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, 27 Mar 91 02:03:40 -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, 27 Mar 91 02:03:34 -0500 (EST) Subject: SPACE Digest V13 #304 SPACE Digest Volume 13 : Issue 304 Today's Topics: * SpaceNews 25-Mar-91 * Re: "Follies" Re: Japan Moon Probes article Re: Galileo asteroid imaging Where can I find space GIFs? Galileo Update - 03/20/91 Magellan Update #2 - 03/20/91 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: 23 Mar 91 02:03:31 GMT From: ka2qhd!kd2bd@rutgers.edu (John Magliacane) Subject: * SpaceNews 25-Mar-91 * SB SPACE @ AMSAT < KD2BD $SPC0325 * SpaceNews 25-Mar-91 * Bulletin ID: $SPC0325 ========= SpaceNews ========= MONDAY MARCH 25, 1991 SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It is published every week and is made available for unlimited distribution. * U2MIR NEWS * ============== U2MIR Activity Patterns by John Shalamskas, KJ9U 3/17/91 Evidently, the best times to work the cosmonauts "live" are weekends UTC, with some leeway for Fridays and Mondays. Currently, their work schedule of 08:00 to 23:00 Moscow time means that they are asleep from 23:00 to 08:00 Moscow time. Watch for passes during their wakeful hours if you wish to have a "live" conversation. It's quite an experience! UTC: "Prime Time" hours are from 05:00 to 20:00 Friday - Monday For the record, his name is pronounced "Moo'sah", and he really does have some trouble with the English language. * STS-37 NEWS * =============== A Flight Readiness Review for STS-37 is scheduled for March 26 and 27. Shuttle Amateur Radio EXperiment (SAREX) schedules have already been made with various schools around the country. On 05-Apr-91, several "bridges" have been scheduled so astronauts can communicate directly with school children using Amateur Radio. Contacts will be made at 15:11, 18:29 and 20:20 UTC using both voice and slow-scan television (SSTV) on this date. Audio re-transmissions of these bridges should be available on WA3NAN, the Amateur Radio club station at the Goddard Space Flight Center in Greenbelt, Maryland. [Info via N9JEL] * PACSAT NEWS * =============== After spending two weeks studying memory dumps, NK6K and G0/K8KA have determined the cause of the on-board computer crash which occurred on AO-16 March 2. NK6K traced the crash back to an inefficient way in which a "homebrew" PACSAT user program requested information about new files stored on the BBS. Because of the slow way the search for new files was being performed and the fact that at the time of the crash there were over 560 files stored, the file server took a lot longer to search than normal. After sixty seconds, a critical software timer timed out, and as NK6K put it, "the dominoes started falling." Now that this problem has been identified, G0/K8KA has made a change in the PACSAT file server software so that this problem won't re-occur. Also, new implementation notes will be published so that all writers of PACSAT ground station user software will be aware of the change in the PACSAT Protocol. As of 03:00 on March 15, 1991, the BBS on AO-16 was back in operation. Likewise, the BBS on LUSAT-OSCAR-19 (LO-19) was on-line, according to LU7XAC. It is believed that the LO-19 on-board computer crash was due to the same problem, manifest in a slightly different way. NK6K points out that PACSAT BBS software is much more robust with each new version, and the time between crashes is increasing. [Info via ANS] * INTERSTELLAR QRM * ==================== 145.825 MHz has become a popular frequency for VHF radio links with OSCAR satellites. At the present time, 145.825 MHz is used as a downlink for both OSCAR-11 (UoSAT-2) and OSCAR-17 (DOVE-1). RS-14/OSCAR-21 is a close neighbor, using 145.822 MHz for a CW telemetry beacon. At the same time, RS10 and RS11 use this frequency (+/- 5 KHz) for uplinks to their auto- transponders, or "robots". The popularity of 145.825 MHz has created some real problems! On frequent occasions, OSCARs 11, 17 and 21 can all be heard at once, causing severe interference between satellites and making it impossible to copy ANY satellite when all three come into range at once. There have also been occasions when RS10 or RS11's "robot" uplinks have been interfered with by constant carrier (FM) emissions from OSCAR 11 and/or 17. Since many OSCAR satellites are placed in sun-synchronous orbits, they often come into range of a given satellite groundstation at about the same time every day, and if they all use the same beacon frequency, the severe interference problem results. 145.825 MHz is simply getting too crowded for practical use. Even the short-lived BADR-1 spacecraft used this frequency as an outlet for its telemetry beacon. Perhaps we should look toward using the 144.300 to 144.500 MHz OSCAR subband in future amateur spacecraft. Something to think about.... de KD2BD * TNX QSL! * ============ A special thanks to all those who sent QSLs to SpaceNews: KB2HMK : Michel Zadoroznyj, Garfield, New Jersey, USA N3IKS : John Ford Gibson III, Philadelphia, Pennsylvania, USA N6YGD : Donald Bowtell, Byron, California, USA WB9OKM : Leland Ronzheimer, Waukegan, Illinois, USA WT0N : B.J. Arts, Plymouth, Minnesota, USA ...and e-mail messages: KB2FID, N2AAM, VK2BBD, WA2N, TI3DJT, KC4UZA, SM6JNS, N9JEL * FEEDBACK WELCOMED * ===================== Feedback regarding SpaceNews reports may be directed to the editor using any one of the following paths: INTERNET : kd2bd@ka2qhd.de.com PACKET : KD2BD @ NN2Z.NJ.USA.NA UUCP : ...rutgers!ka2qhd!kd2bd MAIL : John A. Magliacane, KD2BD Electronics Technology Department Advanced Technology Center Brookdale Community College 765 Newman Springs Road Lincroft, New Jersey 07738 U.S.A. /EX -- John A. Magliacane FAX : (908) 747-7107 Electronics Technology Department AMPR : KD2BD @ NN2Z.NJ.USA.NA Brookdale Community College UUCP : ...!rutgers!ka2qhd!kd2bd Lincroft, NJ 07738 USA VOICE: (908) 842-1900 ext 607 ------------------------------ Date: Thu, 21 Mar 91 19:43:17 EST From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Re: "Follies" >From: dil@mace.cc.purdue.edu (Perry G Ramsey) >Subject: Re: "Follies" >Summary: Apples to Granite comparison >> A comparison with past efforts is interesting. According to (I think) G. >> Harry Stein, both the Plymouth Rock and Salt Lake City colonies where started >> with 50 middle to upper middle class famlies selling everything they owned >> to pay for the voyage. >The obvious differences are that both Massachusetts and northern Utah >support human life quite readily. Food, water, building materials, >etc. are all readily and cheaply available. In sharp contrast to the >moon. Though as far as the Plymouth colonists were concerned, they might as well have been on the surface of the moon. And if a group with the intellect and preparedness of the Plymouth colonists ever land on the moon, I expect they'll all rush out without pressure suits and be dead in a few minutes. Before we really get going on this latest round of historical analogies (much like the one last year and the one the year before that), might I point out that trying to make historical comparisons between two situations in which the individual parameters are almost all different is very unlikely to produce any useful conclusions? :-) >Of course, the Salt Lake City and Plymouth colonists sold everything >and endured great hardship to GET AWAY from the government, not to >go live in a government owned hole in the ground. While there may have been some pressure on Puritans in England, I believe the main reason they wanted to move to America is that it enabled them to set up their own tyrannical (theocratic) local government. It wasn't so much liberty for Puritans they needed as it was the ability to persecute non-Puritans. I suspect the first space colonists will be united more by their interest in space than by political agendas. >Perry G. Ramsey Department of Earth and Atmospheric Sciences >dil@mace.cc.purdue.edu Purdue University, W. Lafayette, IN USA >perryr@vm.cc.purdue.edu *** IMAGINE YOUR LOGO HERE ****** John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 22 Mar 91 15:04:40 GMT From: phoenix!elturner@princeton.edu (Edwin L Turner) Subject: Re: Japan Moon Probes article In article <1991Mar22.072949.18057@jato.jpl.nasa.gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes: >The Times says the $100 million mission would make the >Japanese the third group to land a probe on the moon, after the >U.S. and the Soviet Union. The story says the probes will be >ready in Spring, 1996. And you can safely bet that they will be, too. Ed Turner "The truth is never taken phoenix!elturner From another. One carries it always By oneself." or elturner@phoenix.Princeton.EDU - Tetto Giko, 1369 ------------------------------ Date: 23 Mar 91 02:29:16 GMT From: usc!samsung!munnari.oz.au!uhccux!tholen@ucsd.edu (David Tholen) Subject: Re: Galileo asteroid imaging >> The lightcurve variations suggest a complex shape, and the images >> may be quite dramatic. > > Complex? I'd prefer the term "asymmetric". More egg-shaped than the usual > tri-axial ellipsoids used for modeling lightcurves. I'm confident that the > images we do get will be dramatic, but I'm biased. We will probably also > get a lot of blank frames, because the asteroid's location won't be known > that well, but we're working on it. Just to briefly followup on my earlier response, the 1988 lightcurve published by DiMartino could be considered complex. However, they did not mention in their paper that the lightcurve was obtained within a few degrees of the galactic center. I am confident that some of the fine-scale "complex" structure seen in their lightcurve is, in fact, due to field star contamination. More recent lightcurves are substanitally smoother in appearance, though asymmetric. ------------------------------ Date: 20 Mar 91 18:26:04 GMT From: mixcom!jjwwjj@uunet.uu.net (Robotic Systems) Subject: Where can I find space GIFs? Can someone please tell me where I might find GIFs of planets (ie. NASA pictures) and who might send them to me via e-mail? I do not have ftp. Thanks. Clint Laskowski Robotic Systems robots@mixcom.com ------------------------------ Date: 20 Mar 91 21:36:53 GMT From: swrinde!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Galileo Update - 03/20/91 GALILEO STATUS REPORT March 20, 1991 Today, the Galileo spacecraft is about 36 million miles from Earth and 110 million miles from the Sun, traveling at a heliocentric speed of 68,700 miles per hour. Round-trip communication time is 6 minutes, 24 seconds. Galileo is executing a Trajectory Correction Maneuver to help shape the flight path for its encounter of the asteroid Gaspra on October 29. In the maneuver Galileo will fire its small thrusters on and off during a period beginning at about 10 AM Pacific Standard Time (PST) and concluding at about 1:30 PM PST. The firings will result in a velocity change of about 5 miles per hour. For the rest of the week, the spacecraft will continue with routine housekeeping activities and readouts of data from science instruments. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant. /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | |_____|/ |_|/ |_____|/ | ------------------------------ Date: 20 Mar 91 21:40:48 GMT From: swrinde!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Magellan Update #2 - 03/20/91 MAGELLAN STATUS REPORT DMS-A Tape Recorder Review March 20, 1991 JPL, Martin Marietta, and Odetics conducted a review of the progress in analyzing the DMS-A (Data Management Subsystem-A) tape recorder problem on Monday, March 11 at JPL. Assessment of the data played back from Test #3 on the spacecraft DMS-A tape recorder has shown a number of areas which are confusing. Test #3 involved recording known test data patterns on each of the four tape recorder tracks at both the high and low record rates in order to investigate the "pattern sensitivity" of the problem. The tape recorder motor current seen in the real-time spacecraft telemetry appeared normal, rather than showing the noise spikes associated with the DMS-A problem. This noise is caused by the motor control circuitry trying to track a noisy clock signal recovered from the data on tape. Despite the apparently "good" motor current, the replayed data itself appeared to be seriously degraded. Most strikingly, no data at all appeared to be recovered from track 2, the first of the DMS-A tracks to begin to go bad. This calls into question the earlier Test #1 result, which had used the failure to find data on an "erased" area of Track 2 to confirm that the erase mechanism is working satisfactorily. A second replay of the same recorded test data (from only Track 1) was performed on Friday, March 8, to attempt to resolve this confusion. Early assessments of the second playback show substantial differences from the first playback. In fact, the data appeared to be quite good at first glance. Martin and JPL are in the process of re-examining both data playbacks to resolve these assessments. The ground tests at Odetics have shown that several of the candidate failure mechanisms did not cause the same pattern of data replay problems which have been characteristic of DMS-A. In fact, the ground tests have shown the units tested to be highly robust against the faults induced, including failure of the fine erase head winding, partial failure of the coarse erase head winding, and partial magnetization of the record head. The most promising candidate failure mechanism to emerge from the ground tests is a possible "stuttering" of the clock provided to the tape recorder from the Command Data Subsystem (CDS) computer. By inserting "extra" clock pulses, such a clock problem could cause the data encoding/decoding mechanism to fail in a pattern similar to many of the observed data errors. Such a clock problem could be caused by ringing or noise affecting the clock transfer over a short length of cable from the CDS to DMS-A. The transfer cable lengths to DMS-A and DMS-B are equal, and no such problem has been seen on DMS-B. The immediate actions after the review were to concentrate on reaching a sound assessment of the real results from Test #3, so as to separate true spacecraft problems from ground data handling anomalies. In addition, the planning for the delayed Test #2 on the spacecraft, using an area of tape which has not been used since cruise (well before the DMS-A fault appeared) is continuing. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant. /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | |_____|/ |_|/ |_____|/ | ------------------------------ End of SPACE Digest V13 #304 *******************