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 ; Sat, 15 Dec 1990 01:37:27 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 15 Dec 1990 01:36:53 -0500 (EST) Subject: SPACE Digest V12 #658 SPACE Digest Volume 12 : Issue 658 Today's Topics: Re: Translunar/interplanetary shuttle? Re: Planetary Society Re: ASTRO status at 4/16:00 MET UIT Status for 12/09/90 [1500 CST] (Forwarded) Magellan Update - 12/05/90 Magellan Update - 12/10/90 Magellan Update - 12/04/90 Light years and such Re: Who killed Nuclear Rockets? (was Re: The Next Ten Years In Space) Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 5 Dec 90 17:20:39 GMT From: elroy.jpl.nasa.gov!swrinde!zaphod.mps.ohio-state.edu!samsung!umich!sharkey!teemc!fmeed1!cage@ames.arc.nasa.gov (Russ Cage) Subject: Re: Translunar/interplanetary shuttle? In article <7089.275a4245@abo.fi> mlindroos@abo.fi writes: >As for the problem with the main engines (we've been told here that they are >not restartable), would it be possible to use the extra fuel for the OMS >engines instead...? (my guess is it won't be, anyway). It would be easy to carry extra OMS fuel; it has been proposed before, and I've seen depictions of orbiters with a rack of fuel tanks taking up the back half of the cargo bay. The problem is the low impulse of the OMS engines. To do a trans-lunar injection burn, decelerate into lunar orbit, and burn again to return to earth takes something like a million pounds of OMS fuel. This is about 20 Shuttle payloads worth. Forget the idea of taking a Shuttle orbiter to the moon. It's stupid. Consider that the weight of the Shuttle's wings, tail, engines, landing gear, thrust structure and thermal protection system is probably 130,000 of its 160,000 lbs weight. Eliminate that and you've cut the fuel requirements by 4/5. Then dump the OMS engines and their fuel, and carry a single RL-10 engine burning hydrogen and oxygen. (These ARE restartable, and have never failed to start or restart.) This cuts the required fuel drastically, and the cost of launching it. What you wind up with would be much smaller and cheaper than a Shuttle orbiter for the same payload, and it could be built of off-the-shelf engines and other parts. -- Russ Cage Ford Powertrain Engineering Development Department Work: itivax.iti.org!cfctech!fmeed1!cage (CHATTY MAIL NOT ANSWERED HERE) Home: russ@m-net.ann-arbor.mi.us (All non-business mail) Member: HASA, "S" division. ------------------------------ Date: 9 Dec 90 04:29:04 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@uunet.uu.net (Nick Szabo) Subject: Re: Planetary Society In article <9012072339.AA07773@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >If the Planetary Society wants to produce a consensus statement of people >who hold a particular point of view, then fine. If they want to produce a >statement and claim that it is the general consensus of everyone in the >field, then they shouldn't make a deliberate effort to stack the meeting >with people known to hold a particular point of view. The Planetary Society never claimed the statement covers everybody in the field. They did not "stack" the committee any different than any other committee. The whole issue is a slander against the Planetary Society and an ad hominem attack against this committee's conclusions. It is a sad sight to see a group that includes leaders of our successful exploration of the solar system defamed like this. >My own opinion is that the space station was in need of redesign, particularly >in light of the predicted need for maintenance during assembly. I would also >consider at least the option for use as an assembly point for lunar and >interplanetary craft to be very important. The *concept* of a space station needs redesign. NASA has designed and redesigned dozens of "space stations" since its inception and has only a brief post-Apollo fling, ending in the sands of the Australian outback, to show for it. Maybe it's time we realized the whole aproach is wrong. >Last I heard, the Planetary Society was still pushing for a hideously >costly, crash-priority one-shot manned trip to Mars, mainly to serve >as an inspiration to mankind and generate political goodwill Good grief. Everybody in the planetary science field knows this is just a political ploy to get funding for the stuff that does the real work, the probes. There is no way anybody is going to afford to send people to Mars or anywhere else beyond the Earth system until well after it has been thoroughly explored and mapped. But politics is politics, and if NASA can conjure up space station "customers", the planetary probe folks are entitled to conjure up a macho alternative to war in the cosmos. >and at the >expense of most or all other manned space activity for the forseeable >future. The "manned" program has already chopped up solar system exploration beyond belief, not to mention creating a bloated bureaucracy. I for one will not cry any tears to see it die and the Space Age begin. >I do not consider this a good utilization of human resources in space, I, most explorers, and all successful space commerce companies don't consider throwing around humans in tin cans a good utilization of human resources on Earth. >and since I have read claims that the Planetary Society in its lobbying >tends to imply that *all* its members support the "official" view, I have >avoided joining the Planetary Society in spite of its many excellent >features. Every organization tries to show one face, a consensus opinion. Show me how this is different than other advocacy groups. -- Nick Szabo mystery_alias@sequent.com~ "We live and we learn, or we don't live long" -- Robert A. Heinlein ------------------------------ Date: 9 Dec 90 22:43:23 GMT From: haven!uvaarpa!murdoch!astsun.astro.Virginia.EDU!gsh7w@ames.arc.nasa.gov (Greg Hennessy) Subject: Re: ASTRO status at 4/16:00 MET In article <828@idacrd.UUCP> mac@idacrd.UUCP (Robert McGwier) writes: #Just another example of when you should NOT send a man to do a robot's job. #From the exercises fouling up the stability to lint from uniforms clogging #air intakes, to residue from the huge thrusters (which are only necessary #because it is a huge plane carrying men and the HEAVY life support equipment) #the evidence is overwhelming that good science in astronomy done from #orbit and human presence don't mix. Perhaps you are unaware that for the last four days the astronauts were guiding the instruments because the "robot" was broken? Perhaps you are unaware that this guiding CANNOT be done from the ground because of the round trip travel time? The entire astro concept made no sense #after they spent umpty dumpty million dollars and then refused to fly #it but once. If they fly it again, its cost MIGHT come close to being #justified. Please, by all means, write your congresscritter about ASTRO and write NASA about it. If NASA and congress see public interest, ASTRO WILL fly again. I expect that the images from UIT will be available to the press in early January, and I will try to post FITS images to the net, although I'll have to worry about the bandwidth. #. . . ." We bellyache constantly in the US about the constant advances #by the Japanese and Germans and then do not give adequate support to #doing basic science and basic technology research. It is pitiful. If you think it is pitiful, write to your congresscritter. If you are not part of the solution, you are part of the problem. (Or part of the precipate.) -- -Greg Hennessy, University of Virginia USPS Mail: Astronomy Department, Charlottesville, VA 22903-2475 USA Internet: gsh7w@virginia.edu UUCP: ...!uunet!virginia!gsh7w ------------------------------ Date: 9 Dec 90 23:54:51 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: UIT Status for 12/09/90 [1500 CST] (Forwarded) UIT Status Report #06 3 p.m. CST Dec. 9, 1990 Spacelab Mission Operations Control Marshall Space Flight Center The Goddard-developed Ultraviolet Imaging Telescope is currently getting long exposures on almost all its targets. Last night the instrument focused on Abell 665, a rich cluster of galaxies very close to earth. "We got very deep, all night exposures," said Susan Neff, of GSFC, an astronomer with the UIT team. "So we should be able to get 400 to 500 galaxies at once with this picture. It was probably the high point for the evening." This morning, at about 10 a.m. CST, UIT took images of the Perseus cluster of galaxies. Two previous pointings were cut short due to an orbiter hot fire test. This cluster is particularly interesting because it is not symmetrical in shape, meaning that it may be a young cluster that could give scientists information about the formation of clusters. The images taken from UIT are recorded directly ontl a very sensitive astronomical film for later development at Goddard Space Flight Center after Columbia lands. ------------------------------ Date: 11 Dec 90 04:28:25 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 - 12/05/90 MAGELLAN STATUS REPORT December 5, 1990 The Magellan spacecraft is presently performing nominally and the seven STARCALS (star calibrations) of the past 24 hours were successful with small attitude updates. Yesterday, mapping sequence M0339 and its associated parameter files was uploaded and began executing at 3:48 AM PST this morning. The radar sensor continues to operate normally. However, analysis of data from orbits #958 & 959 indicates that tape recorder tracks A1 and A3 are beginning to show the progressive deterioration that affected tracks A2 and A4. A tape management strategy using only tape recorder B is currently being evaluated. The 1.8 megabits of radar data from each full mapping pass requires four tape recorder tracks. If only one recorder is used, small gaps occur when the recorder switches from one track to another. The strategy up to this time has been to use both tape recorders, so the second unit is recording as the first reaches the end of a track and no gaps occur. It may be possible to design a strategy which uses tape recorder A only to fill the gaps. The SAR (Synthetic Aperture Radar) Data Processing Team produced five standard image swaths on Monday, December 3, three from reprocessed data records. On December 4 they produced a test image swath from orbit #951 and twelve standard image swaths from orbits #790 thru 803. The quality is normal except for a small "bright patch" at about 13 degrees south latitude. This patch is a result of a faulty SAR threshold value for one burst of SAR data. It is considered to be a minor problem, but it is being investigated and appropriate corrections will be made. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 11 Dec 90 04:42:54 GMT From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@apple.com (Ron Baalke) Subject: Magellan Update - 12/10/90 MAGELLAN STATUS REPORT December 10, 1990 The Magellan spacecraft is presently performing nominally. All STARCALS (star calibrations) over the weekend were successful with small attitude updates. On Friday, December 7, the weekly update of radar control parameter and mapping quaternion files was successfully sent to the spacecraft. Thermal and power effects of solar occultation are beginning to be seen. The spacecraft temperatures drop while in the shadow of Venus and the battery charge levels are slightly lower. Starting on Saturday, December 15, we will have periods of Earth occultation, when the playback of data to Earth is blocked by Venus. Spacecraft controllers are still analyzing the performance of on-board tape recorder A and designing a data management strategy which uses just tape recorder B. The single tape recorder approach would result in gaps of about ten seconds when the tape recorder switches from one track to another. Since the radar is mapping about 8 kilometers of the surface in each second, the potential gaps would be about 80 kilometers. But because of the actual beam width of the radar, the gaps would vary from 60 to 70 kilometers. A technical meeting with representatives of Odetics and Martin-Marietta is scheduled for December 13 at JPL to discuss the tape recorder and possible corrective actions. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 11 Dec 90 04:10:43 GMT From: julius.cs.uiuc.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@apple.com (Ron Baalke) Subject: Magellan Update - 12/04/90 MAGELLAN STATUS REPORT December 4, 1990 The Magellan spacecraft is presently performing nominally and the seven STARCALS (star calibrations) of the past 24 hours were successful with small attitude updates. Magellan is now in orbit #965, so it has completed 480 radar mapping orbits. Counting the orbits lost or degraded by this past weekend's incident, we have lost about 18 orbits which will have to be recovered during the extended mission. Later today, the weekly mapping command sequence load will be sent to the spacecraft along with a few routine commands such as tertiary heater settings, etc. While the SAR (Synthetic Aperture Radar) Processing team is awaiting the delivery of post Superior Conjunction radar tapes, effort has been directed toward processing "problem" data sets that have accumulated. A software modification was made which enabled an input data defect to be circumvented. This made possible the processing of four new image swaths from previously unprocessable data records. Two other image swaths were regenerated by the High Rate Processor to correct other problems, and were successfully processed into good quality images. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: Sun, 09 Dec 90 22:17:35 CST From: "John Schultz" Subject: Light years and such Whenever I hear about a new telescope (such as the HST, etc.) I also hear that the new telescope will be able to see even farther into the past. Now, I have no trouble with the idea of light speed, light years, etc., but how can one telescope see back farther than another? Is it due to focusing power, or somethin ssimilar? :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: : John Schultz :Disclaimer : I *pay* for this - : : University of Missouri - Columbia :do you think the bureaucracy : : Bitnet : C491153@UMCVMB.Bitnet :cares what I say??? : : Internet : C491153@UMCVMB.Missouri.EDU (128.206.1.1) : :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: : Don't dream it, be it... - Frank N. Furter, "RHPS" : :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ------------------------------ Date: 9 Dec 90 23:42:47 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Who killed Nuclear Rockets? (was Re: The Next Ten Years In Space) In article yamauchi@cs.rochester.edu (Brian Yamauchi) writes: >Given that nuclear rockets were to be such a benefit for space >exploration, what killed them? All the advanced missions were killed, and then the nuclear-rocket projects were killed because there was no mission to justify them... guaranteeing that there would be no future missions planned around them. The near-total shutdown of advanced-propulsion research in the early 1970s didn't help. >What ever happened to NERVA? What was the connection between this >project and the projects mentioned in the quotes above? NERVA was the most conservative nuclear rocket that anyone could think of, and the last to die as a result. Some of the more enthusiastic quotes may have been aimed at the more ambitious ideas. >If we had spent the money to develop the space shuttle on nuclear >propulsion instead, could we have developed a practical nuclear >orbital booster or lunar/planetary transfer vehicle? ... The latter, almost certainly, but there would then have been the problem of what to use to get to Earth orbit. The former, rather more doubtful: the orthodox nuclear-rocket systems tend to suffer from low thrust:mass ratios, making them unsuited for lower stages, and also can have a bit of a problem with fission products in the exhaust. There was some talk of a nuclear third stage for the Saturn V, which would probably have been viable had the Saturn V survived. Fission rockets tend to be inherently a little "dirty", so using them for boost from the ground would have become problematic with the cessation of above-ground nuclear testing and the reduced tolerance for radioactive garbage in the atmosphere. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ End of SPACE Digest V12 #658 *******************