Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Mon, 1 Jul 91 04:50:43 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 1 Jul 91 04:50:35 -0400 (EDT) Subject: SPACE Digest V13 #761 SPACE Digest Volume 13 : Issue 761 Today's Topics: Re: Launch failure today What is the Cheapest Import from Outer Space? Re: Mining El Dorado Re: Space heros? Re: Mars "face" The USF. Re: Fred's Operatic Death Re: Mars "face" Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 19 Jun 91 04:57:45 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!bonnie.concordia.ca!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: Re: Launch failure today In article <1991Jun19.024459.15721@helios.physics.utoronto.ca> neufeld@aurora.physics.utoronto.ca (Christopher Neufeld) writes: > What was this launch? I wasn't aware of any prospectors due up in the >next little while. While we're at it, what was the launch vehicle? It >sure didn't look like a Pegasus. It was a suborbital microgravity launch, being done by OSC's Space Data subsidiary. "Prospector" is the name of the launcher, which I think is yet another of those slap-some-existing-solids-together things. -- "We're thinking about upgrading from | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 to SunOS 3.5." | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 17 Jun 91 10:18:05 GMT From: tristan!loren@lll-winken.llnl.gov (Loren Petrich) Subject: What is the Cheapest Import from Outer Space? 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 ------------------------------ Date: 17 Jun 91 14:41:37 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucbvax.Berkeley.EDU (James Davis Nicoll) Subject: Re: Mining El Dorado In article <1991Jun17.052228.8112@sequent.com> szabo@sequent.com writes: > >Some issues here: > >* We can't use Earth gravity assist or aerobraking for such a large > asteroid and unpredictable propulsion scheme. Therefore, the delta-v > is likely to be quite large (several km/s). > >* The energy required to achieve that delta-v would likely disrupt or > vaporize the asteroid. For example, to achieve 4,000 m/s the power > output is (1e10 kg)(4,000 m/s)^2/(.01 s) = 1.6e19 watts assuming a > propogation time of .01 second. Of course, we could do multiple > explosions, but hundreds to thousands of small nuclear warheads starts > to get expensive. This is probably a stupid question, but is the change in kinetic energy (and a power rate based on a time value that appears to me to be arbitrary, unless I missed something) a particularly useful number to look at? Hmmm. That is phrased poorly. Maybe an example: Take a 1 kilo object and change its velocity by 1000 m/s. That's a change in Ek of 0.5(1 kg)(1000 m/s)**2 or 5 x 10**5 Joules. Now, let's assume we're using a rocket to cause the delta vee which has an Isp of 400. Mass ratio will be something like: M1/M0 = e**delta vee/exhaust velocity = e**(1000 m/s)/(4000 m/s) = 1.28 If M0 = 1 kg, then M1 = 1.28 kg, so we have to throw .28 kg to get our delta vee. Ek = .5(.28)(4000)**2 = 2.24x10**6 Joules. To power the system we're using, we have to come up with 2.24x10**6 J, but the change in Ek in the object is only 5x10**5 J, a bit more than a fifth of the energy we actually use. The ratio between the delta Ek of the object and the energy we actually use for a given propulsion system goes up as Isp increases, of course. In your example up above, while the delta Ek is 1.6x10**17 J, the actual energy we'd need would be higher (How much higher depends on the Isp of the system we use). As an aside 1.6x1017 J is about the amount of energy we could produce using all the the world's current off- the-shelf supply of nuclear explosives (Actually, it's two or three times as much), so we'll need to build more nuclear explosives to move the above rock, perhaps much more, depending on hw we use them. Anyone out there have an idea how much nukes cost per megatonne? If there's some painfully obvious reason you used the delta Ek and the .01 second values you did, take it as written I pound my head shapeless in contrition. James Nicoll ------------------------------ Date: 17 Jun 91 18:30:07 GMT From: mintaka!think.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!helios!sheaf@bloom-beacon.mit.edu (Sheaf) Subject: Re: Space heros? In article <1991Jun8.070607.28401@sequent.com> szabo@sequent.com writes: >In article <".7-Jun-91.11:13:48.EDT".*.Eric_Florack.Wbst311@Xerox.com> Eric_Florack.Wbst311@XEROX.COM writes: >> >>To obtain the >>public's support, and therefore, an easier time at obtaining public funding, >>at least a certain degree of the space exploration should be manned... > >This is total BS. The civilian space program was originally motivated >by the automated IGY satellites, the first being Sputnik which shocked >the U.S. into funding spaceflight. The correlation between astronaut >flights and NASA funding is negative. NASA funding started to drop in >1966 after Gemini swung into full gear, and dropped most precipitously >during the Apollo flights which the American public increasingly opposed. >Polls have always showed roughly equal public support for "unmanned" >and "manned" endeavors, even when stated with that falsely dichotomous >terminology. The myth that astronauts somehow motivate space funding is >the last refuge for those who can't find any other rationale for the >wasteful astronaut toys the NASA leadership (astronauts) are pushing. > I agree 100%, Nick, I think the general public (at least from waht I could see), was more taken with the VOYAGER encounters than anything else we've done since Apollo 11. The Viking landings as well. At least to the non-scientific people that I know, the results of these missions are better known than anything thats been done with the shuttle. In fact, if the Challenger hadn't exploded, most of them wouldn't give the shuttle program a second thought now. I think too many of us think that the public is awed by technologies like the shuttle that seem to bring science fiction closer to reality, but its been my experience that this isn't really true. If anything, they now take it for granted. I'd say part of the shock of the Challenger was that so many people no longer felt that it was still an experimental and risky technology. But the stunning images sent back from the outer solar system, that was something that no too many of them (or us) could have imagined. The spirit of discovery isn't just for scientists, and the general public is going to see more obvious payoffs from these types of missions than from a space station where the payoffs will be much less accessable to non-scientists. Besides, the pricetag on unmanned exploration is an awful lot easier for all of us to take. S. Sheaffer - sheaf@helios.phyast.pitt.edu ------------------------------ Date: 17 Jun 91 19:15:26 GMT From: agate!lima.berkeley.edu!bks@ucbvax.Berkeley.EDU (Bradley K. Sherman) Subject: Re: Mars "face" I wonder if there are Martians poring over images of the Grand Tetons trying to ascertain the meaning of this message from the Earthlings. ---------------------- Brad Sherman (bks@alfa.berkeley.edu) ------------------------------ Date: Tue, 18 Jun 1991 16:50 EDT From: Is it Friday yet? Subject: The USF. X-Organization: Southeastern Massachusetts University, North Dartmouth, MA, USA Comments: A VAX cluster with VMS 5.3-1, PMDF V3.2-19, JNET V3.5 & UCX V1.3A Rather than clog up sci.space with more long posts about your charter, why not post some facts that many of us who might be potentially interested in joining your organization would need to know first: 1) What is the current membership? What is the composition of this membership? You claim to be an international organization, how many members do you have abroad? 2) What governments currently recognize your organization? Any international authority you might have is going to have to be acknowledged by the governments involved, especially if your organization intends to be militarily neutral. 3) What resources does your organization currently possess? You seem to have some very grandois plans, do you have the means to carry them out? 4) What activities has your organization already begun? Do you have any accomplishments to show other than a wordy charter? If you have concrete answers to these questions, I would be very interested in hearing them. If not, I think you are just wasting bandwidth by repeatedly posting your charter without actually contributing anything to the newsgroup. --Matthew Setzer Undergrad Math/CIS Major Southeastern Mass Univ acsmcs@smucs1.semassu.edu ------------------------------ Date: 17 Jun 91 05:53:44 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!mintaka!ogicse!sequent!muncher.sequent.com!szabo@ucbvax.Berkeley.EDU Subject: Re: Fred's Operatic Death In article <1991Jun14.083756.1@vf.jsc.nasa.gov> kent@vf.jsc.nasa.gov writes: >The kind of arrogant attitude you project with statements like "astronaut >groupies" and implying that pro-manned space people call finaciers "Bean >counters" makes me discount your arguments. "Astronaut groupie" is a description based on observations of people flocking out to Edwards to watch the Shuttle land, getting astronaut's autographs, and worshipping deceased astronauts as martyrs. This is very similar to the behavior of a rock band groupie. I don't see any reason to make my language less descriptive of reality. Some of these people do in fact call the politicians who fund their programs, and people who keep track of those funds, "bean counters". _That_ is arrogance. There have been at least 3 examples of this perjorative in this newsgroup during the last year. I encountered it repeatedly as a member of NSS. Many do in fact discount scientist's opinions while claiming that their projects are for "science". That is hypocrisy. The fact that your employer, JSC, gets its revenues via the IRS for astronaut projects makes me discount your "pro-manned" statements. Quit wasting my tax money making self-serving posts to the net. Quit wasting my money on engineer-welfare projects like Fred. Get a real job. -- Nick Szabo szabo@sequent.com Embrace Change... Keep the Values... Hold Dear the Laughter... These views are my own, and do not represent any organization. ------------------------------ Date: 17 Jun 91 12:48:34 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!ptimtc!nntp-server.caltech.edu!sol1.gps.caltech.edu!CARL@ucbvax.Berkeley.EDU (Carl J Lydick) Subject: Re: Mars "face" In article <1528@gtx.com>, al@gtx.com (Alan Filipski) writes: >Instead of a bunch of amateur interpretations of this picture, it would >be interesting to get a professional's opinion. There are people who >spend their entire careers interpreting satellite and aerial recon >photos. Most of them work for the government, but many are retired. >Have any of these people given an opinion on the photos? I've talked to two of them. I won't try to fit a transcription of about 15 minutes of laughter into this message. At the end of the laughter, the comments were something like "I shouldn't laugh. There are some people who actually take this SERIOUSLY". -------------------------------------------------------------------------------- Carl J Lydick | INTERnet: CARL@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL ------------------------------ End of SPACE Digest V13 #761 *******************