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 ; Tue, 10 Apr 90 01:30:47 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 10 Apr 90 01:30:19 -0400 (EDT) Subject: SPACE Digest V11 #239 SPACE Digest Volume 11 : Issue 239 Today's Topics: Pegasus launch is a success! Re: HST Image Status for 04/01/90 (Forwarded) Galileo Update - 04/09/90 Re: Skylab Payload Status for 04/05/90 (Forwarded) Payload Status for 04/09/90 (Forwarded) Re: O-rings and launching in cold weather Re: Recommendations on Telescope Purchase. Re: Skylab ---------------------------------------------------------------------- Date: 5 Apr 90 19:58:51 GMT From: skipper!shafer@ames.arc.nasa.gov (Mary Shafer (OFV)) Subject: Pegasus launch is a success! The subject line says it all. It dropped off the hooks at about 1208 PDT and ignited 5 _loooong_ seconds later. Performance was nominal. Excitement was rampant. -- Mary Shafer shafer@skipper.dfrf.nasa.gov or ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA ------------------------------ Date: 9 Apr 90 01:51:08 GMT From: bfmny0!tneff@uunet.uu.net (Tom Neff) Subject: Re: HST Image Status for 04/01/90 (Forwarded) It seems to me there may already be someone at JPL or Goddard reading this now who could pull the necessary levers to get some images transferred to an anonymous FTP directory every so often. If so, how about speaking up. ------------------------------ Date: 9 Apr 90 18:09:15 GMT From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Galileo Update - 04/09/90 GALILEO MISSION STATUS REPORT April 9, 1990 The Galileo spacecraft is now 80,768,210 miles from the Earth, 13,725,620 miles from Venus and traveling at a heliocentric velocity of 79,790 miles per hour. Round trip light time is 14 minutes, 22 seconds. Two SITURNS to lead the sun were successfully performed on April 2 and 5. Spacecraft performance for these activities was as expected and without incident. Continued periodic characterization tests were successfully performed for selected telecommunications hardware elements. Command Detector Unit and radio frequency subsystem element tests were completed on April 1 and April 2, respectively to characterize receiver automatic gain control operation, receiver tracking loop operation and command detector signal-to-noise ratio performance. The tenth RPM thruster "flushing" activity was successfully performed on April 6. The activity flushed the Z, L and S thrusters only. The P thrusters were not flushed since they are used periodically to perform the SITURNS. These activities were performed at 40 bps and consequently thruster temperature profiles were not available due to the low telemetry sample rate. Successful flushing was inferred from other spacecraft measurements/events, including attitude control performance and thruster counts. The Energetic Particles Detector (EPD) instrument was powered on and commanded from Sector 4 to Sector 0 on April 6 in preparation for the upcoming Trajectory Course Maneuver (TCM-4A). Contamination analysis has predicted that Sector 0 is the minimum contamination position for the EPD. As part of this general EPD activity, an EPD Memory Read Out (MRO) was also performed. After the MRO, the EPD was turned off. Memory readouts were successfully performed as planned on April 2, 5 and 6 to return cruise science data from the Extreme Ultraviolet (EUV), Magnetometer (MAG) and Dust Detector (DDS) instruments. Three attitude control related tests were performed on April 2 and 3. Tests consisted of collecting data to update calibration information for accelerometers, gyros and spin bearing assembly drag torque. The DC bus voltage imbalance measurement was observed to have dropped significantly during the Deep Space Network (DSN) non-tracking period from end of track on March 30 to the beginning of track in the afternoon on April 1. The observed drop was about 5 volts and tended to a more-balanced bus condition. The imbalance reading changed from 21.6 volts to about 16.5 volts. Subsequent to the DC imbalance measurement drop, it has fluctuated between about 16.5 and 17.5 volts. No spacecraft activities or power switching events were executed from the stored sequence during the non-tracking periods; all other spacecraft telemetry measurements were as expected. The AC bus voltage imbalance measurement has remained relatively stable varying between 47.5 and 48.2 volts. Commands were sent on April 6 to modify the maneuver telemetry map to include additional Retropropulsion Module (RPM) temperature and Attitude and Articulation Control Subsystem (AACS) telemetry measurements to provide improve system temperature and delta velocity performance visibility during the TCM-4A maneuver. The TCM-4A sequence generation and command products were reviewed and approved by the Project on April 5. The first of the four maneuver portions was transmitted on April 8. The other three portions will be transmitted on subsequent days April 9, 11 and 12. TCM-4A will be executed from April 9 thru 12 and consist of four vector mode portions. Each portion (a day's worth of maneuver activity) will impart a delta velocity magnitude of about 6.18 meters/sec. The maneuver will be performed using only the L-thrusters with benign duty cycles. A total of 6372 pulses will be used with a total estimated fuel consumption of 23.2 kg. The DSN has completed elevation bearing inspections at the 70 meter antenna at Goldstone, California (DSS-14), and inspection is in process at the 70 meter antenna at Madrid, Spain (DSS-63). No problems have been reported that would require additional antenna downtime. There will be no impact to TCM-4 tracking support if no additional problems are discovered. The DSN reports that Mission Readiness Test (MRT) on the 34 meter antenna at Canberra, Australia (DSS-45), has qualified that station for support of Galileo when X-band capability becomes available. The results of the S-band Delta DOR demonstrations on Galileo, carried out in January and February, show that five of the seven events yielded very good Very Large Baseline Interferometry (VLBI) data. The other two events were lost due to a ground software change-of-day problem and the previously reported spacecraft fault protection execution (entry into spacecraft safing on January 15, 1990). Lessons learned from this exercise will be incorporated into Earth Gravity Assist (EGA) Navigation planning. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 | ------------------------------ Date: 9 Apr 90 20:27:42 GMT From: shlump.nac.dec.com!skylab.enet.dec.com!fisher@decuac.dec.com Subject: Re: Skylab The gadget that they were planning to save Skylab with was called the TRS, Teleoperator Retrieval System. It was cancelled when it became clear that Skylab was coming down before the shuttle went up. TRS would have been useful for other things, possibly, as well, but Skylab was its only real customer at the time. Jeez but Skylab (and its controllers!) was neat...they reactivated it after n years of inactivity, got the batteries charged and the gyros running and gained some reasonable degree of attitude control before it died. It reported calmly on the way down as the various pieces of itself burned and died. Its last message reported that the solar wings had detatched. Sigh. Burns Fisher (Note my node name in the usenet path!) VMS DECwindows and Display PostScript fisher@decwin.enet.dec.com ------------------------------ Date: 9 Apr 90 21:59:29 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Payload Status for 04/05/90 (Forwarded) ------------------------------ Date: Mon, 9 Apr 90 12:21:39 PDT From: ames!nasamail.nasa.gov!payload.projects Daily Status/KSC Payload Management and Operations 04-05-90. - STS-31R HST (at pad-B) - The HST confidence test was completed and battery charging was terminated on third shift today. Battery charging will continue today following the completion of pad clear hazardous operations. - STS-35 ASTRO-1 (at OPF) - ASTRO closeout activities and experiment servicing were worked Wednesday and will continue today. - STS-40 SLS-1 (at 0&C) - Rack and floor installation into the module was started Wednesday and will continue today. - STS-42 IML-1 (at O&C) - Staging activities on the floor and racks 5 and 8 were worked on Wednesday. Floor staging along with racks 3, 4, 7, 8, and 9 staging operations are scheduled for today. - STS-45 (Atlas-1)- Flight trunnion installation was completed on Wednesday. Joint kit installation on frame 4 was also worked on Wednesday and will continue today. - STS-55 SL-D2 (at O&C) - Rack 12 staging activities will continue today. - HST M&R (at O&C) - Cable continuity and isolation will continue today. ------------------------------ Date: 9 Apr 90 22:21:16 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Payload Status for 04/09/90 (Forwarded) Daily Status/KSC Payload Management and Operations 04-09-90. - STS-31R HST (at pad-B) - HST closeouts were completed and the payload bay doors were closed for flight at 0630 hours Sunday. Launch countdown support continues with the PCG to orbiter ivt occurring first shift today. - STS-35 ASTRO-1 (at OPF) - ASTRO closeout activities and experiment servicing are continuing today. - STS-40 SLS-1 (at 0&C) - Rack and floor installation into the module was active Friday and Saturday and will continue today. - STS-42 IML-1 (at O&C) - The experiment floor was transferred to level IV on Saturday. Today module pyrell foam replacement along with racks 3, 8, 9, and 11 staging operations are scheduled to be worked. - STS-45 (Atlas-1)- Pallet to pallet mating was started Friday and will continue through second shift today. - STS-55 SL-D2 (at O&C) - Rack 12 staging activities will continue today. - HST M&R (at O&C) - ORUC cable installations will continue today. ------------------------------ Subject: Re: O-rings and launching in cold weather Date: Mon, 9 Apr 90 9:42:01 MESZ From: Joseph C. Pistritto Mailer: Elm [revision: 64.9] I'm looking at the little table here "Figure 10" in Feynman's book which has a chart of the temperature and the O-ring damage level reported. Now while the 3 lowest temperature points show damage, so do 3 higher temperature points. Probably more significantly, the flight with the most damage (51C) was at the lowest temperature. The thing that most impresses me about this table though, is that, quite independently of the temperature, the joint obviously wasn't working right. How this basic defect could go uncorrected for so long was STUNNING. It's really obvious that you don't put a material like rubber in a place where you expect FLAMES to be burning it away. So quite obviously there was a more fundamental problem that was just glossed over for a long time, and that was the critical failure, at least as much as the decision to launch at a low temperature. At that time of the year, they could have waited a few days for higher temperature, but they still would have had this problem of the rings burning, which very well would have come down and nailed them on a future flight, if not this one. -- Joseph C. Pistritto (jcp@brl.mil -or- cgch!bpistr@mcsun.eu.net) Ciba Geigy AG, R1241.1.01, Postfach CH4002, Basel, Switzerland Tel: +41 61 697 6155 (work) +41 61 692 1728 (home) GMT+2hrs! ------------------------------ Date: 9 Apr 90 15:53:09 GMT From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!uwm.edu!zaphod.mps.ohio-state.edu!mips!bridge2!jarthur!jokim@ucbvax.Berkeley.EDU (John H. Kim) Subject: Re: Recommendations on Telescope Purchase. Mail didn't work. In article <250@usna.NAVY.MIL> nardi@cad.usna.mil.UUCP (Peter A. Nardi (CompSci) ) writes: > > I'm interested in purchasing an 8" SCT telescope. The >two models I'm considering are from Meade (the 2080) and Celestron >(the classic - 8). Has anyone had any experience with these scopes, >good or bad? There's not much difference in price, so recommendations >on quality of optics, drives, etc would be helpful. Both _Sky and Telescope_ and _Astronoy_ do field tests of both brands (and others) each year. Check the library. One thing that has come up in sci.astro is to be prepared to test the optics. Many people have had to return a couple of scopes to get one with better optics. Both companies are very reasonable with their return policies and will replace an "unacceptable" scope without question (generally). If you don't know how to test your optics, learn, or better yet, find someone who does. A good deal of equipment is often necessary to get a scope with optics as good as the ads say (1/20 wave, diffraction limited, etc), but I hear even the most basic tests will weed out the worst scopes. Post to sci.astro for suggestions on testing-- I don't know, I don't own a scope, I've just wanted one for the last ten years. -- John H. Kim jokim@jarthur.Claremont.EDU ------------------------------ Date: 9 Apr 90 15:59:42 GMT From: snorkelwacker!usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@bloom-beacon.mit.edu (Henry Spencer) Subject: Re: Skylab In article J_DELANO@UNHH.BITNET writes: > was there ever any real chance of saving Skylab? I read once taht >if the space shuttle had been a bit more advanced a little sooner, then >they would have gone up to repair Skylab. Wouldn't it have been worth it? There was some chance of a Skylab rescue, and in fact for a while it was planned to be on the second shuttle flight. Unfortunately, Skylab came down earlier than expected and the shuttle flew later than expected. As to whether it would have been worth it... somewhat of an open question. The thing wasn't really designed for re-use; in particular, there were no major provisions for resupply or repair in space, and it would have needed both to be an operational station again. > And, on a related note, are the Soviets simply going to de-orbit >Salyut 7 like they do all the progress modules? Probably. It will actually be a bit trickier than that, because they no longer have good control over it; they'll have to send something up to get it. On the other hand, they've done that sort of thing before. -- Apollo @ 8yrs: one small step.| Henry Spencer at U of Toronto Zoology Space station @ 8yrs: .| uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ End of SPACE Digest V11 #239 *******************