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, 18 Apr 91 01:39:16 -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, 18 Apr 91 01:39:11 -0400 (EDT) Subject: SPACE Digest V13 #420 SPACE Digest Volume 13 : Issue 420 Today's Topics: NASA Headline News for 04/17/91 (Forwarded) Re: Fred on the Moon Re: The first VOSTOK in space Re: NASA & Executive Branch Re: Earth/Moon formation solar sails 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: 17 Apr 91 17:31:46 GMT From: usenet@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 04/17/91 (Forwarded) Headline News Internal Communications Branch (P-2) NASA Headquarters Wednesday, April 17, 1991 Audio Service: 202 / 755-1788 This is NASA Headline News for Wednesday, April 17, 1991 . . . Atlantis made it as far as Columbus, Mississippi, yesterday on the return flight from California following its STS-37 landing. Because of its late departure from Edwards Air Force Base, the 747 shuttle carrier aircraft crew couldn't refuel in San Antonio and make it to the Shuttle Landing Facility during the allotted daylight period. Instead, they opted to lay over at Columbus Air Force Base, and are expecting to leave this morning for Kennedy Space Center. There are some weather concerns for the flight path near the Mississippi-Georgia border, thunderstorms mostly. However, the 747 crew expects to have Atlantis back at Kennedy by early afternoon. * * * * * * * * * * * * * * * * Goddard Space Flight Center flight controllers report that instrument turn-on began yesterday on the Gamma Ray Observatory. At 11:29 am yesterday, the Oriented Scintillation Spectrometer Experiment successfully detected charged particles as the spacecraft flew the South Atlantic anomaly, a positive indication that the OSSE instrument is alive and well. Science operations with GRO are expected to begin the third week of May. * * * * * * * * * * * * * * * * The Stennis Space Center reports that nearly 2,300 guests toured its visitor center last week. The center also notes that its Early Education Monday, an innovative educational program for grade school children, was conducted for 137 students from three schools in Picayune and Kosciusko, Mississippi, and Lacombe, Louisiana. * * * * * * * * * * * * * * * * NASA yesterday issued a request for proposals to establish six Regional Technology Transfer Centers to replace the ten Industrial Applications Centers, whose contract expires this year. This restructuring is intended to upgrade and revitalize the current technology utilization network and to broaden its geographical coverage. The new program also expects to forge new partnerships with state and local government technology transfer centers and to establish close ties with the NASA Centers for the Commercial Development of Space in their respective regions. * * * * * * * * * * * * * * * * Marshall Space Flight Center commemorates the 10th anniversary of the first flight of the shuttle this Friday with a special luncheon at the Redstone Arsenal Officer's Club. Honored at the luncheon will be John Young and Robert Crippen, commander and pilot, respectively, of the shuttle's pioneer mission -- STS-1. Also honored will be individuals from Marshall who, at that time, played a significant role in enabling Columbia to take that historic first step, including then-Center Director Bill Lucas, then-Center Deputy Director Jack Lee, then-Marshall Shuttle Project Manager Bob Lindstrom, then-External Tank Project Manager Jim Odom, and then-Solid Rocket Booster Manager George Hardy. Current Marshall Director Jack Lee will host the luncheon, which starts at 12:00 pm EDT. The press has been invited to cover the luncheon and to interview participants following its close. Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. NASA Select TV is carried on GE Satcom F2R, transponder 13, C-Band, 72 degrees W Long., Audio 6.8, Frequency 3960 MHz. Wednesday, 4/17/91 10:00 am STS-40, Spacelab Life Sciences-1, live Joint Integrated Simulation between Marshall Space Flight Center and Johnson Space Center. Simulation activities continue through 10:00 pm. 1:15 pm Magellan-at-Venus status report and science update live from Jet Propulsion Laboratory. 1:30 pm STS-40 Joint Integrated Simulation activities continue live from Johnson and Marshall centers. Thursday, 4/18/91 8:00 am STS-40, Spacelab Life Sciences-1, live Joint Integrated Simulation between Marshall Space Flight Center and Johnson Space Center. Simulation activities continue through 2:00 pm. Friday, 4/19/91 9:00 am Senate Subcommittee on Science, Technology and Space (Albert Gore, D-Tenn, chairman) hearing on NASA Fiscal Year 1992 budget request and findings of the Advisory Committee on the Future of the U.S. Space Program. NASA Administrator Richard Truly and advisory committee chairman Norman Augustine are witnesses. (This hearing will be covered live at the beginning, and picked up again in progress following the STS-37 briefing. The entire hearing will then be replayed.) 10:00 am STS-37 flight crew post-mission press conference live from Johnson Space Center. Mission commander Steve Nagel, pilot Ken Cameron, and mission specialists Jerry Ross, Jay Apt and Linda Godwin will describe their recent flight and show and narrate video highlights of the mission, which included two spacewalks. 11:00 am Continue live coverage of Senate Subcommittee hearing on NASA budget request. approx. 12:00 pm Replay entire hearing of Senate Subcommittee on NASA Fiscal Year 1992 budget request and advisory committee findings. All events and times may change without notice. This report is filed daily, Monday through Friday, by 12:00 pm, Eastern. It is a service of NASA Headquarters Office of Public Affairs. Contact: CREDMOND on NASAmail or at 202/453-8425. ------------------------------ Date: 16 Apr 91 14:33:58 GMT From: csus.edu!wuarchive!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucdavis.ucdavis.edu (James Davis Nicoll) Subject: Re: Fred on the Moon In article <00946ECB.60A01F20@KING.ENG.UMD.EDU> sysmgr@KING.ENG.UMD.EDU (Doug Mohney) writes: >In article , jpc@fct.unl.pt (Jose Pina Coelho) writes: > >>Other inconveniences: >> Supplies: the energy difference between getting them into low orbit >> and getting them to the moon is quite big. > >Sure, if you use conventional techniques. If you're not in a hurry (gosh, the >moon will still be there), use a combination of solar sails and ion thrusters >to move large cargos. Will take a bit longer, but your fuel costs are much >less. The delta vee required will still be the same. With solar sails, the sun provides the needed energy. With the ion thrusters, you need some sort of power-plant to run the thing. Assuming you don't want to use a chemical powerplant (of course), that means you need either a solar or nuclear power source. Anyone know the current weight to power output of solar and nuclear powerplants? Anyone know the *cost* per unit energy produced of space-rated solar and nuclear powerplants (Assuming no wonderful technological breakthrough in the near future)? A silly question: solar sails look frail. Is there a lowest orbit below which a ss cannot be used because of tides ripping the shroud or air resistance doing likewise? (Material deleted) >> Basicaly the startup cost is dozens/hundreds of times that of LEO. >> Politics, politics, politics ... > >Hundreds? No. Dozens. No. Some factor between 2 and 12 times the cost, yes. How are either of you obtaining your figures for probable cost? James Nicoll ------------------------------ Date: 17 Apr 91 13:09:04 GMT From: agate!bionet!uwm.edu!spool.mu.edu!think.com!hsdndev!cfa203!mcdowell@ucbvax.Berkeley.EDU (Jonathan McDowell) Subject: Re: The first VOSTOK in space From article <3165@ksr.com>, by clj@ksr.com (Chris Jones): > In article <1991Apr17.121648.14304@kcbbs.gen.nz>, George_Muzyka@kcbbs (George Muzyka) writes: >>We all call the first Soviet Vostok manned spacecraft, piloted by Yuri >>Gagarin in April 1961, VOSTOK 1. > When Radio Moscow announced the launch, they referred to it simply as Vostok, > with no number. It wasn't until Vostok 2 that Gagarin's craft was called > Vostok 1. According to Soviet publications on the design of Vostok, there were two test variants Vostok A and Vostok B, with Vostok V (3rd Cyrillic letter) being the piloted variant used by Gagarin. I'm not sure how these variants map on to the Korabl'-Sputnik series, and I'm puzzled by the reference to Gagarin's Vostok as VOstok A3. Interesting. Chris is quite right about the lack of number on Gagarin's Vostok. Even today the Soviets call it Vostok rather than Vostok 1; this is standard Russian practice. Bear in mind that US spacecraft have serial numbers as well as their official names; e.g the Mercury program sequence was Mercury spacecraft 7 (Shepard), 11 (Grissom), 13 (Glenn), 18 (Carpenter), 16 (Schirra) and 20 (Cooper); the A3 designation may be a similar factory serial sequence independent of the flight name sequence. - Jonathan McDowell ------------------------------ Date: 17 Apr 91 13:35:01 GMT From: agate!bionet!uwm.edu!rpi!uupsi!pbs.org!pstinson@ucbvax.Berkeley.EDU Subject: Re: NASA & Executive Branch In article <1020@epiwrl.UUCP>, parker@wrl.epi.com (Alan Parker) writes: > In article <1991Apr15.224632.4668@zoo.toronto.edu>, henry@zoo.toronto.edu > (Henry Spencer) writes: >> Apart from the difficulty of getting such a forthright order out of any >> recent president :-(, alas, no. Checks and balances. The President can >> order NASA to do it, but only Congress can authorize spending money on it. > > > Does it bother others that so many don't seem to understand how our > government works? We shouldn't expect everyone around the world to > understand the limits of a President and the role of Congress; but > certainly every American kid in school is taught about these things. > If Henry has to start telling posters how our government works, then we are > in big trouble. I'm sure few of us can tell him how his works! I AM well aware of what the textbooks say about how our government is supposed to work. Having grown up inside the beltway around the nation's capital I also have a sense for how it actually works. The name of the came is Power and if you can get away with it, you do it. The involvement in Central America, for example, did not go exactly by the book. :-) ------------------------------ Date: 18 Apr 91 03:31:08 GMT From: agate!bionet!uwm.edu!cs.utexas.edu!news-server.csri.toronto.edu!qucis!akerman@ucbvax.Berkeley.EDU (Richard Akerman) Subject: Re: Earth/Moon formation In article <-8bG2m1r1@cs.psu.edu> okunewck@psuvax1.cs.psu.edu (Phil OKunewick) writes: > Several theories had been proposed about the earth/moon formation. >The capture theory is plausable, though highly unlikely. In order for >the moon to have been captured, another massive celestial body would >have had to pass about the same time. Chances of that happenning are >slim; chances of it causing this almost-round orbit are even slimmer. >The orbit also seems to follow the solar plane (unlike pluto); chances >of this occurring are slimmer still. Throw in the moon samples, and >throw this theory out. The earth and moon had to be related in creation. > > The moon-split-off-from-earth theory is more likely, though still >would probably require a celestial body passing. Again, the orbit is >awfully circular, which I suspect is unlikely. But this still doesn't >explain how the earth formed in the first place. Let's be clear here. There is the fission theory, which proposes that the Moon is formed of material spun off the outer layers of the Earth. This theory does not explain where the energy came from to lift these particles off. Then there is the impact-trigger hypothesis, which says that the Moon was formed when Earth was hit by a very lage interplanetary body, blasting material from the Earth's crust and mantle into orbit which then aggregates to form the Moon. This picture ties in well with the hypothesis that the Earth was formed by the binary accretion of swarms of planetesimals (with a runaway phase of rapid growth at the end). You state that you suspect that the high circularity of the Moon's orbit is unlikely. Why? If swarms of particles orbiting the Sun settle into low-eccentricity orbits then why not particles orbiting the Earth? > > My favorite theory is that there was a ring of dust/gas orbiting >the sun which had some eddys in it. The matter in these eddys >collected more matter until they became solid objects (planets and >moons). This allows for the rock to solidify around 4.5 billion years >ago, and assuming that this area of the oribiting dust ring contained >similar matter throughout, it allows for earth and moon rocks to be >the same composition. > > > Now, my skills in geology are strictly ameteur [sic]. Can anybody shed >more evidence/theories on this event? How about why we never see the >back of the moon - what would cause the moon's mass to be that offset? Ok, the usual picture of Solar System formation is that by one process or another we get rocky planetesimals of roughly 10 km diameter forming out of the primordial dust nebula. These planetesimals in turn collide with one another and form larger embryonic planets. A few of these bodies will experience runaway growth at the expense of the others, forming the planets. The currently favoured hypothesis for lunar formation is the impact-trigger hypothesis. It explains a number of things about the composition of the Moon by positing that a large (perhaps Mars-sized) body impacted the Earth at a late stage of planetary evolution. Other theories are the fission theory mentioned above, the co-accretion theory which you favour above and the capture theory. Each of these has some problematic flaws. You see, we know from the Moon rocks that its composition is similar to the Earth's, except it has much less iron. This suggests that the Moon was formed from material similar to the Earth's mantle, except that it is depleted in volatile materials (material such as water that is driven off by heating) and enhanced in refractory elements (elements with high boiling points). This suggested that the lunar material was subjected to strong heating before or as it formed. We can then turn to the formation hypotheses. The fission theory has the problems mentioned before. The co-accretion theory does not explain how the Moon could have formed near the Earth but been depleted in iron. The capture theory does not explain where the Moon could have come from in order to have its low-iron composition. The impact theory seems to account for these problems. The Moon would be depleted in iron because by then the Earth would have undergone differentiation and most of its iron would have sunk to the core. As for the question of the Moon presenting only one face to the Earth, this indicates a bit of confusion. The process by which this occurs is called tidal locking, and is a very common process in the Solar System. In fact, most moons exhibit this same property of presenting only one face to the planet which they orbit. Basically, the Moon is demonstrating synchronous rotation. It is rotating in its orbit in such a way as to always present the same face towards the planet. It has been shown that if the Moon had one axis that was longer than the other, it would tend to want to align this axis so that it always pointed towards the Earth. Since the gravitational field of the Earth causes it to raise a body tide on the Moon that elongates it in one direction, the Moon thus eventually enters this tidal lock with the Earth and we see only one side. All of this material discussed much more clearly than I can manage in most astronomy textbooks. I would recommend Hartmann, W.K. (1989). _Astronomy: The Cosmic Journey_ (Belmont: Wadsworth Publishing Co.) If you want to know about the formation of the Earth (but not the Moon) in detail, try Wetherill, G.W. (1990). Formation of the Earth. _Ann. Rev. Earth Planet. Sci._ 18, 205-256. Richard Akerman Incompetent Physics Graduate Student Akerman@Bill.Phy.QueensU.Ca/ Akerman@QUCdnAst/ "Ban vi" ------------------------------ Date: 16 Apr 91 15:47:10 GMT From: agate!bionet!uwm.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: solar sails In article <1991Apr16.143358.1870@watdragon.waterloo.edu> jdnicoll@watyew.uwaterloo.ca (James Davis Nicoll) writes: > A silly question: solar sails look frail. Is there a lowest orbit >below which a ss cannot be used because of tides ripping the shroud or >air resistance doing likewise? The forces involved are minor compared to the strength of materials, at least for existing sail designs. The major altitude constraint is air drag. Below about 1000km, a conventional solar sail is useless for propulsion because velocity loss from air drag exceeds velocity gain from light pressure. One devious way around this is to punch the sail full of holes on a scale substantially smaller than the wavelength of visible light. The air molecules go straight through, but light still reflects. The sail is also lighter, of course. It's just a lot harder to make... -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of SPACE Digest V13 #420 *******************