Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from holmes.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Mon, 17 Apr 89 00:18:43 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 17 Apr 89 00:18:34 -0400 (EDT) Subject: SPACE Digest V9 #372 SPACE Digest Volume 9 : Issue 372 Today's Topics: Rail-Guns and Asteroids Re: Rail-Guns and Asteroids Acting NASA Administrator to resign (Forwarded) Re: long ago and far away Re: Soviet shutdown of manned space program Re: Soviet Mir space station in trouble Re: Thermal Pollution (was: Fusion: Expendible resources) thermal pollution (was: Fusion: Expendible resources) Re: UK astronaut to be launched by Soviets Re: U.S. vs Soviets (was Re: Alien contact) Venus radar mappers ---------------------------------------------------------------------- Date: Wed, 12 Apr 89 16:02 EST From: ELIOT@cs.umass.EDU Subject: Rail-Guns and Asteroids Would it be reasonable to use Rail-Guns in mining an asteroid. I am thinking that a large pellet of metal could be fired from an asteroid based mining unit back to earth or the moon. The pellet could either be tracked and caught when it gets near the earth, or it could be fired so it hits the moon, and then retrieved from the (new) lunar crater. The shape and composition of a pellet would not be important. Presumably, it should be small enough so that it could not survive reentry on earth. (Decreases liability insurance.) The rail gun could be operated with fusion or solar generated electricity. The advantage of this scheme is that a mining operation could return a continuous supply of raw materials, without requiring complex rockets to return it. The only rockets/chemical fuel needed would be to transport the mining equipment and miners to the site, and return the miners. Could this scheme be used in reverse? Could water, food, fuel and other supplies be sent to mars or an asteroid mining site using rail guns? Chris Eliot Umass Amherst ------------------------------ Date: 14 Apr 89 03:15:39 GMT From: blake!wiml@beaver.cs.washington.edu (William Lewis) Subject: Re: Rail-Guns and Asteroids In article <8904122007.AA10396@crash.cs.umass.edu> ELIOT@cs.umass.edu writes: > Would it be reasonable to use Rail-Guns in mining an asteroid. > I am thinking that a large pellet of metal could be fired from an > asteroid based mining unit back to earth or the moon. ... The problem is that any pellet massive enough to send to Earth (or the moon or...) would be massive enough to make the railgun recoil quite a bit. Either you can make the railgun very massive (by using the unused bits of asteroid as a momentum sink), or try to make the recoil push the railgun in a useful direction (such as the next asteroid down the line.) The problem with the latter is that Earth would probably not always be the best direction to throw something to get said something to the asteroid belt. > ... The pellet > could either be tracked and caught when it gets near the earth, > or it could be fired so it hits the moon, and then retrieved from > the (new) lunar crater. ... Of course, you'd lose quite a bit of material blasted away by the impact. Very impracticl / inefficient. > .... The shape and composition of a pellet would > not be important. ... Huh? The composition not important? Why do you go to all this trouble to fire garbage pellets at Earth? I'd at least want the pellets to be something I can use! > .... Presumably, it should be small enough so that > it could not survive reentry on earth. (Decreases liability > insurance.) [stuff about reuseability & electrical-powered-ness of railguns] Why railguns? Why not magnetic linear accelerators? Or giant electrically powered catapults (the miners can grow their hair long, you see, and...)? > rockets to return it. The only rockets/chemical fuel needed would > be to transport the mining equipment and miners to the site, and > return the miners. Why use miners at all? Strikes me this could be more easily automated... which makes the whole package cheaper, lighter, etc. ~~~~~~~~.sigs in spaaaaaace!~~~~~~~~~ ------------------------------ Date: 12 Apr 89 23:14:25 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Acting NASA Administrator to resign (Forwarded) David W. Garrett Headquarters, Washington, D.C. RELEASE: 89-49 ACTING NASA ADMINISTRATOR TO RESIGN Dale D. Myers, the acting NASA administrator, has announced his plans to resign effective May 13, 1989. Myers, acting administrator since April 8, 1989, served as the NASA deputy administrator from Oct. 6, 1986, when he was called back to NASA by President Reagan. During this tenure, Myers was instrumental in guiding NASA through the period of recovery following the Challenger accident of Jan. 28, 1986. Some major accomplishments during this period were the substantial redesign of the Space Shuttle system including the solid rocket motor and the subsequent return to manned space flight in September 1988; reorganizing the Space Shuttle management structure and centralizing the Space Station management; and the reinstitution of a mixed fleet strategy using commercial expendable launch vehicles in addition to the Shuttle. In his letter of resignation to President Bush, Myers wrote, "I am most grateful for the opportunity to be of service to the Nation. I will continue to support you and this administration to the best of my ability in the years to come." Myers has served two tours at NASA Headquarters -- his present position and earlier as the associate administrator for manned space flight from 1970 to 1974. He also served as under secretary, U.S. Department of Energy from 1977 to 1979. From 1974 to 1977, he was vice-president, Rockwell International, and president, North American Aircraft, El Segundo, Calif. Born on Jan. 8, 1922 in Kansas City, Mo., Myers is a graduate of the University of Washington, Seattle, with a B.S. in aeronautical engineering. He received an honorary doctorate from Whitworth College, Spokane, Wash., and distinguished service medals from both NASA and the Energy Department. He was elected to the National Academy of Engineering in 1974. Myers is married to the former Marjorie Williams of Seattle and they are the parents of two daughters. ------------------------------ Date: 13 Apr 89 19:25:22 GMT From: att!homxb!homxc!brt@ucbvax.Berkeley.EDU (B.REYTBLAT) Subject: Re: long ago and far away Not so long ago, nor as far away: On april 12, 1981, STS-1 lifted off from pad 39-(A or B, Henry?). Ben Reytblat no cute signature no cute disclaimer ------------------------------ Date: 14 Apr 89 04:57:20 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Soviet shutdown of manned space program In article K_MACART@UNHH.BITNET writes: > I just heard that the CCCP is not putting up manned missions for a while >(anyone heard how long?). Maybe all the discussion of how much the sov >governments subsidises things is true. Could be there is a big shakedown in >their equivalent of OMB... Or could be they simply have technical problems on Mir and this is a temporary exigency. Frankly, folks, the only *fact* we have right now is that there will be an interruption in the continuous manning of Mir. I don't think I've ever seen such elaborate pyramids of speculation built on such slender evidence. To make anything deep and significant out of this, you basically need to assume that the Soviet space program is run in the same chuckleheaded what-shall-we-do-in-space-today fashion as the US space program (and indeed, most programs of any kind that are funded on a year-to-year basis by democratic governments). That's what it takes to justify an abrupt shutdown of a major ongoing program. To date, there is no sign whatever of the Soviets employing this particular form of mismanagement. (They have their own forms, heaven knows, but this isn't one of them.) It would be very suprising to see such a radical change now. It's enough to make one suspect that some of the speculators have private axes to grind. -- Welcome to Mars! Your | Henry Spencer at U of Toronto Zoology passport and visa, comrade? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 13 Apr 89 16:53:08 GMT From: visdc!jiii@uunet.uu.net (John E Van Deusen III) Subject: Re: Soviet Mir space station in trouble I have read speculation that after the failures of Phobos I and II and in consideration of the minimal gains that can be derived from beating the US in a race in which it declines to participate, the Soviets decided that the money spent upon an aggressive manned space program could better be spent on earth. They are simply cutting back. -- John E Van Deusen III, PO Box 9283, Boise, ID 83707, (208) 343-1865 uunet!visdc!jiii ------------------------------ Date: 13 Apr 89 21:40:20 GMT From: haven!aplcen!aplcomm!stda.jhuapl.edu!jwm@purdue.edu (Jim Meritt) Subject: Re: Thermal Pollution (was: Fusion: Expendible resources) In article <33@boston-harbor> kdo@lucid.com writes: }In article <7695@phoenix.Princeton.EDU> tbrakitz@phoenix.Princeton.EDU (Byron Rakitzis) writes: }> }>I think there's a far more important long-term concern which we must }>bring to our attention: thermal pollution. Whereas solar, wind etc. }>power essentialy harness the energy in the environment, fusion would }>place all this "extra" energy previously stored in deuterium nuclei }>into the environment. I would not be surprised if we found ourselves, }>in the long term, having to limit the use of such non-reversible }>processes as deuterium-fusion. } }If you are talking about thermal pollution of the earth as a whole }it's not likely to become a big problem unless we become incredibly }profligate with energy usage. There are many orders of magnitude }between the amount of energy the earth receives from the sun and the }amount that human beings use currently. We can increase our energy }usage quite a bit before heating the earth will be a problem. If we start throwing so much energy around that the waste starts cooking us we'll also have enough on hand to move the planet away from that nastey old unpredictable star heating up the works. Puppetteers: mind sending the specs via Niven? ;-) Disclaimer: "It's mine! All mine!!!" - D. Duck ------------------------------ Date: 14 Apr 89 11:58:48 GMT From: spdcc!eli@bloom-beacon.mit.edu (Steve Elias) Subject: thermal pollution (was: Fusion: Expendible resources) In article <3637@aplcomm.jhuapl.edu> jwm@aplvax.UUCP (Jim Meritt) writes: !In article <33@boston-harbor! kdo@lucid.com writes: !} tbrakitz@phoenix.Princeton.EDU (Byron Rakitzis) writes: !}! !}!I think there's a far more important long-term concern which we must !}!bring to our attention: thermal pollution. Whereas solar, wind etc. !}!power essentialy harness the energy in the environment, fusion would !}!place all this "extra" energy previously stored in deuterium nuclei fusion isn't the only power source that could add to our thermal problems. how about nuclear fission? solar satellites? !}If you are talking about thermal pollution of the earth as a whole !}it's not likely to become a big problem unless we become incredibly !}profligate with energy usage. There are many orders of magnitude !}between the amount of energy the earth receives from the sun and the !}amount that human beings use currently. We can increase our energy !}usage quite a bit before heating the earth will be a problem. we've got about a factor of 100 or 1000 to go before we reach the same power level as that received via solar flux... but our energy usage is growing by 7% a year or so. it won't take too long to reach that factor of 100. (these numbers have been bandied about sci.physics/misc for the last year or so.) !If we start throwing so much energy around that the waste starts cooking !us we'll also have enough on hand to move the planet away from that !nastey old unpredictable star heating up the works. what you really mean is that we'll be off planet by then, spending our heat/energy where it won't toast the earth's environment... right? there are surely more direct thermal dangers than 'waste heat', today. but we shouldn't ignore potential or current environmental problems just because we'll be able to 'escape to space' some day... -- Steve Elias (eli@spdcc.com);(6172399406) "Space is small. The planets are big." -- Heinlein ------------------------------ Date: 14 Apr 89 07:46:48 GMT From: mcvax!hp4nl!esatst!neil@uunet.uu.net (Neil Dixon) Subject: Re: UK astronaut to be launched by Soviets In article <135@ixi.UUCP> clive@ixi.UUCP (Clive) writes: >According to BBC Ceefax news this morning (Thursday), the UK's first >astronaut will be launched by the Soviets in 1991. 1991, Thatcher's next election year. A cheap publicity stunt is obviously more important than any participation in Europe's own (albeit flawed) manned space program. It will be interesting to see how this can be justified, since their is no obvious profit to be made; but then again, there's always the T-Shirts, Commemorative Book, Record, Video, etc :-). Disclaimer: I'm sure nobody in ESA agrees with me. -- Neil Dixon UUCP:...!mcvax!esatst!neil, BITNET: NDIXON@ESTEC Thermal Control & Life Support Division (YC) European Space Research and Technology Centre (ESTEC), Noordwijk, The Netherlands. ------------------------------ Date: 14 Apr 89 14:55:56 GMT From: prism!ccoprmd@gatech.edu (Matthew DeLuca) Subject: Re: U.S. vs Soviets (was Re: Alien contact) In article <1989Apr13.200900.4891@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <7904@pyr.gatech.EDU> ccoprmd@pyr.UUCP (Matthew T. DeLuca) writes: > >What wondrous capabilities is New Mir expected to have that Freedom won't? > > Turn it around: what wondrous capabilities is Freedom expected to have > that Mir doesn't? Yes, it will be bigger... but Skylab was bigger yet > (yes, last I heard Freedom's internal volume will be less than that of > Skylab)... An article on the space station was in the May 1989 issue of Discover that came out yesterday. Showed the latest design for the station: two 40-foot U.S. modules (1 hab, 1 lab), 1 40-foot ESA module (lab), and 1 20-foot Japanese module (lab). Also included is a 20-foot free-flying ESA module for long-term, sensitive experiments. Solar arrays provide 224,000 watts of power. This seems to be a bit more voluminous than a gutted Saturn V third stage, and the power supply will allow us to run fairly energy-intensive projects. Incidentally, you avoided my question: you were going on about the probable superiority of Novy Mir...again, what greater capabilities will it have? > >> [past glories of US planetary missions] > >... What do the Soviets have in the pipeline in this class? > > What does the US have in the pipeline in this class? Mars Observer is > deliberately a rather unambitious mission. Cassini and friends can't > really be said to be in the pipeline yet -- they've been trying to get > in for years. I wouldn't call Mars Ovserver unambitious. From the looks of it, it is a fairly sophisticated mission that will multiply our knowledge of Mars manyfold. We're beyond the days of the numerous, cheap probes whose sole mission was to survive long enough to snap pictures. We have pictures; now the mission is a lot more complex, and you can't have five or ten of them in the planning stage; it's just too expensive. Last I heard, Cassini was entering the pipeline; there was something in an AvWeek article about funding, although I don't remember what issue. It's going to be a while before Cassini goes anywhere, but then again, Saturn's not leaving the system anytime soon, either. -- --------------------------------------------------------------------------------Matthew DeLuca : Georgia Institute of Technology : Certainty is the lot of those who ARPA: ccoprmd@hydra.gatech.edu : do not question. -------------------------------------------------------------------------------- ------------------------------ Date: Fri, 14 Apr 89 14:52:32 EDT From: John Roberts Formerly: National Bureau of Standards Sub-Organization: National Computer and Telecommunications Laboratory Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Venus radar mappers >From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@csd4.milw.wisc.edu (Henry Spencer) >Subject: Re: alien contact >In article <7810@pyr.gatech.EDU> ccoprmd@pyr.UUCP (Matthew T. DeLuca) writes: >>... Assuming nothing goes wrong (fingers crossed), we'll be sending >>new probes out to Venus, to get the highest quality maps of that planet ever, >Do remember that the highest-resolution maps of Venus existing right now >came from Soviet missions. This is another catchup mission. My understanding of the situation is that the best existing radar map of *most* of the planet was produced by a US probe. Soviet probes then provided a higher resolution map, but only of a small fraction of the surface, around 25%. Now another US probe is supposed to produce a map with still higher resolution, and again of nearly all the surface. It seems to me that this is not a matter of "catching up", but of two separate programs with different agendas, which have been working with one another in a cooperative manner. It often appears that there is a tacit understanding between the planetary science programs of the US and the USSR which tends to limit duplication of effort. There is also sometimes direct cooperation, as in the case of the Phobos probes and of several Venus probes. This cooperation has continued even at times when the official relations between the two countries were very poor. John Roberts roberts@cmr.icst.nbs.gov ------------------------------ End of SPACE Digest V9 #372 *******************