Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.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 ; Tue, 8 Jan 1991 01:59:10 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 8 Jan 1991 01:58:39 -0500 (EST) Subject: SPACE Digest V13 #022 SPACE Digest Volume 13 : Issue 22 Today's Topics: Re: solar cells NASA images Re: MIR sweepstakes Re: Recent Newsstand Magazine Articles NASA Headline News for 01/03/91 (Forwarded) Launch of Navstar GPS II-10 and Shutdown of I-6 Re: Interstellar travel 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: 3 Jan 91 00:56:48 GMT From: dweasel!loren@lll-winken.llnl.gov (Loren Petrich) Subject: Re: solar cells The issue of chemical vs. nuclear poisons was brought up yet again. I feel that this anti-nuclear allergy that too many people have will someday be remembered as one of the irrational phenomena of our time. But I doubt that it is worse that the turn-of-the-century enthusiasm for patent medicines made from radium and other radioactive materials. As to chemical poisons being decomposable, that depends on what kind of chemical poison. Heavy metals cannot be chemically decomposed. And some chemical poisons are difficult to decompose, such as chlorinated hydrocarbons. The persistence of certain pesticides like DDT should be well known. True, DDT and other such non-biodegradable substances can be burned at high temperature, but burning at high temperature is just that. I remember some years back that the EPA was hoping to burn some toxic wastes in a ship at sea, but some environmentalists didn't like that idea very much. I keep on being amazed by the anti-RTG movement. They complain that those who send up RTG's on spacecraft have not done comprehensive studies of possible alternatives. Yet I wonder if the anti-RTG people have done anything similar. Consider the difficulties of doing maintenance on a spacecraft, which usually cannot be brought back to its designers. Millions of dollars and months of work go into designing some spacecraft, so it is important that they be likely to keep on working. One should try to use components that need as little maintenance as possible, and RTG's fit the bill very well. They are continuously "on" and have no moving parts. Solar cells are one common alternative, but they tend to degrade over time and they cannot be used in the outer Solar System, due to the extreme dilution of sunlight there. A focused-sunlight system would have several problems. A mirror would have to be kept pointing at the Sun, and the generating system has an abundance of moving parts, which are an all-too-familiar maintenance headache. There is also the problem of replenishing leaked working fluid. And I am not aware of any focused-sunlight system that has ever been used in a spacecraft. Chemical reactions are out of the question. Buth fuel and oxidizer would have to be taken along, which would add a serious amount of weight for a months-long mission. The power sources usually have an abundance of moving parts, and would have to be made redundant for the sake of safety (if one breaks down, the others could keep on moving). Batteries have a minimum of moving parts, but they usually have a very low available power to mass ratio (ask any designer of a battery-powered car). Fuel cells are relatively efficient, but even they have moving-part problems, and they require liquid hydrogen and oxygen, which must be kept away from heat. Systems using combustion can use fuels and oxidizers that are liquid at room temperature, but they also suffer from problems with moving parts -- consider typical turbines and piston engines. So either solar cells or RTG's are the way to go for spacecraft. I presume that this is the standard argument. In fairness to opponents of nuclear energy, I think that there is a sociological question to be considered. Most nuclear energy has been handled as large-scale projects. Simply consider how big a typical nuclear reactor is and how long it takes to build one. Big organizations have to justify their policies, and they often make excuses for keeping on doing what they have been doing. And they sometimes seem insensitive and arrogant. It's just what computers have seemed like in their early years, before personal computers became common. And on the issue of safety, one should ask what kinds of critical tests are possible. It is much easier to perform really tough tests on an RTG than on a nuclear reactor, so one may feel more confidence in their safety. And another possible difficulty with solar cells -- how much energy does it take to make them? They would not be too good if the amount of energy needed to make them was only equal to their output for several years of running. Has that question ever been addressed? $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ 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: 3 Jan 91 16:19:32 GMT From: zaphod.mps.ohio-state.edu!samsung!umich!csd4330a!newsserv!baskins@tut.cis.ohio-state.edu (Bob Baskins) Subject: NASA images Before the Christmas break I recall seeing posted an Internet address in which one could get access to NASA images. Could someone please email me that address? Thanks, -- ===================================================================== Robert Baskins Environmental Research Institute of Michigan ===================================================================== ------------------------------ Date: Thu, 3 Jan 91 08:21:27 -0500 From: "Allen W. Sherzer" Subject: Re: MIR sweepstakes Newsgroups: sci.space Cc: In article <91002.081422GIPP@GECRDVM1.BITNET> you write: >A better issue is: who is this company that is running the lottery? What >are their credentials? I know one of the people involved (Jim Davidson). He has been a very active supporter of space. He worked for SSI (Space Services), Microsat (a space startup), and this venture to develop a space tourism market. In addition, he is active in the local NSS chapter and was on the NSS bord of directors. >If they are merely attempting to turn a profit... I'm sure they would like to make a profit. However, their main goal is to develop space. >Or they could be just hoping that the winner takes the alternative prize >(1.5 million according to one posting). Jim has told me that SOMEBODY will go regardless. If the winner can't/won't go, the second place person will go. The only thing which would prevent the trip would be unforseen political events int he USSR. BTW, the winner gets a choice of $1.5M or the trip and $500K. Second prize is $400K and a trip if the winner can't/won't make the trip. There will be twelve canidates in all. >I seem to recall Henry Spencer gave a good character reference for one of >the main guys in the company, I second Henry's good reference. >How many dreamers/contestants/suckers have called so far? According to Jim Davidson, 'tens of thousands'. Allen -- +----------------------------------------------------------------------------+ |Allen W. Sherzer | America does best when it accepts a challenging mission. | | aws@iti.org | We invent well under pressure. Conversely, we stagnate | | | when caution prevails. -- Buzz Aldrin | ------------------------------ Date: 2 Jan 91 06:45:03 GMT From: swrinde!mips!news.cs.indiana.edu!msi.umn.edu!cs.umn.edu!kksys!orbit!pnet51!schaper@ucsd.edu (S Schaper) Subject: Re: Recent Newsstand Magazine Articles This is one case where I definitely agree with NASA. It seems clear that the crew survived the explosion, and may well have understood what was going on, and that they would not survive impact, or drowning. The conversations, etc would be extremely distressing to the families. And to many other people as well. ************************************************************************** Zeitgeist Busters! UUCP: {amdahl!bungia, uunet!rosevax, chinet, killer}!orbit!pnet51!schaper ARPA: crash!orbit!pnet51!schaper@nosc.mil INET: schaper@pnet51.cts.com ------------------------------ Date: 3 Jan 91 18:52:20 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 01/03/91 (Forwarded) Headline News Internal Communications Branch (P-2) NASA Headquarters Thursday, January 3, 1991 Audio Service: 202 / 755-1788 This is NASA Headline News for Thursday, January 3, 1991 The House Committee on Science, Space and Technology convened this morning to hear testimony by the chairman of the Advisory Committee on the Future of the U.S. Space Program, Norman Augustine, and the panel's vice chairman, Laurel L. Wilkening. The chairman's opening remarks outlined the basic findings of the Committee and its five basic goals: A balanced space program predicated on space science; a mission to planet Earth; a mission from planet Earth, a strong effort in maintaining the technology base; and a robust space transportation system. * * * * * * * * * * * * * * * * * * * * * * * * * * At Venus, the Magellan spacecraft continues to perform normally on its survey mission of Earth's sister planet. Magellan has orbited Venus about 700 times and data from 677 orbits have been successfully received on Earth. Problems with tape recorder A aboard Magellan before the holidays led controllers to implement a plan using only the B- side data recorder. With one recorder, each image swath now has three small gaps in it, as the recorder switches from track to track. A few bad frames still occur with the B-side recorder, however the rate of bad image frames has dropped, and the amount of usable data has significantly increased with the new strategy. Commands sent to the spacecraft during the holidays were performed without incident, and a new command sequence will be sent to Magellan tomorrow. * * * * * * * * * * * * * * * * * * * * * * At Kennedy Space Center, technicians are now working on all three orbiters, preparing them for their respective missions. In the Vehicle Assembly Building, workers have begun preparations for post-flight inspections of Columbia's aft engine compartment and crew module, and booster stacking for STS-37 continues. Discovery power up continues in the Orbiter Processing Facility, and installation of the Forward Reaction Control System is scheduled to begin tonight. Installation of the number three APU on Atlantis continues, and the shuttle's robot arm is scheduled to be installed this weekend. Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. **indicates a live program. Thursday, 1/3/91 12:30 pm NASA Update -- The Year in Review, Part 2 1:00 pm Testimony of the chairman of the Advisory Committee on the Future of the U.S. Space Program before the House Committee on Science, Space, and Technology (Recorded playback of the morning's live Program) 6:00 pm NASA Update -- The Year in Review, Part 2, followed by: Testimony of the chairman of the Advisory Committee on the Future of the U.S. Space Program before the House Committee on Science, Space, and Technology (Recorded playback of the mornings live Program) Friday, 1/4/91 No scheduled programming All events and times may change without notice. This report is filed daily, Monday through Friday, at 12:00 pm, EST. It is a service of Internal Communications Branch at NASA Headquarters. Contact: CREDMOND on NASAmail or at 202/453-8425. NASA Select TV: Satcom F2R, Transponder 13, C-Band, 72 degrees West Longitude, Audio 6.8, Frequency 3960 MHz. ------------------------------ Date: Wed, 02 Jan 91 17:08:18 AST To: MIRANDA@GRACIE.GRDL.NOAA.GOV From: LANG%unb.ca@unb.ca(Richard@UNBMVS1.csd.unb.ca Langley) Subject: Launch of Navstar GPS II-10 and Shutdown of I-6 The 10th Navstar GPS Block II satellite, PRN 23, was launched on 26 November 1990 into the E-plane, and was made available on 10 December. Satellite I-6,PRN 9, has been set unusable since 11 December 1990. The updated Navstar GPS Constellation Status table given below reflects these events. Navstar GPS Constellation Status (91-01-02) Blk NASA Orbit II PRN Internat. Catalog Plane Launch Seq SVN Code ID Number Pos'n Date Clock Comment -------------------------------------------------------------------------------- Block I 1 4 1978-020A 10684 78-02-22 Not usable since 85-07 2 7 1978-047A 10893 78-05-13 Not usable since 85-09 3 6 1978-093A 11054 A-3 78-10-06 Rb 4 8 1978-112A 11141 78-12-10 L-band signals turned off 89-10-14 5 5 1980-011A 11690 80-02-09 Not usable since 84-05 6 9 1980-032A 11783 A-2 80-04-26 Rb Operating on 2nd Rb clock; set unusable 90-12-11 7 81-12-18 Launch failure 8 11 1983-072A 14189 C-3 83-07-14 Cs 9 13 1984-059A 15039 C-1 84-06-13 Cs 10 12 1984-097A 15271 A-1 84-09-08 Cs 11 3 1985-093A 16129 C-4 85-10-09 Rb operating on Rb clock without temp. control Block II II-1 14 14 1989-013A 19802 E-1 89-02-14 Cs Became available 89-04-15 II-2 13 2 1989-044A 20061 B-3 89-06-10 Cs Became available 89-08-10 II-3 16 16 1989-064A 20185 E-3 89-08-18 Rb Became available 89-10-14 II-4 19 19 1989-085A 20302 A-4 89-10-21 Cs Became available 89-11-23 II-5 17 17 1989-097A 20361 D-3 89-12-11 Cs L-band signals enabled 90-01-06 II-6 18 18 1990-008A 20452 F-3 90-01-24 Cs Became available 90-02-14 22:26 UT II-7 20 20 1990-025A 20533 B-2 90-03-26 Cs Became available 90-04-18 23:13 UT II-8 21 21 1990-068A 20724 E-2 90-08-02 Cs Became available 90-08-22 15:00 UT II-9 15 15 1990-088A 20830 D-2 90-10-01 Cs Became available 90-10-15 00:39 UT II-10 23 23 1990-103A 20959 E-4 90-11-26 Cs Became available 90-12-10 23:45 UT Notes 1. NASA Catalog Number is also known as NORAD or U.S. Space Command object number. 2. No orbital plane position = satellite no longer operational. 3. Clock: Rb = Rubidium; Cs = Cesium 4. PRN 16 is scheduled to switch to a Cs clock early in 1991. ================================================================================ Richard B. Langley BITnet: LANG@UNB.CA or SE@UNB.CA Geodetic Research Laboratory Phone: (506) 453-5142 Dept. of Surveying Engineering Telex: 014-46202 University of New Brunswick FAX: (506) 453-4943 Fredericton, N.B., Canada E3B 5A3 ================================================================================ ------------------------------ Date: 2 Jan 91 06:45:02 GMT From: zaphod.mps.ohio-state.edu!mips!news.cs.indiana.edu!msi.umn.edu!cs.umn.edu!kksys!orbit!pnet51!schaper@tut.cis.ohio-state.edu (S Schaper) Subject: Re: Interstellar travel Clearly a Pliestocene civilization has already depleated the local fuel stores. :-) ************************************************************************** Zeitgeist Busters! UUCP: {amdahl!bungia, uunet!rosevax, chinet, killer}!orbit!pnet51!schaper ARPA: crash!orbit!pnet51!schaper@nosc.mil INET: schaper@pnet51.cts.com ------------------------------ End of SPACE Digest V13 #022 *******************