Aucbvax.4152 fa.space utzoo!decvax!ucbvax!space Thu Oct 1 04:19:09 1981 SPACE Digest V2 #1 >From OTA@SU-AI Thu Oct 1 04:08:42 1981 SPACE Digest Volume 2 : Issue 1 Today's Topics: Administrivia Down to the wire with Halley - M. Mitchell Waldrop article in SCIENCE Sen. Proxmire Soviets reenter the manned space business A second reverberating gamma ray burst discovered Where are They?? Anybody out there?? ---------------------------------------------------------------------- Date: 30 Sep 1981 1229-PDT From: Ted Anderson Subject: Administrivia To: space at MIT-MC In case you were wondering what the reason for the change from volume one to volume two was, it is the occasion of the fiscal new year. Happy New Year! In an effort to dampen the excitement of the start of the new fiscal year, the perversity of nature (AKA Murphy's Laws) have conspired to cause many people (mostly on MC, I think) to miss the last digest of volume one. This is issue 204. So if you missed V1 #204 let me know and I will mail you a copy. In case you don't keep close track of the issue numbers this digest contained an unusually large number of messages mostly about Life in the Universe. Also a message from Dietz comparing 1micro-arc-second to the angle subtended by an atom held at arms length (wow). Anyway if you missed this one let me know. ------------------------------ Date: 30 Sep 1981 1212-PDT From: Bob Amsler Subject: Down to the wire with Halley - M. Mitchell Waldrop article in SCIENCE To: space at MIT-MC Down to the Wire with Halley (SCIENCE 2 October 1981, V.214,No.4516 p.35) (by M.Mitchell Waldrop) Given the air of fiscal austerity in Washington these days the odds of the Regan Administration's financing a $300 million spacecraft to fly by Halley's comet look slimmer than ever. But until the Administration actually says "No," the space science community is going all out to win approval for the mission. The answer will have to come within the next few weeks. At Jet Propulsion Laboratory in Pasadena, California, planning and design work for the mission is well along, but the schedule is very tight, says project manager Raymond L. Heacock. If the spacecraft is to meet the comet in 1986, it must be launched in the summer of 1985, which means that JPL must start letting contracts no later than next January. This in turn, will be possible only if the Halley mission is included as a new start in NASA's fiscal year 1983 budget, which is being drawn up now. Laurence Soderblom of the U.S. Geologic Survey, chairman of NASA's Space Science Advisory Committee, voices a widespread frustration in the space science community: "It's absolutely insidious, crazy, tragic that we ever got ourselves into a position where we can't do a Halley mission." But in fact, a big part of the problem is that NASA headquarters has never really pushed for Halley. With the space science budget being squeezed every year by the immense cost of the space shuttle, agency officials have been more concerned about preserving such high priority missions as the Galileo orbiter/probe mission to Jupiter and the Venus Orbiting Imaging Radar. Proponents of a Halley mission counter that the comet represents a once-in-a-lifetime opportunity: no other young, active comet has an orbit that is predictable enough for planning a mission. These are the kind of comets that are thought to retain pristine material from the formation of the solar system, and whose dynamics are most interesting. Proponents have also stressed national prestige. The European Space Agency is going to Halley with its "Giotto" spacecraft. The Japanese are going. The Russians are going. So why aren't we going? Besides, they say, the United States has a big lead in navigation and imaging technology. Its close-ups of the comet, the best by far, would give the country a public relations coup on a par with the Voyager missions. (In fact, without such images most people will probably be disappointed in Halley. On this trip its most spectacular displays will occur on the far side of the sun from the earth.) During the recent Voyager 2 encounter with Saturn, JPL director Bruce C. Murray forcefully argued the case for Halley to presidential advisor Edwin Meese and NASA administrator James M. Beggs. Not surprisingly, Meese and Beggs have remained noncommittal, pending submission of NASA's budget proposal. But presidential science advisor George A. Keyworth is interested in the mission, and has asked NASA to prepare a list of options for how it might be done. The space agency's reply is expected to include the following: * JPL's $300 million "baseline" mission. During the 60-day "observatory phase" before encounter the spacecraft would monitor the comet's development with some 3000 long-distance images. During the 3-hour "encounter phase" it would attempt to image the kilometer-sized nucleus. It would also perform in situ measurements of the comet's composition and its particle and field environment. * A somewhat less expensive imaging/sample-return mission. This version is attractive, says Jeffrey D. Rosendhal, deputy head of NASA's Office of Space Science, because it would compliment the other three missions. It would retain the observatory and encounter phase imaging, which is unique, while dropping the in situ experiments that duplicate those planned for ESA's Giotto. The dramatic idea of a sample return came up only last June, very late in the game, says Rosendhal. The spacecraft would capture a few milligrams of comet material on what is esentially a sticky surface, then proceed on a trajectory that would carry it back to earth some 5 years later. Unfortunately, he adds, the sample-return technology is new, poorly understood, and risky. * A swing by Halley with the Galileo spacecraft as the latter heads toward Jupiter. This is the least attractive option, says Rosendhal. It would mean sending Galileo on a long, slow loop around the sun, with a several-year delay in its arrival at Jupiter. Only long-distance imaging would be possible, and from a bad angle at that. But if the Administration cancels development of the high-thrust Centaur booster, which is required to get Galileo to Jupiter on a more rapid trajectory, this version of the Halley mission might be a way of salvaging something. On the other hand, doing Galileo in this way would add another $300 million to its cost--not far below the $445 million price tag for Centaur, and almost exactly the price of the baseline Halley mission. -- M.Mitchell Waldrop. ------------------------------ Date: 29 Sep 1981 19:22:41-PDT From: chico!duke!unc!smb at Berkeley In-real-life: Steven M. Bellovin To: chico!duke!unc!space@Berkeley Subject: Sen. Proxmire That great champion of fiscal responsibility, Sen. Proxmire, made a 16-hour speech that cost -- in lighting, printing, etc. -- $64,000. The ostensible purpose of the speech was to prevent a needed increase in the national debt limit -- which is going to pass anyway. Proxmire is the person primarily response for the demise of SETI. ------------------------------ Date: 30 Sep 1981 1350-PDT From: Ted Anderson Subject: Soviets reenter the manned space business To: space at MIT-MC n536 0237 30 Sep 81 BC-SPACE-09-30 EDITORS: The following is from the London Telegraph and is for use only in the United States and Canada. By Adrian Berry Daily Telegraph, London (Field News Service) LONDON - Four months after announcing the end of all manned space flights until further notice, the Soviet Union has reversed its position and started preparing for new flights. The earlier decision to halt manned space missions was taken almost immediately after Easter's maiden flight of the American space shuttle, which the Russians claim is a military threat to them. Tuesday's announcement, reported in Pravda, that the space flight control center near Moscow is being re-equipped, suggests that the Russians appear to have recovered from their initial panic. They are likely soon to launch a new manned mission toward the Salyut 6 space station, which Wednesday begins a fifth year in orbit, having circled the Earth more than 25,000 times. Salyut 6, originally designed for a working life of only 18 months, has been visited by 16 crews, including eight non-Russian cosmonauts from Soviet-bloc countries. The space station will be kept in orbit ''as long as the designers require,'' the newspaper said Tuesday. Planners envisaged further space stations, some of them equipped with powerful telescopes for probing deeper into the universe. And others are likely to have on board instruments of espionage which will probe more deeply into Western defenses. END nyt-09-30-81 0538edt *************** ------------------------------ Date: 30 Sep 1981 1355-PDT From: Ted Anderson Subject: A second reverberating gamma ray burst discovered To: space at MIT-MC n009 0707 30 Sep 81 BC-GAMMA By WALTER SULLIVAN c. 1981 N.Y. Times News Service NEW YORK - Examination of a backlog of recordings made in earth orbit four years ago by the first High Energy Astronomy Observatory has revealed a burst of gamma rays indicating a catastrophic event far out in space, though how far and in what direction remain unknown. The burst was followed by a half minute of 4.2-second reverberations, suggesting its probable association with a superdense neutron star rotating at that rate. Only one other such reverberating gamma ray burst has been recorded, on March 5, 1979. The newly discovered event was detected on Oct. 29, 1977. The 1979 burst was detected by nine spacecraft scattered around the solar system. By comparing precise arrival times of the burst at each of them, it was possible to determine that it came from the direction of the Large Magellanic Cloud, a small galaxy of stars about 200,000 light years away, not far from the outer fringes of the Milky Way. If the source was that far away, within seconds it must have emitted as much energy as all the stars of the Milky Way combined. Many astronomers believe the source was a neutron star within that star cloud. A neutron star is formed when a large star exhausts its nuclear fuel, cools and collapses into an object of extremely small size, high density and rapid rotation. The newly recognized event was recorded by X-ray detectors placed on the orbiting observatory by the Naval Research Laboratory under the direction of Dr. Herbert Friedman. The detectors were able to record the burst because, while it was primarily in gamma rays, it overlapped the X-ray spectrum. The rays were too weak for recording by other spacecraft. Hence the direction of the source has not been determined. The suddenness and violence of the 1979 event were difficult to explain. As noted last week by Friedman, it soared to full power in only 12-hundredths of a second. In the next three minutes it tapered off, reverberating at an eight-second rate. One suggested explanation was that a comet fell on a neutron star rotating every eight seconds. Another was that an asteroid fell on the star. About 60,000 miles out, the asteroid would have begun to disintegrate under the influence of the neutron star's extreme gravity, stretching into a long trail of debris. This debris would have encircled and fallen on the star, approaching the speed of light and, in one-billionth of a second, becoming heated to two billion degrees Fahrenheit. This could have generated the sharp pulse of gamma rays. The newly found, but earlier, burst, Friedman said, does not fit this model. The two-second time required for the pulse to reach full power was not compatible with an almost instantaneous impact. One possibility, he added, might be that material that had accumulated in orbit around the star fell on it when perturbed in some manner. Another explanation would be sudden contraction or some other form of extremely massive transformation within the star. nyt-09-30-81 1008edt *************** ota - I should note that I went to a talk given by Edward Teller on this subject and he suggested that the March 5, 1979 event was a neutron star / asteroid (or planet) collision. Note, however, that such a "collision" would be more aptly described as a neutron star puncturing the planet(esimal) and the planet very shortly afterwards exploding. ------------------------------ Date: 1 October 1981 00:14 edt From: Schauble.Multics at MIT-Multics Subject: Where are They?? To: space at MIT-AI Suppose every civilization has its share of Proxmires. In fact, suppose that evolution tends to create Proxmires. Then most of not all civilizations would not be exploring for the same reason we are not. They're Proxmired down. Gad, what a horrible thought. Paul ------------------------------ Date: 1 October 1981 06:02-EDT From: Robert Elton Maas Subject: Anybody out there?? To: TAW at SU-AI cc: SPACE at MIT-MC Proxmire's reason for canceling SETI is idiotic. Of course we don't expect meaningful duplex communication with a civilization 1000 light-years away (thus 2000-year turnaround time for each communication interchange). But that isn't the main goal of SETI, it's finding out if there is anybody out there in the first place! Getting that info would be VERY IMPORTANT!! (It's hard to imagine anything more important.) Maybe he has good reasons for canceling SETI, but the infeasibility of meaningful duplex communication isn't one of them. ------------------------------ End of SPACE Digest ******************* ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.