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, 16 Jan 91 20:59:30 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 16 Jan 91 20:59:26 -0500 (EST) Subject: SPACE Digest V13 #053 SPACE Digest Volume 13 : Issue 53 Today's Topics: SPACE DIGEST Cameras in 0G, was: Re: MIR Vacation Humanity's Launch Window Re: Fwd: NASA Plans To Redesign Space Station Magellan Update - 01/15/91 Galileo's flyby sheds light on lunar mystery (long) Re: Barium/Lithium altazimuths CRRES 1/14/91 Early Release viewed in Pasadena 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: Mon, 14 Jan 91 12:37 EDT From: APSEY%RCSMPB@gmr.com Subject: SPACE DIGEST I have not received SPACE DIGEST yet this year. Why? Jim Apsey apsey@gmr.com ------------------------------ Date: 14 Jan 91 20:35:50 GMT From: mcsun!ukc!harrier.ukc.ac.uk!hobby.ukc.ac.uk!has@uunet.uu.net (H.A.Shaw) Subject: Cameras in 0G, was: Re: MIR Vacation In article <569@dtg.nsc.com> alan@dtg.nsc.com (Alan Hepburn) writes: >Don't tell me that my camera won't work up there; I have the same camera >that NASA chose for their flights. The Hasselblad was chosen because >it was the only camera that required NO modification for 0G operation. Whats all this about modifications for 0G? I have a reasonably cheap East German camera, a mid range Japanesse 35mm compact, and before them a Kodak Instamatic which I got for my 7th birthday and worked perfectly for over 15 years. I use them the right way up, on their side, facing down for flat coping and even upside down or pointing straight up for buildings and trees from odd angles. I have used them from sea level to 14,000 feet and out of the windows of aircraft, speedboats and rally cars. I even changed the film in a rally car, doing 80 mph across the ploughed fields of France at 1am. I have lens, both automatic and manual from 28mm to 1000mm, motor winds, flashguns etc. I have around 20,000 slides in my current collection and I've never knowingly lost a shot because of gravity. What difference does gravity make? Maybe it makes using a tripod a little more tricky :-) This sounds like the $483 space rated hammer again to me! >Alan Hepburn "It's what you learn after you know it all >National Semiconductor Corp that counts. >Santa Clara, Ca - John Wooden >mail: alan@spitfire.nsc.com Email: has@ukc.ac.uk | Howard Allan Shaw. | The Unit for Space Science. Phone: +44 227 764000 Extn: 3785 | Room 165, Physics Laboratory, | The University, | Canterbury, England. CT2 7NZ ------------------------------ Date: 14 Jan 91 17:54:22 GMT From: hpfcso!hpfcdc!ajs@hplabs.hpl.hp.com (Alan Silverstein) Subject: Humanity's Launch Window I solicit your comments on the following essay, here or by mail. It is the result of a lifetime of space-interest, recent years of frustration, and six months of consideration. I think it embodies a novel, possibly even frightening, hopefully motivational idea. If the feedback I get is sufficiently positive, I will seek to spread this message by getting the (improved) essay published as widely as possible. The original is troff, with many text enhancements, so it looks a lot better on paper. I put "*" around bold text. After this round of comments, I will make the pre-troff source of the next draft available to anyone who wants a copy to spread the message. Thank you! Humanity's Launch Window Alan Silverstein January 14, 1991 *Five billion years from now*. That's about when the Sun will expand into a red giant star. Its atmosphere will engulf and vaporize the Earth. All of our dreams, inventions, creations, artifacts, and remains will become a mingled gas. Also our pollution, landfills, war machines, inner cities, and petty differences. The thought is both reassuring and humbling. Everything we affect is headed for ultimate oblivion as a hot gas... Unless before then we are able to move off the Earth; move the Earth; change the Sun's life cycle; or make something *really* exciting happen. *Four and a half billion years*. That's about how long it took for self-awareness to appear on the Earth. As far as we know, we are the first Earth species capable of departing the planet. It took over four thousand million years for life on our world to reach this point -- for our ``launch window'' to open. *Many thousands of people, all peacefully cooperating*. That's what it takes to launch a payload from the Earth. Discovery of the New World by Europeans required a few sailing ships. The exploration could be accomplished and the exploitation (ethical or not) begun by perhaps fifty people in one lifetime. A successful space program is at least two orders of magnitude more demanding. *Thirty years*. That's about how long humanity's ``launch window'' has been open. There are wonders beyond comprehension awaiting us beyond our Earth. To achieve a toehold, a foothold, on those riches requires enormous investment. It takes raw materials and the technology to render them. It takes many, many people, at peace with each other in a stable society, wealthy enough to make investments whose return is measured in generations. Our precious Earth is crowded. Our raw materials are being consumed. *Our launch window will close*. *How long do we have?* It is anyone's guess. I think no more than fifty years. Perhaps much less. After that -- no one, no group, will have the resources, the time, the energy, to spare on expanding into space. The Dream might survive, but as an escapist fantasy on a crowded world become a prison. A world of inmates bound by gravity's bars. *Imagine it*. Nine billion years for Earth. An eighty year launch window for humanity. Now *that* is the big picture. Perhaps, in the long run, it is the only perspective that counts. *Now is our species's crux move*. Our one shot at virtually infinite wealth and discovery. We can pursue the Great Adventure. Or we can fritter away our opportunity -- and wake up one day to discover it's too late. We can let our launch window close. *Which do we choose?* ``It has yet to be proven that intelligence has any survival value.'' -- Arthur C. Clarke ------------------------------ Date: 15 Jan 91 18:12:29 GMT From: rochester!sol!yamauchi@louie.udel.edu (Brian Yamauchi) Subject: Re: Fwd: NASA Plans To Redesign Space Station In article <9101151502.AA07365@iti.org> aws@ITI.ORG ("Allen W. Sherzer") writes: >2) The Truss: In particular, building it in orbit. Someone mentioned >that the truss was cut in the latest redesign -- did this refer to >just the dual keel design (which was cut earlier) or the *entire* >truss? One of the designs proposed when Congress mandated the design be evaluated eliminated most of the truss. A small part would be left to hang experiments on and the rest removed. This approach also used smaller modules for building the station. Each module would be self contained and could go up on a single Shuttle flight. A module would be flown up, docked, and ready to go. Hmmm... So where would this design place the solar panels? -- _______________________________________________________________________________ Brian Yamauchi University of Rochester yamauchi@cs.rochester.edu Computer Science Department _______________________________________________________________________________ ------------------------------ Date: 15 Jan 91 19:34:19 GMT From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@bloom-beacon.mit.edu (Ron Baalke) Subject: Magellan Update - 01/15/91 MAGELLAN STATUS REPORT January 15, 1991 The Magellan spacecraft and its radar system continue to perform nominally. All STARCALS (star calibrations) and DESATS (desaturations) during the past 24 hours were successful. As of 10:49 AM (PST), Magellan has completed 789 mapping orbits. Later today, the spacecraft controllers will send updates of the radar control parameter and mapping quaternion files. There will be no "tweak" of the command sequences. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 14 Jan 91 18:36:48 GMT From: eagle!news@ucbvax.Berkeley.EDU (Ronald E. Graham) Subject: Galileo's flyby sheds light on lunar mystery (long) [The following article was published in the Cleveland Plain Dealer, 01/13/91. It was written by Ron Haybron, associate professor of physics at Cleveland State, in his weekly "Science Notebook." - RG] In these tight-money days, scientists are careful to capitalize on every opportunity to gather any scrap of data that becomes available. For instance, they got a chance to snatch a glance at the back side of the Moon last month as the Galileo spacecraft whizzed by on its long voyage to Jupiter. That Galileo came anywhere near the moon on this trip was strictly an accident: its objective is to investigate Jupiter and some of its satellites, starting in December 1995. But a series of events that began with the loss of the space shuttle Challenger culminated in the close encounter in December [1990], which produced some welcome information about our nearest planetary neighbor. The spacecraft, which carries an orbiter for a prolonged imaging mission and a probe that will parachute into the Jovian atmosphere to monitor conditions there, was carried into an orbit above the Earth's atmosphere by the shuttle Atlantis, from which it was launched. In the original plan, the rocket to propel Galileo toward Jupiter was the Centaur, a LH_2/LO_2-powered "upper stage" that was developed at NASA Lewis Research Center. This powerful engine was originally designed to be put atop a primary booster, such as the Atlas, to carry heavy interplanetary probes, such as the Voyager spacecraft, from low Earth orbit to their distant goal. And it seemed perfect for Galileo. But after the Challenger accident, planners at the Johnson Space Center in Texas decided that putting the Centaur in the cargo bay of a shuttle was too risky. The rocket had not been planned for use on missions with a crew, and even though the Lewis launch team had acquired a lot of experience with Centaur and was confident it could do the job safely [Amen. I was there.], Centaur was replaced with a lower-powered solid-fuel rocket. Such devices are basically large-scale versions of Fourth of July bottle rockets. They are considered much safer than liquid-fueled engines. Once that decision had been made, the short, fast trajectory to Jupiter that had been possible for Galileo when driven by the powerful centaur was now impossible. Instead, planners had to come up with a very complex mission profile involving several flybys of various bodies in the inner part of the solar system. This was necessary to take advantage of the "slingshot effect," in which a spacecraft flies very near a moon or planet, speeds up as it falls toward the larger body, and flies off at a greater speed than it had before the encounter. Such a result, at first glance, seems to violate conservation of energy, but in fact the large body slows down slightly. The slingshot effect has become a routine way of flinging low-powered spacecraft off to the outer reaches of the solar system, but the path for such a maneuver is very long, so such missions are considerably extended, subjecting the spacecraft to prolonged exposure to the hostile environment of space and thus an increased risk of damage by radiation or by tiny meteoroids. Among multiple "loops" around the Sun, Venus, and Earth, Galileo passed very close to the back side of the Moon, providing an opportunity to take a look at that seldom-seen region with the modern imaging tools carried by the spacecraft. Researchers hope they can learn more about the composition of the Moon's far side from this data. This interest is actually a continuation of the work begun in the '60s with the Apollo landings on the lunar surface. Although many regard these brave accomplishments as primarily political, some prominent members of the science community gave the enterprise vigorous support as a way to learn about the Moon's origins. How the Moon was formed has been a controversial topic almost since French astronomer and mathematician Pierre Simone de Laplace [Laplace transforms] proposed at the end of the 18th century his condensation theory of the formation of the solar system. In this picture, the planets "condensed" from a primordial cloud of gas and dust that surrounded the newly-formed Sun. In the swirling mess, particles collided and stuck to form larger pieces, then chunks, then bigger chunks, and finally the planets as we see them today. This explanation for the formation of the planets, including Earth, seems just as suited to the Moon. Isn't it likely that the Moon formed at the same time as the Earth and by the same mechanisms? The data available even before Apollo and the lunar samples returned by Soviet robot probes in the '60s belied this notion. The Moon is less dense than Earth and has a different chemical composition. To explain these differences, some theorists proposed that the Moon had formed in a different part of the pre-planetary nebula, at a different distance from the Sun, where the chemical composition [of the nebula?] would be different. Then it was somehow captured by the Earth. The catch with this picture was finding a way to model the complicated encounters needed for the capture. A third explanation was that early on, Earth broke into two pieces, with the Moon originally a piece of the low-density outer crust of the Earth. This was the popular theory when I was a student - that the cavity occupied by the Pacific Ocean was the hole left by stuff that became the Moon. The Apollo data led to a new vision, that the Moon was formed when the young Earth was hit by a giant meteoroid. We will continue this "Moon-mystery" discussion next week. ------------------------------ Date: 15 Jan 91 00:39:03 GMT From: sdd.hp.com!zaphod!caen!umich!sharkey!cfctech!norm@ucsd.edu (Norman J. Meluch) Subject: Re: Barium/Lithium altazimuths sterner@warper.jhuapl.edu (Ray Sterner) writes: {R} This is to be a large barium cloud or lithium. Tables for two alternate {R} times are given below. From hotline information as of 1:08 pm EST. {R} Note: the alternate release times below are actually the start and end {R} times of a time window. That may mean that the release could occur {R} anytime within the window. Call the hotline to get the latest release {R} time. As of 7:15 EST there are 5 exact times available for possible releases. The time of the first small barium release has been decided upon. EST Long Deg W Lat Deg N Height km +-------------+----------+---------+---------+ |Jan. 14 23:11| 97.7 | 17.9 | 14800| +-------------+----------+---------+---------+ The second attempted release will be another large lithium (difficult to see so they say :-) release at any of the following times: EST Long Deg W Lat Deg N Height km +-------------+----------+---------+---------+ |Jan. 15 02:35| 101.6 | 9.3 | 33400| |Jan. 15 03:05| 104.9 | 8.1 | 33500| |Jan. 15 03:35| 108.1 | 6.8 | 33100| |Jan. 15 04:05| 111.2 | 5.4 | 32000| |Jan. 15 04:35| 114.0 | 3.9 | 30370| +-------------+----------+---------+---------+ Happy viewing. Still overcast here ... grumble. - Norm. P.S. Great updates Ray! Keep 'em coming. Perhaps you could add Detroit? Right now I kind of interpolate between Columbus and Chicago. -- |~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Norman J. Meluch ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| | Mail: norm@cfctech.cfc.com Fax:(313)948-4975 Voice:(313)948-4809 | | Note: The opinions expressed here are in no way to be confused with valid | |_______ideas or corporate policy.____________________________________________| ------------------------------ Date: 14 Jan 91 23:30:31 GMT From: usc!julius.cs.uiuc.edu!zaphod!swrinde!elroy.jpl.nasa.gov!mipl3!shw941@ucsd.edu Subject: CRRES 1/14/91 Early Release viewed in Pasadena We observed the CRRES release at 8:13 p.m. PST in Pasadena, CA., from the balcony at Tom's place. (No thanks to L.A.'s lights---fortunately it was relatively clear). The release appeared as a grey expanding disk that gained in luminance for about 30-45 seconds and faded rapidly. We were lucky enough to spot the emission early in its release and were able to watch nearly the entire duration. It would have been easy to miss if you weren't lucky enough to spot it early. The azimuth and elevation data posted were particularly helpful. We anticipate catching a glimpse of the next release, hopefully it will be before we have to go catch some Z's. Stephen Watson Tom Kelly Jet Propulsion Laboratory Pasadena, CA ------------------------------ End of SPACE Digest V13 #053 *******************