall into three main categories: surveillance, communication, and navigation. Into surveillance falls both optical and radar imaging; electronic intelligence is a cross between the first two categories; and the information for navigation is position and information derived from a signal's travel time. Nearly all of the commercial schemes for new satellite systems fall into one of these categories. I note that all spacecraft sent beyond the Moon have only returned information; sample returns are still in the proposal stage. If one wishes to return physical objects, then it is appropriate to have ones with high value per unit mass, to get around launch costs. This has been the philosophy of most space manufacturing schemes so far, which have tried to utilize microgravity to make quality materials that are difficult to manufacture under Earth-normal gravity. These include standard-sized beads, crystals, and certain biologicals (more properly, their purification). Most proposed schemes follow this strategy also, involving utilizing either microgravity, high vacuum, or both, to produce materials with high value per unit cost. It is evident here that sending people up into space is something of a loser. One needs to send up the astronaut, to keep him/her alive during the flight, and to return him/her safely. All of these require LOTS of hardware. Reusing some of this hardware would be valuable; that is the basic motivation behind the Shuttle, and that has been the philosophy of the space stations that have been sent up so far (no need to send up a new one each time). The Shuttle's disappointing performance indicates that outer-space technology may not be quite ready for ready access to space by human crews. However, we excel at tasks of perception and manipulation that are still very difficult to program into computers, and remote-controlled systems can sometimes get awkward, so there might be some use for astronauts after all. I think that it is worth comparing to the early voyages of exploration some centuries back, as I had done in a previous article; the main articles of trade then, like items brought back from outer space now, were items with high value per unit mass, such as precious metals and stones, spices (pepper was one hot commodity), and silk. One could load a very high value of these aboard one's ship before it starts to sink, as compared to (say) firewood. So weight costs were important for those voyages, also. Unlike the present situation, however, information import was only a secondary interest; the main information that interested most early Spanish New World explorers, for example, was the location of gold. When one considers what kind of crew, the automated option, which now scores highly, would not be developed for centuries. I'm not sure of accomodations aboard the Chinese ships, which were rather large, but the European ships were small and cramped. Even the captain didn't get too much room by present-day standards. Thus, the European efforts came close in spirit to unmanned spacecraft, which can be made VERY light. In my previous article, I had compared Chinese and early European explorations with regard to how they were supported, and compared them to current space projects. Big prestige projects with central supporters are impressive, but VERY vulnerable to political whim and charges of benefiting some select group of fat cats. Smaller scale projects with less centralized support have much greater longevity, and are less dependent on any individual success or failure. A final comment about depictions of space travel. Before it happened, just about every depiction of space travel featured a human (or some equivalent sentient) crew controlling the craft. I often got the picture of a spacecraft as a glorified ship or airplane, controlled by some human pilot. Automated (remote-controlled and/or preprogrammed) spacecraft were nonexistent, at least in the sample of early science fiction I have read. Any counterexamples would be welcome. The closest I can think of was Arthur C. Clarke's proposal for radio relays in synchronous orbit. I think a good parallel is with robots and computers. Robots, with essentially human perceptual and motor skills, have been a staple of science fiction and fantasy for centuries. There were no anticipations of computers, which may be interpreted as disembodied brains. However, science-fiction writers had no trouble writing them into their stories when they started showing up in real life. Interestingly, the "mental" abilities of computers are the opposite of ours; they excel in minutely detailed bookkeeping, while failing miserably in simple perceptual and motor tasks. AI systems could succeed on college-level IQ tests, while failing on kindergarten-level IQ tests. This is another thing that was unpredicted. That is one of the reasons for interest in Neural Nets and related architectures, which sacrifice the apparent sophistication of rule-based inference for demonstrable success in pattern recognition. On space travel itself, planets were usually pictured as the primary destinations, with spacecraft taking off from and landing on them. Spacecraft confined to outer space (no landings possible), space stations and free-flying habitats were rarely depicted before recent decades (counterexamples welcome here, also). Here again, the present time features a lot of reversals, with space-confined spacecraft being nearly universal and the only extended stays by people outside of Earth being in space stations (something like miniature free-flying habitats). The only human visits to another large Solar System object have been to the Moon, and there, only briefly. Plans for large-scale human habitation still seem focused on living on the surfaces of planets and large satellites, though free-flying habitats have attracted a lot of interest. So one should expect the future to have lots of surprises, if nothing else. Some analogies form the past will work very well, while others will not. $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Loren Petrich, the Master Blaster: loren@sunlight.llnl.gov Since this nodename is not widely known, you may have to try: loren%sunlight.llnl.gov@star.stanford.edu
3001crad@ucsbuxa.ucsb.edu (Charles Frank Radley) (06/18/91)
You are the first person from llnl I have seen post here. Do you have any news about Dr Wood's "Great Exploration" ?