Date: Sat, 24 Apr 93 05:11:27 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #484 To: Space Digest Readers Precedence: bulk Space Digest Sat, 24 Apr 93 Volume 16 : Issue 484 Today's Topics: Command Loss Timer (Re: Galileo Update - 04/22/93) Eco-Freaks forcing Space Mining. JPL's VLBI Project Meets with International Space Agencies New planet/Kuiper object found? PLANETS STILL: IMAGES ORBIT BY ETHER TWIST SIRTF Mission is Still Alive Stephen Hawking Tours JPL Sunrise/ sunset times Vandalizing the sky. Why DC-1 will be the way of the future. Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: Fri, 23 Apr 1993 16:08:08 GMT From: fred j mccall 575-3539 Subject: Command Loss Timer (Re: Galileo Update - 04/22/93) Newsgroups: sci.space,sci.astro,alt.sci.planetary In <1993Apr23.103038.27467@bnr.ca> agc@bmdhh286.bnr.ca (Alan Carter) writes: >In article <22APR199323003578@kelvin.jpl.nasa.gov>, baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >|> 3. On April 19, a NO-OP command was sent to reset the command loss timer to >|> 264 hours, its planned value during this mission phase. >This activity is regularly reported in Ron's interesting posts. Could >someone explain what the Command Loss Timer is? The Command Loss Timer is a timer that does just what its name says; it indicates to the probe that it has lost its data link for receiving commands. Upon expiration of the Command Loss Timer, I believe the probe starts a 'search for Earth' sequence (involving antenna pointing and attitude changes which consume fuel) to try to reestablish communications. No-ops are sent periodically through those periods when there are no real commands to be sent, just so the probe knows that we haven't forgotten about it. Hope that's clear enough to be comprehensible. -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Ames Dryden ------------------------------------------------------------------------------ Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. ------------------------------ Date: 23 Apr 1993 12:46:35 -0400 From: Pat Subject: Eco-Freaks forcing Space Mining. Newsgroups: sci.space Organization: Express Access Online Communications USA Lines: 26 Message-Id: <1r96hb$kbi@access.digex.net> References: <1993Apr21.212202.1@aurora.alaska.edu> <1993Apr22.134642.13538@lambda.msfc.nasa.gov> <1r6b7v$ec5@access.digex.net> <1993Apr23.001718.1@aurora.alaska.edu> Nntp-Posting-Host: access.digex.net Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU In article <1993Apr23.001718.1@aurora.alaska.edu> nsmca@aurora.alaska.edu writes: >In article <1r6b7v$ec5@access.digex.net>, prb@access.digex.com (Pat) writes: >> Besides this was the same line of horse puckey the mining companies claimed >> when they were told to pay for restoring land after strip mining. >=== >I aint talking the large or even the "mining companies" I am talking the small >miners, the people who have themselves and a few employees (if at all).The >people who go out every year and set up thier sluice box, and such and do >mining the semi-old fashion way.. (okay they use modern methods toa point). Lot's of these small miners are no longer miners. THey are people living rent free on Federal land, under the claim of being a miner. The facts are many of these people do not sustaint heir income from mining, do not often even live their full time, and do fotentimes do a fair bit of environmental damage. These minign statutes were created inthe 1830's-1870's when the west was uninhabited and were designed to bring people into the frontier. Times change people change. DEAL. you don't have a constitutional right to live off the same industry forever. Anyone who claims the have a right to their job in particular, is spouting nonsense. THis has been a long term federal welfare program, that has outlived it's usefulness. pat ------------------------------ Date: 23 Apr 1993 17:38 UT From: Ron Baalke Subject: JPL's VLBI Project Meets with International Space Agencies Newsgroups: sci.space,sci.astro From the "JPL Universe" April 23, 1993 VLBI project meets with international space agencies By Ed McNevin Members of JPL's Space Very Long Baseline Interferometry (VLBI) project team recently concluded a week-long series of meetings with officials from Russia and Japan. The meetings were part of "Space VLBI Week" held at JPL in early March and were intended to maintain cooperation between international space agencies participating in the development of the U.S. Space VLBI Project, a recently approved JPL flight project set for launch in 1995. U.S. Space VLBI will utilize two Earth-orbiting spacecraft -- the Japanese VSOP (VLBI Space Observing Program) satellite with its 8-meter radio telescope, and a Russian RADIOASTRON 10-meter satellite. Both spacecraft will team up with ground-based radio telescopes located around the world to create a radio telescope network that astronomers hope will expand radio telescope observing power by a factor of 10. Japan's VSOP satellite will use a limited six-hour orbit to conduct imaging science, while the Russian RADIOASTRON spacecraft will exploit a larger, 28-hour Earth orbit to conduct exploratory radio astronomy. Each satellite will point at a source target for roughly 24 hours, while approximately 20 ground-based radio telescopes will simultaneously point at the same source object while within view on Earth. According to Dr. Joel Smith, JPL's project manager for the U.S. Space VLBI, meetings like those held at JPL will permit Japan and Russia, who have little previous experience in radio interferometry, to establish working relationships with the radio astronomy communities that will be vital during the complex observations required by the Space VLBI project. "One of our main activities is developing the methodology for international coordination, because the two spacecraft simultaneously rely on the corresponding tracking stations while using the ground-based radio telescopes to observe the same celestial objects," said Smith. Three new tracking antennas are being built at DSN facilities and other three other tracking facilities located in Japan, Russia and Green Bank, W.Va. This global network of ground-based radio telescopes will use precision clocks and high-speed recorders to collect observation data and forward the information to a correlator located at the National Radio Astronomy Observatory in Socorro, N.M. The correlator will combine and process data, then make it available to mission investigators in Moscow, Tokyo, and JPL via electronic mail. Smith is optimistic that the massive radio telescope created by the Space VLBI network will provide radio astronomers with better resolution than has ever been achieved before by ground-based radio telescopes, allowing astronomers to take a closer look at distant objects in space. "There is a long history of radio astronomy using ground-based telescopes," said Smith. "What we intend to do is to extend radio astronomy into Earth orbit. Our goal is to look deeper into the cores of galactic nuclei, quasars and other active radio sources to understand what drives those things we have seen so far with radio astronomy." Smith noted that if one examines "the active galactic nuclei, you'll find jets appearing to spew at speeds greater than light, and at energy levels that are millions of times greater than you would expect." He said some astronomers believe that black holes may be located in the cores of these galaxies, and that they may fuel the jets. Smith hopes that "by using Space VLBI to look further into the cores, this theory may be supported or disproved." Russian space-flight hardware, including transponders and transmitters, are now being tested in the United States, and Japanese hardware is scheduled to arrive for testing later this year. Analysis of this hardware will permit U.S. scientists and engineers to understand how to modify the high-speed VLBA Correlator operating at the NRAO in order to accommodate the odd data patterns that will originate from the more than 20 ground-based radio telescopes involved in Space VLBI. Smith is particularly pleased that meetings with the Japanese and Russian space agency officials -- like those held at JPL in March -- have proceeded smoothly. Yet he knows that the political uncertainty in Russia could jeopardize that country's participation in the project. "Nothing is ever smooth," he said, "but the Russians have been incredibly open with us. We always anticipated some likelihood that we will not succeed because of political factors beyond our control, yet there tends to be a way of keeping these things going, because scientists on both sides are trying hard, and people recognize the value of cooperation at this level." Smith points out that the Japanese space agency has more at stake than just fulfilling an international commitment to a science mission. "The Japanese have been extremely cooperative, since international cooperation is essential to their science mission," he said. But Smith also noted that Japanese space agency officials look at the U.S. Space VLBI mission as an opportunity to showcase the technology involved with VSOP spacecraft, and their highly regarded Mach V launch vehicle. Yet regardless of the risks involved in undertaking such an ambitious project, JPL's Smith is satisfied that planning for the Space VLBI Project is beyond the significant financial and political hurdles that otherwise might threaten the project. "Fortunately, we have the virtue of having two partners, and if either falls out, we would still have something with the other. By themselves, both spacecraft are independent, scientifically exciting missions." ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and |_____|/ |_|/ |_____|/ | part vegetable. ------------------------------ Date: Fri, 23 Apr 1993 17:06:52 GMT From: James Davis Nicoll Subject: New planet/Kuiper object found? Newsgroups: sci.space If the new Kuiper belt object *is* called 'Karla', the next one should be called 'Smiley'. James Nicoll ------------------------------ Date: Fri, 23 Apr 1993 16:54:59 GMT From: Jack Coyote Subject: PLANETS STILL: IMAGES ORBIT BY ETHER TWIST Newsgroups: sci.space,sci.astro In sci.astro, dmcaloon@tuba.calpoly.edu (David McAloon) writes: [ a nearly perfect parody -- needed more random CAPS] Thanks for the chuckle. (I loved the bit about relevance to people starving in Somalia!) To those who've taken this seriously, READ THE NAME! (aloud) -- Thank you, thank you, I'll be here all week. Enjoy the buffet! ------------------------------ Date: 23 Apr 1993 17:30 UT From: Ron Baalke Subject: SIRTF Mission is Still Alive Newsgroups: sci.space,sci.astro From the "JPL Universe" April 23, 1993 SIRTF is still very much in business By Mark Whalen In these times of extra-tight NASA budgets, the very survival of a number of missions has been uncertain. But thanks to major design refinements implemented in recent months, JPL's Space Infrared Telescope Facility (SIRTF) -- a major project considered to be in trouble a couple of years ago -- is "alive and well," according to Project Scientist Michael Werner. A lighter spacecraft, revised orbit and shorter mission have added up to a less expensive project with "tremendous scientific power" and a bright future, said Werner. Designed as a follow-up to the highly successful Infrared Astronomical Satellite (IRAS) and Cosmic Background Explorer (COBE) missions, SIRTF -- a cryogenically cooled observatory for infrared astronomy from space -- is scheduled for launch in 2000 or 2001 if plans proceed as scheduled. IRAS' pioneering work in space-based infrared astronomy 10 years ago allowed astronomers to view the Milky Way as never before and revealed, among other things, 60,000 galaxies and 25 comets. It provided a sky survey 1,000 times more sensitive than any previously available from ground-based observations. COBE has measured the infrared and microwave background radiation on large angular scales, and revealed new facts about the early universe. But to illuminate SIRTF's potential, Jim Evans, JPL's manager of Astrophysics and Fundamental Physics Pre-Projects, recently said that the project is "1,000 to 1 million times more capable than IRAS," based on technological advances in infrared detector arrays. However, despite the enormous strides in infrared exploration SIRTF promised, and the fact that it was cited as the highest priority new initiative for all of astronomy in the 1990s (by the National Academy of Sciences), it took a "diet or die" directive from NASA Headquarters last year to keep the project going, according to Werner. The project is now known as Atlas SIRTF, based on the key factor in its new design: The satellite will orbit the sun instead of the Earth, permitting the use of an Atlas rocket launch instead of the formerly proposed and heavier Titan. "The main advantage of the solar orbit is that you can use all of your launch capability for boosting the payload -- you don't have to carry up a second rocket to circularize the orbit," Werner said. The other advantage to a solar orbit, he said, is that "it's in a better thermal environment, away from the heat of the Earth." Additional major changes in SIRTF's redesign include shortening the mission from five to three years and building a spacecraft that is less than half as heavy as in the original plan -- Atlas SIRTF will weigh 2,470 kilograms (5,400 pounds) compared to Titan SIRTF's 5,500 kilograms (12,100 pounds). All of that adds up to "a less stressful launch environment," Werner said, and a cost savings of more than $200 million for the launch, in addition to increased savings in the design of the smaller, less massive spacecraft. Werner said SIRTF's redesign came as a result of Congress' telling NASA "you're trying to do too many things. If you want us to support SIRTF, which is a good project, develop a plan to see how it fits into (NASA's) overall strategy." Shortly thereafter, SIRTF was named as NASA's highest priority "flagship" scientific mission by the interdisciplinary Space Sciences Advisory Committee, in addition to the blessing from the National Academy of Sciences. While the spacecraft and its instruments required descoping to keep the project alive, SIRTF's major scientific contribution always promised to come about from its advanced infrared detector arrays, which will allow images to be developed "tens of thousands of times faster" than before, according to Evans. "Up until a couple of years ago," Werner said, "all infrared astronomy was done with single detectors -- or very small arrays of individually assembled detectors. Since then, the Department of Defense has developed a program to produce arrays of tens or hundreds of thousands of detectors, rather than just a few, and those are very well suited for use on SIRTF." Werner noted that in addition to dealing with budget pressures, Congress is currently watching NASA projects with an eye out for any "technological spinoff." "On that question, I think we have some things to say," he said, "because the detectors we're using are straight off various military developments. Also, SIRTF will be built by the U.S. aerospace industry, and it's a real technological and engineering challenge in addition to being a tremendous scientific project. "SIRTF will be used by the entire astronomical community," Werner added, but the revised three-year mission "puts a premium on observing time. We have to educate the user community and develop a program that involves early surveys and quick turnaround of the data." Werner said the downsizing of the project required a reduction in scope and complexity of SIRTF's three instruments -- the infrared spectrograph, infrared array camera and multiband imaging photometer. However, these reductions will only result in losses of efficiency rather than capability, he said. The project hopes to start a "Phase B" activity in 1995, which will provide a detailed concept for development and design. Building the hardware would begin about two years later. Projected cost estimates, Evans said, are $850 million-$950 million. "I am very optimistic about SIRTF," he said. "It will provide a tremendous return for the investment." Werner added that an additional benefit from the project will be the "enrichment of our intellectual and cultural environment. People on the street are very interested in astronomy ... black holes, the possibility of life on other planets, the origin of the universe ... and those are the kind of questions SIRTF will help answer." ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and |_____|/ |_|/ |_____|/ | part vegetable. ------------------------------ Date: 23 Apr 1993 17:32 UT From: Ron Baalke Subject: Stephen Hawking Tours JPL Newsgroups: sci.space,sci.astro,sci.physics From the "JPL Universe" April 23, 1993 Cosmologist Stephen Hawking tours Lab By Karre Marino Some 15 years after his first visit to JPL, Prof. Stephen Hawking, Lucasian professor of mathematics at Cambridge University and author of "A Brief History of Time," returned to the Lab April 5. On a tour hosted by JPL Chief Scientist Dr. Moustafa Chahine and Merle McKenzie, manager of the International Affairs Office, Hawking visited a variety of facilities, met with Lab Director Dr. Edward Stone and various project scientists and managers, and felt "like royalty," he said. Hawking, whose theories attempt to explain the origin of distant galaxies, black holes and alternate dimensions, wanted to re-visit JPL, he explained, "because while I'm most interested in those things in space that are farther away, I know that here is where the first steps are taken." Hawking, who was accompanied by his family, two graduate students and his aides, began the tour in von Karman Auditorium, as David Evans, deputy assistant Lab director in the Office of Flight Projects, and Dr. Arden Albee, Mars Observer's project scientist, briefed him on current and past flight projects. Voyager was pointed out to him, with special attention paid to a gold plate with a series of engraved images. Should extraterrestrial life stumble upon the spacecraft, Evans noted, they would find a variety of images that would explain something of Earth. The professor asked if we were still communicating with the spacecraft, and Evans affirmed that we are. Using a model of Mars Observer, Albee spent several minutes describing the project and the spacecraft's features. In answer to a question from Hawking, Chahine described a proposed drag-free satellite, but confirmed that at this point, "it's only a concept." Chahine, who had met Hawking at Caltech about five years before, described the professor as "a living miracle of the power of the brain. He's miraculous, and he has such a good sense of humor." The next stop, a demonstration on scientific data visualization in Section 384's Digital Image Animation Lab, entertained and delighted the group, as everyone donned goggles to view 3-D images of Mars. Project Scientist Dr. Eric De Jong showed off the latest data -- a comet that had only recently been discovered in orbit close to Jupiter. Hawking was curious about its composition, and as he was shown how images are developed, he asked several questions on their interpretation. Norman Haynes, ALD, Office of Telecommunications and Data Acquisition, briefed the professor on the Space Flight Operations Facility, and then Hawking spoke with Stone. The day ended with two technical discussions of particular interest to the professor. Technical Group Leader Dr. Frank Estabrook and Senior Research Scientist Hugo Wahlquist described a three-spacecraft gravity wave experiment, currently under way. Then planetary astronomer Dr. Richard Terrile explained the philosophy and plans for extra solar system planetary detection. The Hawking party, which had been visiting Southern California for five weeks, was headquartered at Caltech, and planned to leave for England within a few weeks after the Lab tour. Upon departing, the Cambridge-based scientist promised Chahine that he would return to JPL for another visit. ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and |_____|/ |_|/ |_____|/ | part vegetable. ------------------------------ Date: Fri, 23 Apr 1993 16:20:14 GMT From: Simon Tardell Subject: Sunrise/ sunset times Newsgroups: sci.misc,sci.math,sci.space In <1993Apr21.141824.23536@cbis.ece.drexel.edu> jpw@cbis.ece.drexel.edu (Joseph Wetstein) writes: >Hello. I am looking for a program (or algorithm) that can be used >to compute sunrise and sunset times. >I would appreciate any advice. I once thought it would be easiest fitting a sine to the times. But not. This gave discrepancy of upto six minutes. If you fit a sine series you'll get a very good fit after just three or four terms though. This presumably has to do with the eccentricity of the Earths orbit. -- Simon Tardell, Ff88, simon@nada.kth.se V}ga v{gra cgs! ------------------------------ Date: Fri, 23 Apr 1993 17:05:30 GMT From: "George F. Krumins" Subject: Vandalizing the sky. Newsgroups: sci.astro,sci.space Jeff.Cook@FtCollinsCO.NCR.COM (Jeff Cook) writes: >In article enzo@research.canon.oz.au (Enzo Liguori) writes: >>Now, Space Marketing >>What about light pollution in observations? (I read somewhere else that >>it might even be visible during the day, leave alone at night). >I can't believe that a mile-long billboard would have any significant >effect on the overall sky brightness. Venus is visible during the day, >but nobody complains about that. Besides, it's in LEO, so it would only When I was at the Texas Star Party a few years ago, the sky was so dark that Venus did, indeed, cause light pollution until it set. Even if the billboard were dark it could cause a problem. Imagine observing an object and halfway through your run, your object was occulted! I would guess that most of the people stating positive opinions are not fanatically serious observers. It is so typical that the rights of the minority are extinguished by the wants of the majority, no matter how ridiculous those wants might be. George Krumins -- -------------------------------------------------------------------------------- | George Krumins | | gfk39017@uxa.cso.uiuc.edu | ------------------------------ Date: Fri, 23 Apr 1993 16:04:01 GMT From: fred j mccall 575-3539 Subject: Why DC-1 will be the way of the future. Newsgroups: sci.space In <1r6ub0$mgl@access.digex.net> prb@access.digex.com (Pat) writes: >In article <1993Apr22.164801.7530@julian.uwo.ca> jdnicoll@prism.ccs.uwo.ca (James Davis Nicoll) writes: >> Hmmm. I seem to recall that the attraction of solid state record- >>players and radios in the 1960s wasn't better performance but lower >>per-unit cost than vacuum-tube systems. >> >I don't think so at first, but solid state offered better reliabity, >id bet, and any lower costs would be only after the processes really scaled up. Careful. Making statements about how solid state is (generally) more reliable than analog will get you a nasty follow-up from Tommy Mac or Pat. Wait a minute; you *are* Pat. Pleased to see that you're not suffering from the bugaboos of a small mind. ;-) -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Ames Dryden ------------------------------------------------------------------------------ Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. ------------------------------ End of Space Digest Volume 16 : Issue 484 ------------------------------