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 ; Wed, 15 May 91 02:34:17 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 15 May 91 02:34:12 -0400 (EDT) Subject: SPACE Digest V13 #554 SPACE Digest Volume 13 : Issue 554 Today's Topics: SPACE Digest V13 #534 Re: Shuttle launches Pegasus/SMEX - Alive and Well Re: 14 Astronauts have died for space exploration? Re: Why the space station? Re: Laser launchers (really microwave launchers) Re: Advancing Launch Technology 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 ---------------------------------------------------------------------- ReSent-Message-ID: Resent-Date: Mon, 13 May 91 22:14:05 EDT Resent-From: Tom McWilliams <18084TM@msu.edu> Resent-To: space+@andrew.cmu.edu Date: Mon, 13 May 91 01:41:01 EDT Reply-To: space+%ANDREW.CMU.EDU@msu.edu From: space-request+%ANDREW.CMU.EDU%CARNEGIE.BITNET@msu.edu Subject: SPACE Digest V13 #534 Comments: To: space+@ANDREW.CMU.EDU To: david polito <15432DJP@MSU.BITNET>, Tom McWilliams <18084TM@MSU.BITNET> Subject: Re: Ethics of Terraforming (was Re: Terraforming Venus) >>I myself note that it took us over 3 million years to climb out of our >>gravity well. I wonder why anybody would want to climb back down another >>one? For this reason I don't think teraforming is a good idea. >> > Perhaps some people *like* living at the bottom of a gravity well. > There are perceived advantages to planet sized habitats. We >know, for example, that at least one such life support system has >continued to provide LSU service for over three billion years with >minimal maintainance (Although the turnover in resident species has been >fairly high); we *don't* know that the tin-can habitats can match that >record. Is it more efficient to creat a life support system that, while >using most of the mass involved to merely generate gravity to contain >the biosphere, persists for billions of years, or is it better to build >myriads of small habitats, whose peak population might be higher, but >whose lifespans might be much lower? Interesting question. It might be illustrative to consider some other examples of biological systems If we could build lots of little habitats, we would without a doubt start filling known space with them. It would probably be not long before other star systems started filling up. Invoke your favorite SF story here. Now, though the lifespans of each colony would be tiny compared to the life- span of the planet, the lifespan of the planet would be tiny compared to the lifespan of the civilization (since we would no longer be doomed by the Sun's imminent Red-giant expansion) For 'colonies' substitute "cell", for 'planet' substitute "body", and for 'civilization' substitute "species". Substitute 'old age' for 'Sun's death' and the analogy with another aspect of biology is complete. Similarly, though the colony is much more fragile than a planet, there are so many of them that it makes up for their fragileness. A good analogy here would be the MayFly season in Detroit (Cars skid on their dead bodies in the street. Like snow in June. Disgusting.) Though millions die because of the inability of their weak little bodies to compete with a harsh world, they come back every year, to the chagrin of the populace and the joy of the birds. But alas, the Earth too is fragile! Though the Earth is killable with the power we command (as well as it's unfortunate placement in a solar system full of Asteroids), it is doubtful if any one act of Nature or Man could kill everyone, if there were colonies at all inclinations and distances from the Sun. This could apply not only to military action (which would be inevitable in the rich-resource era that would inevitably follow any large-scale space industial development) But also pollution, disease, social strife, cultural decay, bad music, etc. would no longer be powerful enough to destroy civilization. Having a few planets would not gain this advantage the way a few thousand colonies would. And if there was some sort of military action, what would stop those in the colonies from using Earth's gravity well to propel missiles (rocks) on their enemies? We just bombed the piss out of the 'cradle of civilization' for Saddam. We'd do it again. So what if it's earth? The Greeks believed that the Children vanquish the Parents. We're doing it now, and we don't have any place to go after it's wrecked. Being born on a colony, you'd care less about the planet. Just my imagination going full speed. sorry. Tommy Mac Acknowledge-To: <18084TM@MSU> ------------------------------ Date: 13 May 91 16:32:04 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Shuttle launches In article <1991May12.034146.19113@ncsu.edu> dfrobins@eos.ncsu.edu (DAVID F ROBINSON) writes: >Was there ever any consideration for launching the shuttle off of the carrier >aircraft... There is no aircraft on Earth that could carry a fueled shuttle stack. The orbiter, with no fuel at all on board, is a full load for a 747. People have proposed rather smaller shuttle analogs launched from 747-back. Nobody has yet funded one. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 13 May 91 17:41:03 GMT From: dftsrv!dpalace@mimsy.umd.edu (Dick Palace) Subject: Pegasus/SMEX - Alive and Well There has been some interest in Small Explorers (SMEX) and a lot of interest in Pegasus. The SMEX program was to have used the Scout Launch Vehicle, and indeed the first SMEX called SAMPEX for (Solar Anomalous and Magnetospheric Particle Explorer) will be launched from the WTR (Western Test Range) in June of 1992. The next two Small Explorers will be launched aboard the Pegasus Vehicle. The Special Payloads Division here at the Goddard Space Flight Center (GSFC) will have the responsability of supplying the data handling and attitude control hardware and electronics plus integrating and testing the payload to the above mentioned subsystems. I'll give you what information that I have on the next two SMEX launches. -------------------------------------------------------------------------- FAST Fast Auroral Snapshot Explorer Principal Investigator: C.W. Carlson, University of California at Berkeley Instruments: EESA - Quadrispherical Electrostatic Electron Analyzer. University of California at Berkeley TEAMS - Time-of-Flight Energy Angle Mass Spectrograph. University of New Hampshire, Lockheed-Palo Alto. EFPE - Electric Field Plasma Experiment. University of California at Berkeley Magnetometer. University of California at Los Angeles Planned delivery to GSFC: January 1994 Launch: September 1994 - Wallops Flight Facility Vehicle: Pegasus Lifetime: 1 Year Orbit: 350X4200 KM Altitude, 83 Deg. Inclination ---------------------------------------------------------------------------- SWAS Submillimeter Wave Astronomy Satellite Principal Investigator: G.J. Melnick, Smithsonian Astrophysical observatory (SAO) Instrument: Telescope - Ball Aerospace Systems Group Submillimeter Receiver System - Millitech Corporation AOS - Acousto-optical Spectrometer. University of Cologne, West Germany Planned delivery to GSFC: June 1, 1994 Launch Date: June 1995 Vehicle: Pegasus Launch Site: Wallops Flight Facility Lifetime: 3 Years Orbit: 500-600 Circular, 38Deg. Inclination Weight: 123.3 Lbs. Instrument Telemetry: 12 KBPS Continuous, 130 MBYTES per day. For those who want to know about SAMPEX I'll include it. -------------------------------------------------------------------------- SAMPEX Solar Anomalous and Magnetospheric Particle Explorer Principal Investigator: G.M. Mason, University of Maryland Instruments: Leica - Low Energy Ion Composition Analyzer. University of Maryland HILT - Heavy Ion Large Telescope. Max-Planck Institute, Garching, West Germany MAST/PET - Mass Spectrometer Telescope/Proton-Electron Telescope California Institute of Technology/GSFC DPU - Data Processing Unit. Aerospace Corporation Delivery to GSFC: August 1991 Launch Site: Western Test Range Launch Date: June 1992 Vehicle: Scout Lifetime: 3 year goal Orbit: 560X700 Km Altitude Circular, 82 Deg. Inclination - not sun Synchronous. Instrument Weight: 90 Lbs. There you have it, all I know at this time. Please! Please! don't flood me with E-Mail for other details. What I gave is what I know. If and when I get updates I will pass them along. General questions on Goddard, or the Special Payloads Division, I would most happily answer it I can. Dick I an not responsible for typos, even if I made them 8-) -- Dick Palace Goddard Space Flight Center (301) 286-9464 dpalace@sunland.gsfc.nasa.gov ------------------------------ Date: 13 May 91 18:56:41 GMT From: pioneer.arc.nasa.gov!shafer@icarus.riacs.edu (Mary Shafer -- OFDD) 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: [In reference to the Astronaut Memorial] >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. >A couple have did flight testing aircraft that was not related to >space exploration and a couple have did in car accidents...I think. There are 17 deceased US astronauts. This number from the JSC PAO Library last week. Elliot See and another died in the McAir parking lot when their T-38 clipped the corner of the building in the fog. Sunny Carter died in a commuter airline crash (with John Tower). One of the Navy guys died in a airplane crash (maybe doing aerobatics?) One of the really early guys (Mitchell?) died of a heart attack. 172 astronauts total, 88 current, 67 retired or reassigned, 17 deceased. There are also 23 astronaut candidates. -- 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 ------------------------------ Date: 13 May 91 21:29:13 GMT From: pasteur!dog.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: Re: Why the space station? In article <1991May13.185146.7084@sequent.com> szabo@sequent.com writes: >>The smaller probes definitely don't need assembly. The bigger ones really >>could use it. Just look at some of the elaborate schemes people have put >>together trying to do a Mars sample return ... > >Care to expand on this? I fail to see how in-orbit assembly makes >a sample return, from Mars or other places, any easier. It makes a bigger vehicle possible, because you can add an upper stage launched separately. The studies I've seen have all concluded that doing a Mars sample return -- at least, the sort of sample return the Mars people would like, bearing in mind that they'll probably only get one of them -- with one Titan-IV-Centaur payload is just not practical. Which means playing elaborate games of one kind or another to split it up. >Note that both the Soviet Union and the U.S. did extensive sample >return from the Moon without in-orbit assembly. The US did it using a heavy booster which is no longer available. The Soviets used a Titan-class booster and got a bare-minimum sample return with no frills, from an airless planet with half as much gravity that is close enough to make navigation much easier and avoid a long cruise phase. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 14 May 91 16:47:07 GMT From: dog.ee.lbl.gov!hellgate.utah.edu!caen!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: Re: Laser launchers (really microwave launchers) In article <4437@undis.cs.chalmers.se> johnsson@cs.chalmers.se (Thomas Johnsson) writes: >I wonder if anyone has considered beaming the power to the launch >vehicle using microwaves instead of a laser... If you want to deliver it as electrical energy, microwaves are superior. But the longer wavelength makes them much harder to beam tightly, and also makes it awkward to arrange for them to be absorbed in a thin layer of reaction mass (which is what laser launchers do). Beaming power to run electric rockets of one kind or another (e.g. ion rockets) has potential, but the low thrust limits its usefulness for Earth-to-orbit launch. The laser launcher looks better for that. Doubtless Gary Coffman is going to reiterate at length why laser launchers are silly and won't work. Sorry, Gary, given a choice of believing you or believing people like Arthur Kantrowitz and Jordin Kare (head of the LLNL laser-launcher group), you lose. Look up that conference proceedings I referenced a little while ago if you want to find out why laser launchers will work. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 14 May 91 18:05:13 GMT From: prism!ccoprmd@gatech.edu (Matthew DeLuca) Subject: Re: Advancing Launch Technology In article dlbres10@pc.usl.edu (Fraering Philip) writes: [replying to Gary Coffman] >1. Assembly in space may be a lot cheaper and easier than you think. >Since the Russians can do it with their rather less developed automation, >shouldn't it be easier with the more developed technology here? The Russians haven't actually done any assembly in space of the nature that is being talked about. What they *have* done is dock lots of capsules together, which isn't particularly more sophisticated than what we and they have been doing for the last twenty-five years. >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... Cost-per-pound is frequently a fallacy. The important number to look at is how much it costs to get your payload into orbit. If I have a fifty pound payload to put up, and I put it on a bare-bones $5 million rocket, I am paying $100,000 per pound. If it's worth the $5 million I paid, though, then I got a good deal. In my opinion, this is why there is going to be a solid market for the small booster; universities and private companies can afford the few millions of dollars a small rocket must cost to do some basic research, whereas they cannot begin to afford the fifty-million dollar costs of the current rockets we are using. -- Matthew DeLuca Georgia Institute of Technology "I'd hire the Dorsai, if I knew their Office of Information Technology P.O. box." - Zebadiah Carter, Internet: ccoprmd@prism.gatech.edu _The Number of the Beast_ ------------------------------ End of SPACE Digest V13 #554 *******************