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, 13 May 91 01:48:06 -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, 13 May 91 01:48:01 -0400 (EDT) Subject: SPACE Digest V13 #536 SPACE Digest Volume 13 : Issue 536 Today's Topics: Space Sience vs Space Engineering. Will AXAF be cut Re: Another Galileo Sulution Re: Saturn V and the ALS Re: Laser launchers (really tethers) Re: Terraforming Mars? Why not Venus? Science vs. Exploration (was Re: Why the space station?) Re: Ethics of Terraforming (was Re: Terraforming Venus) Re: Why the space station? (Really Docking) New CD-ROMs on-line at Ames 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: 8 May 91 00:45:01 GMT From: mintaka!think.com!rpi!usc!jarthur!nntp-server.caltech.edu!news@bloom-beacon.mit.edu (Steinn Sigurdsson) Subject: Space Sience vs Space Engineering. Will AXAF be cut Word is going around that in the next week Congress will decide the immediate future of the US space program, the choice being between cancelling or delaying Space Station Fred and retaining AXAF, SIRTF and the space science program, on the one hand, or going ahead with Fred, and cancelling or delaying AXAF, SIRTF and other space science programs. As I understand it, no money can be moved into the appropriations category NASA comes under, and with the VA and HUD competing for funds, something will be cut to balance the budget - and it will not be the VA. The Astronomy community is asking scientists to write congress to express their opinion on the issue. ie Tell them to cut Fred. Personally I would hate to see the Space Station cut, but in a straight choice between AXA/SIRTF and Fred would choose AXA/SIRTF. The Space Station is not currently justified scientifically, although I think it is an excellent engineering project, and even more important at the motivational level so recently derided in "What's New in Physics". I would ask people to take a few minutes to write to congress and express their opinions on the issue - even if you disagree. Addresses provided by J. Bahcall: ========================================================================== HOUSE: APPROPRIATIONS COMMITTEE SUBCOMMITTE on HUD \& Independent Agencies Democrats Republicans Bob Traxler, MI, CHAIRMAN Bill Green, NY, RANKING MIN. Rm. 2366 Rayburn House Office Bldg. Rm. 2301 Rayburn House Office Bldg. Louis Stokes, OH Lawrence Coughlin, PA Rm. 2365 Rayburn House Office Bldg. Rm. 2309 Rayburn House Office Bldg. Alan Mollohan, WV Bill Lowery, CA Rm. 229 Cannon House Office Bldg. 2433 Rayburn House Office Building Jim Chapman, TX 236 Cannon House Office Building Chet Atkins, MA 123 Cannon House Office Building Marcy Kaptur, OH 1228 Longworth House Office Building Staff: Richard Malow H 143 The Capitol All addresses are Washington D.C. 20515 =============================================================================== =============================================================================== SENATE APPROPRIATIONS COMMITTEE SUBCOMMITTEE: HUD and Independent Agencies Democrats Republicans Barbara Mikulski (MD), CHAIRMAN Jake Garn (UT), RANKING MIN. Rm. 320 Senate Hart Office Bldg. Rm. 505 Senate Dirksen Office Bldg. Patrick Leahy (VT) Alfonse D'Amato (NY) Rm. 433 Senate Russell Office Bldg. Rm. 520, Senate Hart Office Bldg. J. Bennett Johnston (LA) Don Nickles (OK) Rm. 136 Senate Hart Office Bldg. Rm. 713 Senate Hart Office Bldg. Frank Lautenberg (NJ) Phil Gramm (TX) Rm. 506 Senate Hart Office Bldg. Rm. 370 Senate Russell Office Bldg. Wyche Fowler, Jr. (GA) Kit Bond (MO) Rm. 204 Senate Russell Office Bldg. Rm. 293 Senate Russell Office Bldg. J. Robert Kerrey (NE) Rm. 316 Senate Hart Office Bldg. STAFF: Kevin Kelly 142 Senate Dirkson Office Building All addresses are Washington D.C. 20510 =============================================================================== Phone numbers: Congressman Traxler: 202-225-2806 Senator Mikulski: 202-224-4654 ------------------------------ Date: 29 Apr 91 17:17:57 GMT From: news-server.csri.toronto.edu!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: Re: Another Galileo Sulution In article <0DA4D13D00402195@UALR.BITNET> RDBROWN@UALR.BITNET writes: >Although putting a communications relay satellite in orbit around Jupiter >is a good idea, one must remember that Jupiter's position changes during >it's year, sometimes making it even further away from Galileo than Earth >would be. Uh, how is this relevant? We don't care (that much) about the data Galileo will be sending until it too is in Jupiter orbit. Despite some small side trips along the way, Galileo's mission in life is to be a Jupiter orbiter. >Another possibility would be to launch a relay station into a trajectory >aimed directly at Galileo, thus the relative position between it and >Galileo remain unchanged. Relay-1 can then take on the task of tracking >Earth. ... Unfortunately, this means Relay-1 also has to be able to receive from Galileo. The whole point of putting a relay into Jupiter orbit is that it will be *close* to Galileo, so it can get a decent data rate without needing a large antenna and precision pointing. A small spacecraft halfway between Earth and Jupiter is not going to be able to compete with DSN's huge ground-based antennas with liquid-helium-cooled maser amplifiers. Doubling the distance only cuts the signal strength by a factor of 4, and DSN's massive equipment performs better than a small relay satellite by a far larger margin than that. Relay satellites make sense only in Galileo's odd situation, and only if they are orders of magnitude closer to Galileo than Earth is. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 8 May 91 19:31:38 GMT From: dog.ee.lbl.gov!hellgate.utah.edu!caen!ox.com!hela!aws@ucbvax.Berkeley.EDU (Allen W. Sherzer) Subject: Re: Saturn V and the ALS In article <1991May8.131527.1@vf.jsc.nasa.gov> kent@vf.jsc.nasa.gov writes: >> But this number is interesting. Two contractors have offered to build >> for a fixed price launchers which will launch 100K pound payloads. They >> will do it in half the time and 5% of the cost of ALS. Operational costs >> of these launchers would be about the same as ALS. >5 % ? who are the contractors? what are their track records ? >I'll believe it when I see it. "There aint no such thing as a free lunch." The contractors are McDonnell Douglas and Martin Marietta. Both vehicles are heavy lift versions of their existing launchers. In both cases something like 95% of the launchers consists of off the shelf parts. Both have offered to build the vehicle under a commercial acquisition for a fixed price. For more information see my last three "One Small Step..." collumns or the Sept. 1990 issue of Aerospace America. These vehicles will meet NLDP operaitonal cost yet cost less than one Shuttle flight to build. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | Allen's tactics are too tricky to deal with | | aws@iti.org | -- Harel Barzilai | +---------------------------------------------------------------------------+ ------------------------------ Date: 8 May 91 19:56:18 GMT From: aio!ecfa!matthews@eos.arc.nasa.gov (Michael C. Matthews) Subject: Re: Laser launchers (really tethers) In article <2777@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes: >In article <21620@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: >>In article <2753@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes: >>>Tethers need to exceed the theoretical strength of materials limits by >>>orders of magnitude to work. >> >>Kevlar can work today for most of the scenarios envisioned. >>The major problem is launch cost of the mass. This can be brought >>way down by (a) manufacturing the tethers in space, (b) producing >>better tensile materials -- a very important and woefully underfunded >>field of R&D, (c) bootstrapping larger tethers into orbit with smaller >>tethers, or (d) a combination of the above. > >A one square inch kelvar tether to geosync orbit would weigh 45.2 million >pounds. I don't have the handbook here at the terminal, but kelvar doesn't >approach 45 million pounds per square inch tensile strength by orders of >magnitude. It couldn't support itself, much less a usable payload. > Please don't confuse "tethers" with "beanstalks": the latter is a special case of the former and is generally considered to be centuries (or at least several decades) away from practicality, while tethered satellite technology is ready to fly next year (assuming the shuttle schedule holds). There are many applications of tethers in the 1-km to 1000-km range that provide much promise for momentum scavenging/ transfer/banking and electrodynamic energy storage applications, which could be practical in the next decade or two. For these kinds of tether lengths, Kevlar is quite adequate, and stuff like Spectra is great for "disposable" tethers. I do have to admit to some doubts about being able to drastically reduce launch costs with such systems, due to their operational and dynamic complexity. I imagine that scheduling for a "rolling skyhook" system would be a nightmare, and prox ops would be... uh... "dramatic". -- Mike Matthews matthews@asd2.jsc.nasa.gov Tethered Vehicle Analysis Group, Advanced Projects Section Navigation, Control, and Aeronautics Department Lockheed Engineering & Sciences Company, Houston, Texas ------------------------------ Date: 9 May 91 04:18:09 GMT From: mintaka!ai-lab!life.ai.mit.edu!guest@bloom-beacon.mit.edu (Guest Account) Subject: Re: Terraforming Mars? Why not Venus? In article <1991May8.025908.11231@agate.berkeley.edu> fcrary@headcrash.Berkeley.EDU (Frank Crary) writes: >The idea of a skintight suit (the Space Activity Suit was the name of the >only real design, and didn't work too well.) is all about how the pressure >s maintained. It has nothing to do with thermal control. The Space Activity Suit doesn't have a cooling system. The wearer cools himself as his sweat passes through the gore-tex. And besides, the SAS was promising. it would probably be better than the ones in use today if the same inordinate amount of money was thrown at it. ------------------------------ Date: 9 May 91 05:01:59 GMT From: rochester!sol!yamauchi@louie.udel.edu (Brian Yamauchi) Subject: Science vs. Exploration (was Re: Why the space station?) In article <1991May9.025939.31508@uokmax.ecn.uoknor.edu> rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes: >henry@zoo.toronto.edu (Henry Spencer) writes: >>In article <1991May7.024811.8157@uokmax.ecn.uoknor.edu> rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes: >>>... I see no signs that the >>>exploration of the solar system is really limited by the lack of an >>>orbital base. There is an IMMENSE amount of science that can be done >>>with present technology... >>You are assuming that "science" and "exploration" are synonymous; care to >>explain this? >what I mean by exploration is discovering the story of the origin of >planets of life, the nature of the mantle and accretion on other solar >system bodies, how the earth was formed, how it works. All of these are worthwhile questions; some may be answered through exploration; but none *are* exploration. Columbus wasn't doing science, and neither were Lewis and Clark. Einstein and Newton weren't doing exploration. In space, the two fields overlap greatly, but it's a mistake to get them confused. Sending Voyager to Neptune is exploration -- analyzing the atmospheric currents on Neptune is science. They are closely related, but they are not the same thing. -- _______________________________________________________________________________ Brian Yamauchi University of Rochester yamauchi@cs.rochester.edu Department of Computer Science _______________________________________________________________________________ ------------------------------ Date: 10 May 91 23:09:32 GMT From: pyramid!lstowell@hplabs.hpl.hp.com (Lon Stowell) Subject: Re: Ethics of Terraforming (was Re: Terraforming Venus) In article jimcat@itsgw.rpi.edu (Jim Kasprzak) writes: > The point is, even if we manage to terraform Mars,........ >........................ If it were up to me, I'd designate >Olympus Mons and the other Tharsis volcanoes as permanent wilderness >areas, along with most of Valles Marineris. That's a pretty big >chunk of the planet, but it still leaves a lot for human habitation. > But what about the face? (Does anyone else think it sorta looks like Maggie Thatcher?) If I recall the strange martian chemistry, unless the human habitats are kept sealed such that no H20 gets into the martian atmosphere, there would likely be some chemical reactions that may destroy some of the natural features. Having a whole planet as a park? Why not? If we have the engineering resources to terraform, we would also have the ability NOT to do so, but still create quality life areas for our future population--which i still predict will slow down its growth as education and lifestyle choices become more widely available. ------------------------------ Date: 10 May 91 03:12:18 GMT From: wuarchive!rex!rouge!dlbres10@decwrl.dec.com (Fraering Philip) Subject: Re: Why the space station? (Really Docking) Also, the Soviets use a different sort of docking approach than NASA spacecraft have. They supposedly do this to save fuel. I think Henry posted the details a while back. -- Phil Fraering dlbres10@pc.usl.edu ''It's a Flash Gordon/E.E. Smith war, with superior Tnuctip technology battling tools and weapons worked up on the spot by a billion Dr. Zarkovs.`` - Larry Niven, describing the end to _Down in Flames_. ------------------------------ Date: 30 Apr 91 00:00:03 GMT From: usenet@ames.arc.nasa.gov (Peter E. Yee) Subject: New CD-ROMs on-line at Ames Two new CD-ROMs are now available for anonymous ftp. The first is Volume 3 of the Voyagers to the Outer Planets series. This contains Uranus images, including the all images in the browse format (200 x 200). I suggest that you get browse images first and then record the names of the images that you would like to retrieve in full size. Not all full size images are on this disc. Each of these two discs contains browse images for about 2 other discs. The second disc that is on-line is Volume 12 of the Voyagers series and contains Neptune data, again including browse-sized images. Technical, machine readable descriptions of the discs may be found in the file called voldesc.sfd on each disc. And I would like to reiterate my earlier request that if you do use this data in any report, publication, or formal presentation, that you make the following credits: For Voyager data: Dr. Bradford A. Smith For Magellan data: Dr. Gordon H. Pettengill And for all data: Planetary Data System National Space Science Data Center Enjoy! -Peter Yee yee@ames.arc.nasa.gov ames!yee PS For those of you who missed the details of how to access these discs, you need to use anonymous ftp to ames.arc.nasa.gov. The CD-ROMs are mounted as /pub/SPACE/CDROM and /pub/SPACE/CDROM2. Use of the first CD-ROM drive is courtesy of Randall Robinson, Communications Operations Branch, NASA Ames Research Center. ------------------------------ End of SPACE Digest V13 #536 *******************