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 ; Thu, 16 May 91 01:38:59 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 16 May 91 01:38:51 -0400 (EDT) Subject: SPACE Digest V13 #556 SPACE Digest Volume 13 : Issue 556 Today's Topics: Re: 14 Astronauts have died for space exploration? Progress? (was: Re: Ethics of Terraforming) Re: Honking at cyclists... Re: R-100 and R-101 Re: 14 Astronauts have died for space exploration? Re: SPACE Digest V13 #516 Re: Tethers (was Re: Laser launchers) Re: Advancing Launch Technology New Subject--Solar Collectors/Antimatter Re: Saturn V and the ALS 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: 15 May 91 01:33:20 GMT From: agate!lightning.Berkeley.EDU!fcrary@ucbvax.Berkeley.EDU (Frank Crary) Subject: Re: 14 Astronauts have died for space exploration? In article A20RFR1@MVS.CSO.NIU.EDU (Bob Rehak Ext. 3-9437, AIS Central Services - Swen Parson 146) writes: >14 astronauts? Last time I counted there were only 10. > >Apollo I: Grissom, White, and Chaffee. >STS-61L Challenger: Scobee, Smith, Resnik, Onizuka, McNair, > Jarvis, and McAuliffe. The remaining four are Soviet Kosmonauts: Soyuz 1: 23 April 1967: Vladimir M. Komarov Soyuz 11:29 June 1971: Viktor I. Patsayev Georgi T. Dobrovolsky Vladislav N. Volkov All rumors to the contrary, there is NO evidence of farther Soviet space fatalities. Frank Crary UC Berkeley ------------------------------ Date: Tue, 14 May 91 08:42:57 PDT From: greer%utdssa.dnet%utadnx@utspan.span.nasa.gov X-Vmsmail-To: UTADNX::UTSPAN::AMES::"space+@andrew.cmu.edu" Subject: Progress? (was: Re: Ethics of Terraforming) In SPACE Digest V13 #545, VAX1.CC.UAKRON.EDU!mcs.kent.edu!usenet.ins.cwru.edu!agate!lightning. Berkeley.EDU!fcrary@tut.cis.ohio-state.edu (Frank Crary) writes: >In article <265@rins.ryukoku.ac.jp> will@rins.ryukoku.ac.jp (will) writes: >... >> Also, if there was life before, and it was lost, it should be discovered >> and studied. A lot must be done before we go and wipe out a planet just >> for our own use. Seems very selfish to me. >It may very well be selfish. However I am an avowed racist: I am strongly >biased in favor of the human race. If the growth and welfare of the >human race requires the loss of fosilized Martian pond scum, or even >now living micro organisims, I say the Martians loose. > > Frank Crary > UC Berkeley Talk about being a slave to your genes! It's just this sort of "damn everything but humans" attitude that has wrought so much havoc to date. I used to be pretty gung ho about humans expanding into space, but a few years of reading SPACE Digest has cured me of that. How sad it would be if the net result of ten billion years of preparation plus five billion years of evolution was to spread MacDonald's to the far corners of the universe. _____________ Dale M. Greer, whose opinions are not to be confused with those of the Center for Space Sciences, U.T. at Dallas, UTSPAN::UTADNX::UTDSSA::GREER "A tree's a tree. How many more do you need to look at?" - Ronald Reagan ------------------------------ Date: 14 May 91 23:10:00 GMT From: snorkelwacker.mit.edu!think.com!spool.mu.edu!news.nd.edu!mentor.cc.purdue.edu!f3w@bloom-beacon.mit.edu (Mark Gellis) Subject: Re: Honking at cyclists... Regarding the growth of humans into space, may I recommend a volume called INTERSTELLAR MIGRATION AND THE HUMAN EXPERIENCE, edited by Finney and Jones, and especially the article by David Criswell on space industrialization. Criswell makes some interesting claims, suggesting that humanity should eventually dismantle the sun, converting it into a smaller and longer-lived star and using the nearly two octillion tons of hydrogen, helium, and other elements gleaned by "sun-lifting" to build and power habitats. He estimates we could have 80 quadrillion people living in the solar system, each person having millions of tons of raw materials at their beck and call. Interesting stuff. ------------------------------ Date: 14 May 91 13:37:37 GMT From: eru!hagbard!sunic!mcsun!ukc!acorn!ixi!clive@bloom-beacon.mit.edu (Clive Feather) Subject: Re: R-100 and R-101 In article <1991Apr20.050747.9078@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >The R-101 had grave trouble flying at all, needed hasty and ill-advised >lengthening to have any hope of meeting its performance specs, and was >generally over budget, behind schedule, and below expectations... and on >its maiden voyage to India, this flagship of socialist progress crashed >on a hillside in France with no survivors. There are several ex-R101 crew members who would be surprised to hear that. I can provide names if you want. I think that some of them might still be alive. -- Clive D.W. Feather | IXI Limited | If you lie to the compiler, clive@x.co.uk | 62-74 Burleigh St. | it will get its revenge. Phone: +44 223 462 131 | Cambridge CB1 1OJ | - Henry Spencer (USA: 1 800 XDESK 57) | United Kingdom | ------------------------------ Date: 15 May 91 00:00:07 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!samsung!news.cs.indiana.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!ibma0.cs.uiuc.edu!sunc1.cs.uiuc.edu!noe@tut.cis.ohio-state.edu (Roger Noe) Subject: Re: 14 Astronauts have died for space exploration? In article <1991May14.020037.7174@agate.berkeley.edu> morrison@ucsee.Berkeley.EDU writes: >The May 13 Newsweek has an article on the memorial. They say that >the fourteen are the three Apollo I astronauts, the seven Challenger >astrounauts and Charles A. Bassett II, Theodore C. Freeman, Elliot M. See Jr., >and Clifton C. Williams Jr. who all died in airplane crashes. Make it 15. I think it has already been announced that "Sonny" Carter's name will be added to the memorial shortly. -- Roger Noe roger-noe@uiuc.edu Department of Computer Science noe@cs.uiuc.edu University of Illinois 40:06:39 N. 88:13:41 W. Urbana, IL 61801 USA ------------------------------ Date: 15 May 91 04:07:44 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!sdd.hp.com!spool.mu.edu!uwm.edu!ogicse!sequent!muncher.sequent.com!szabo@tut.cis.ohio-state.edu Subject: Re: SPACE Digest V13 #516 In article <28990@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: >How does any of what you said apply to Galileo? Never said it did; my apologies for not being clearer on that point. I agree with you, Galileo is built for Jupiter and its moons and should go there if at all possible (while flying by asteroids on the way if possible). I was answering your comment about exploration's ability to change timetables. The discovery of small asteroids and comets via infrared telescope would radically shrink the expense, and therefore the timetable, of capture missions. Solving several outstanding problems relating to earth-crossing resources, including the distribution of water, the existence of nickel-iron regolith, and the source of ureleite diamonds could also create the motivation to invest in mining. For that matter, the discovery of ore-forming processes on Io's heavily differentiated, sulfide-rich surface could also shorten timetables. (Although, mining that would be one heck of a challenge. :-) Sulfides and differentiation are the primary drivers for ore-forming processes on Earth, but they exist to a much greater degree on Io. In any case, if they get the antenna unstuck it will be a very happy day. >However, my >point was that diverting Galileo from its mission will have absolutely >no effect on the rate of our advancement towards this level of space >exploitation, Well, _probably_ not. With exploration, never say never. But infrared telescope satellites, asteroid sampling in Antartica, visual searches, and more specialized flyby and sampling probes would be superior to extra Galileo flybies. -- Nick Szabo szabo@sequent.com "If you understand something the first time you see it, you probably knew it already. The more bewildered you are, the more successful the mission was." -- Ed Stone, Voyager space explorer ------------------------------ Date: 14 May 91 18:07:49 GMT From: sdd.hp.com!cs.utexas.edu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!aurora.physics.utoronto.ca!neufeld@ucsd.edu (Christopher Neufeld) Subject: Re: Tethers (was Re: Laser launchers) In article <2817@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes: > >Let's look at a typical strawman tether launch. Let's propose a 1000 km >tether whose center of mass is in a 700 km orbit. To hook on to the >lower end of the tether, you need to be going faster than the orbital >velocity of a 700 km orbit and be at an altitude of 200 km. If you've >already gone that far, you've paid most of the cost to orbit. > No, that's not right. If the tether is rotating, resembling the spoke of an invisible wheel rolling around the surface of the Earth, then the velocity of the tip drops to zero briefly. A person standing on the ground would see the tether come in from a high angle, straightening out until it was coming straight down, stop, then take off in the upward direction and shoot away in a high angle along the ground path of the tether. The payload could be attached from a hot air balloon if you really thought it was necessary. The size of the tether establishes the accelerations of the payloads. Note that the upper end of the tether is going at twice orbital velocity, so it's above escape. The tether, then, is taking a stationary object from the upper atmosphere, and delivering it to interplanetary space without that object having to burn any fuel. The tether can now take a week or a month to boost its orbit with high Isp engines and be ready for the next payload. If you don't want to go out into interplanetary space you can just let go of the tether a bit earlier, and bring along an apogee thruster to circularize the orbit. >So the >tether doesn't buy you that much. And you've added considerable Rube >Goldberg complication to the scheduling of your launch. Above an airless >body like the Moon, a tether begins to make a lot of sense. But for >Earth based launches, you've got to keep the end of the tether above >the majority of air resistance or it'll end up in your lap. > Clearly it can buy you quite a bit. You have to watch out for air effects, but the tether is moving quite slowly relative to the ground when it's in air. You might be able to get away with a tether which drops down to a couple of dozen kilometres altitude without too much trouble with air, and a cargo aircraft to that altitude costs considerably less than a rocket which carries the same payload to Earth escape, even when you figure in the fuel which the tether will need to consume in order to maintain its orbit. If the air is thick enough to bother a tether, it's probably thick enough to hold an airplane up, so they should be able to mate nicely. The airplane doesn't have to be going anywhere near orbital velocity. >It always comes back to fighting that pesky air. That's why I keep >harping on turning that liability into an asset by using wings and >air breathing engines to get above most of it. > That's exactly what you'd do with such a tether system. The tether would represent a significant advantage in getting the payloads out, though. >Gary -- Christopher Neufeld....Just a graduate student | Flash: morning star seen neufeld@aurora.physics.utoronto.ca Ad astra! | in evening! Baffled cneufeld@{pnet91,pro-cco}.cts.com | astronomers: "could mean "Don't edit reality for the sake of simplicity" | second coming of Elvis!" ------------------------------ Date: 14 May 91 20:57:46 GMT From: mintaka!think.com!zaphod.mps.ohio-state.edu!caen!ox.com!hela!aws@bloom-beacon.mit.edu (Allen W. Sherzer) Subject: Re: Advancing Launch Technology In article dlbres10@pc.usl.edu (Fraering Philip) writes: >2. Currently it looks like it is the small booster which can take >business away from the larger one in spite of a cost per pound >imbalance in favor of the larger booster. My example, again, is >Pegasus... This is not a flame but I think you missed the boat here. No payloads have gone from the larger ones to the smaller ones. It therefore cannot be said that they are loosing buisness. What IS happening is that we are seeing a new market develop. This is not taking buisness away but rather adding more buisness. In other words, making the pie bigger. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | Allen's tactics are too tricky to deal with | | aws@iti.org | -- Harel Barzilai | +---------------------------------------------------------------------------+ ------------------------------ Date: 14 May 91 23:04:13 GMT From: dog.ee.lbl.gov!hellgate.utah.edu!caen!sdd.hp.com!spool.mu.edu!news.nd.edu!mentor.cc.purdue.edu!f3w@ucbvax.Berkeley.EDU (Mark Gellis) Subject: New Subject--Solar Collectors/Antimatter I have a question or two regarding possible future applications of solar power. Robert Forward suggests that it is possible to produce antimatter with a reasonable degree of efficiency. His design, however, calls for a lot of power. Now, since the use he suggests for antimatter is rocket fuel (his argument, which I accept, is that it is so expensive that fusion and solar are really much better for most other power requirements), it makes sense to bring in other space-related technologies. If you have a space-based economy a few hundred years down the line, you need a LOT of antimatter if you want people zipping around the solar system. You especially want antimatter if you start colonizing the cometary halo-- lots of organics out there, so people will probably go there eventually-- where the distances require you to have fairly fast spaceships. (Fusion- driven spacecraft will have cheaper fuel requirements since deuterium is not particularly rare, but antimatter allows much greater velocities.) My question regards the efficiency of solar collectors. Now, obviously, technology will change and improve during the next few centuries, but based on what we know today about such solar power cells... 1) Given a solar cell that will produce 10 kilowatts in Earth orbit, would the same cell (i.e., the same mass of finished product) produce more power if it was moved to Venus orbit, where it would be getting more than twice as much energy from sunlight? (If power is the wrong word, I apologize; you know what I mean, though.) Will it produce 20+ kilowatts now? Do the cells have a limit on how much electricity they will produce, or will they just keep giving you more power if you increase the solar energy per square meter? (I ask this question because if you can do this, it is probably much cheaper to produce a certain amount of solar cells and move them into a close orbit around the sun, as opposed to building more and keeping them where you build them.) 2) If you can get more energy from solar cells by moving them closer to a star, what is the limit? First, is there a point where the cells simply will not put out more energy, no matter how much sunlight they get. Also, there is obviously a point where the cells will melt, but where is that? Could we build solar power stations, say, in Mercury orbit, where we would be getting more than six times the sunlight we get in Earth orbit? (Obviously, it depends on the materials involved. Also, clearly, solar cells are getting better all the time, and we cannot predict what technology will be like in the far future, but I would appreciate speculations based on existing technology.) Thanks in advance. Mark Gellis f3w@mentor.cc.purdue.edu ------------------------------ Date: 14 May 91 02:26:37 GMT From: skipper!shafer@ames.arc.nasa.gov (Mary Shafer) Subject: Re: Saturn V and the ALS In article <9105121528.AA27759@iti.org> aws@ITI.ORG ("Allen W. Sherzer") writes: Fair enough. But please do read the article in the September 90 issue of Aerospace America. If for no other reason then you owe it to yourself to be as informed as you can be. Well, as a 15-year member and an Associate Fellow of AIAA, married to an AIAA Fellow with over 20 years of membership (including chairing the AFM TC and it's conference), it's my opinion that Aerospace America is not necessarily informational. Study the list of authors some time. You'll notice that none of them have any technical qualifications. Every now and then they'll let a technical person write an article, but they then edit it into incomprehensibility and don't give the technical person a chance to review it. For this reason, many people refuse to contribute to it any more. The various Journals, however, are still of high quality and definitely worth reading. (Even though I can't see how my paper is _ever_ going to make the page limit!) -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "Turn to kill, not to engage." CDR Willie Driscoll ------------------------------ End of SPACE Digest V13 #556 *******************