Space & Astronomy

home *** CD-ROM | disk | FTP | other *** search

/ Space & Astronomy / Space and Astronomy (October 1993).iso / pc / text / spacedig / v11_3 / v11_359.txt < prev next >

Wrap

Internet Message Format | 1991-07-08 | 18KB

Return-path: <ota+space.mail-errors@andrew.cmu.edu> 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 </afs/andrew.cmu.edu/usr1/ota/Mailbox/IaEal7i00VcJI7Pk5z>; Sat, 5 May 90 02:01:44 -0400 (EDT) Message-ID: <oaEakdO00VcJA7O05F@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 5 May 90 02:01:14 -0400 (EDT) Subject: SPACE Digest V11 #359 SPACE Digest Volume 11 : Issue 359 Today's Topics: Re: Radar (was Re: Drake Equation Re: Hubble1 0Trouble mea culpa Re: Manned mission to Venus NASA Headline News for 05/04/90 (Forwarded) Re: mea culpa Voyager Update - 05/04/90 Galileo Update - 05/04/90 ---------------------------------------------------------------------- Date: 2 May 90 17:24:37 GMT From: hpcc01!hpsmdca!phil@hplabs.hp.com (Philip Walden) Subject: Re: Radar (was Re: Drake Equation Actually you are all right. Close to the array or high gain antenna (probably about a few aperture lengths) the radiation will exhibit a more linear effect with distance. Much farther away, everything looks like a point source and exhibits the inverse-square relationship. This applies to all fields, such as gravity. A flat earth of infinite radius would have a constant gravitational field with height. This is true even on our spherical earth. Within a few thousand feet of the surface, most calculations can consider the strength of gravity as a constant. ------------------------------ Date: 4 May 90 16:12:11 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Hubble1 0Trouble In article <19900503175252.7.WIDZINSKI@OPUS.SCRC.Symbolics.COM> widzinski@SAPSUCKER.SCRC.SYMBOLICS.COM (Mark C. Widzinski) writes: > There had to be some specific rule about when Discovery's responsibility > ended and HST was on its own. The cutoff point that was chosen was, in > fact, the opening of the lid. > >Does this mean that once the lid is open, it won't be closed? If >not, when will the lid be closed? The lid in fact has been closed two or three times already, when the onboard software got paranoid about some irregularity and decided to put the telescope into "safe" condition. ("Safe" condition includes having the lid closed because that eliminates worries about accidentally pointing the telescope at the Sun.) The significance of the first opening was the possibility that the lid might stick, which would make the telescope useless. Conceivably it could stick on a later opening, with the same effect, but having opened once it is likely to be able to open again. -- If OSI is the answer, what is | Henry Spencer at U of Toronto Zoology the question?? -Rolf Nordhagen| uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 4 May 90 14:27:58 GMT From: cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!IDA.ORG!pbs!pstinson@tut.cis.ohio-state.edu Subject: mea culpa mea culpa, mea culpa, mea maxima culpa. I totally misread the Apollo 204 news item. It dawned on me at 3 in the morning and I've already gotten a couple of e-mails reminding me 204 IS Apollo 1. To prevent a million other e-mails on this subject, I admit I commited a major gaff here. (It would have helped if the original posting was not so clinically cold. It's like giving an update on the status of BB-39 and expecting every reader to immediately realize that's the U.S.S. Arizona.) Will 204 once it is entombed in that missile silo have an ARIZONA type memorial? It deserves one. ------------------------------ Date: 4 May 90 23:07:02 GMT From: zephyr.ens.tek.com!tektronix!percy!gary@uunet.uu.net (Gary Wells) Subject: Re: Manned mission to Venus In article <3332@calvin.cs.mcgill.ca> msdos@calvin.cs.mcgill.ca (Mark SOKOLOWSKI) writes: >I would like to start a new discussion about a manned mission to Venus. bunch of stuff excised >will be the first to volunteer to go there... After all our technology >can enable us to make life bearable even at 900 F and 90 athmospheres > >Mark S. Seems like a good idea to me. If you're going to have to live under a bubble anyway, who _really_ cares what the outside is like? Having oxygen available would be a real plus. Seems like most of the real hard problems about moon or mars habitation revolve around supply of oxygen. On a side note, 9 months isn't all that bad. Our forebears often survived _years_ long trips on the sailing ships. Often in cramped,dark,wet quarters. On poor rations. Under sadistic officers. I think we could stand 9 months in a space ship. Even the Apollo's. -- -------------------------------------------------------------------------------- Still working on _natural_ intelligence. gary@percy (...!tektronix!percy!gary) ------------------------------ Date: 4 May 90 19:22:46 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 05/04/90 (Forwarded) ----------------------------------------------------------------- Friday, May 4, 1990 Audio Service: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Friday, May 4... Space flight medical authorities at the Johnson Space Center have cleared Sam Durrance for flight. His medical condition has been evaluated and resolved determining he is qualified to serve as Astro-1 payload specialist in the upcoming launch of the Columbia targeted for May 17. Meanwhile, ground crews at Kennedy Space Center continue preparations for launch of the space shuttle Columbia. The routine launch readiness review conducted yesterday revealed no outstanding technical issues. Post-test inspections are now underway following the hot firing of auxiliary power unit #3. ******** Dryden Flight Research Facility engineers continue turn around work to prepare the orbiter Discovery for departure tomorrow. Current activities include removal of an OMS/RCS thruster from the aft end for vendor analysis. Following completion of the power checks and offload operations, the orbiter will be bolted atop the modified 747 Shuttle Carrier Aircraft. ******** The Hubble Space Telescope analysts continue to examine the contents from the three onboard tape recorders. Also, to evaluate a fine guidance sensor pattern that compares pinpoints of starlight with predicted data. Routine operations include the process of putting in the first space science specifications. ******** The Galileo spacecraft is traveling around the sun at almost 69,000 miles per hour logging almost 391 million miles since launch. Now 94 million miles from Earth and over 89 million miles from the sun, science activities continue to include measurements of the interplanetary environment. The stored information is sent back to Earth about twice a week. ******** Aerospace Daily reports Senator Albert Gore suggested the Bush Administration attempt to come up with ways to pay an estimated cost of $500 million for moon and Mars missions. The Daily says Gore praised the administration increase in the NASA budget, but sees it falling short by about $1 billion for FY91. ******** ---------------------------------------------------------------- Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. Tuesday, May 8...... 11:00 A.M. ROSAT news briefing and satellite showing at KSC. Launch date is May 31. Wednesday, May 9.... 12:00 Noon STS-31 crew post flight news confernce at Johnson Space Center. 1:49 P.M. DARPA launch of Scout/MACSAT's. Thursday, May 10.... 11:31 A.M. NASA Update will be transmitted. Friday, May 11...... 11:00 A.M. Dr. Clifford Stoll, author of "The Cuckoo's Egg" will lecture on computer security. NASA Select TV: Satcom F2R, Transponder 13, 72 Degrees West Longitude, Audio 6.8, Frequency 3960 MHz. All events and times are subject to change without notice. Please note, due to coverage of the STS-31 flight scheduled for May 17, NASA Update will transmit the next week, May 24. ----------------------------------------------------------------- These reports are filed daily, Monday through Friday, at 12:00 Noon, EDT. This is a service of the Internal Communications Branch, NASA Headquarters. ------------------------------ Date: 4 May 90 19:41:41 GMT From: mojo!SYSMGR%KING.ENG.UMD.EDU@mimsy.umd.edu (Doug Mohney) Subject: Re: mea culpa In article <8147.2641592e@pbs.uucp>, pstinson@pbs.uucp writes: >major gaff here. (It would have helped if the original posting was not so >clinically cold. It's like giving an update on the status of BB-39 and >expecting every reader to immediately realize that's the U.S.S. Arizona.) Will >204 once it is entombed in that missile silo have an ARIZONA type memorial? It >deserves one. They also placed (dumped?) the remains of the "Challenger" in a missile silo down on the Cape. How many silos do they have? I think an earth-bound memorial site wouldn't be a bad idea.... Doug ------------------------------ Date: 4 May 90 15:11:38 GMT From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Voyager Update - 05/04/90 Voyager Mission Status Report May 4, 1990 Voyager 1 Voyager 1 continues to collect routine cruise science data. One frame of high-rate Plasma Wave (PWS) data was recorded on April 24. High-rate Ultraviolet Spectrometer (UVS) observations of HD 120324 and HD 217675 were conducted on April 20 and April 23, respectively. All of the latter observation was lost due to lack of Deep Space Network (DSN) coverage. A Computer Command Subsystem (CCS) timing offset determination performed on April 25 indicated that an unexpected offset of approximately 120 milliseconds existed between the Flight Data Subsystem (FDS) and both CCS processors. This situation is under investigation. Also on April 23 the Attitude and Articulation Control Subsystem (AACS) B and C gyros were turned on in preparation for the ASCAL executed on April 27 and the spacecraft roll manuever (MAGROL) sequenced for May 1. No problems were experienced and spacecraft performance was nominal. On April 24 it was discovered that no spacecraft engineering telemetry had been processed during the entire preceding pass of the 70 meter antenna at Goldstone (DSS-15). This anomaly was not noticed by "off-shift" monitoring personnel and no project personnel were notified. Following analysis, the Test and Telemetry Subsystem (TTS) was found to be configured to process wide band instead of high speed data. This configuration change should have been made prior to the DSS 15 pass. Voyager 2 Voyager 2 also continues to collect routine cruise science data. One frame of high-rate PWS data was recorded on April 24. High-rate UVS observations of iota Herculis and HD 193322 were conducted on April 20 and April 25, respectively. The 2 hours and 50 minutes of the UVS high-rate data taken on HR6558 was badly degraded due to rain and is probably unusable. The data taken on HD193322 on April 25 was of good quality. On April 25 AACS, CCS, and FDS memory read-outs were performed. Spacecraft and DSN performance appeared nominal for the activity. However, excessive lines were missed by TTS LP17 during the AACS read-out. The CCS and FDS readouts were very clean with very few outages. Also on April 25, a sequence to calibrate the Plasma Subsystem (PLS) and Magnetometer Subsystem (MAG) was executed. The calibrations went nominally and the instrument data looked good. However, a problem was observed in which two science channels were not being processed and output to the General Science character printer. Subsequent analysis revealed that the problem was present when TTS software version 9.0 was on line and not present with version 8.8. 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 | Go Lakers! ------------------------------ Date: 4 May 90 22:31:55 GMT From: usc!jarthur!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Galileo Update - 05/04/90 GALILEO MISSION STATUS REPORT May 4, 1990 As of noon Friday (PDT), May 4, 1990, the Galileo spacecraft is 94,347,620 miles from the Earth, 22,390,620 miles from Venus and traveling at a heliocentric velocity of 68,620 miles per hour. The spacecraft is in cruise mode-dual spin and is spinning at 3.15 rpm as measured by its star scanner. Downlink telemetry rate through the Low Gain Antenna (LGA-1) is 40 bps and the spacecraft attitude sun point angle is at 1.4 degrees. Round trip light time is 16 minutes, 50 seconds. Two SITURNS to lead the sun were successfully performed on April 30 and May 4. The spacecraft performance for these activities was as expected and without incident. With the beginning of the Australia 70 meter antenna (DSS-43) tracking pass on April 30 telemetry data indicated that a despun Command Data Subsystem (CDS) Critical Controller (CRC) A Power on Reset (POR) had occurred sometime between the end of track late on April 28 and the start of track on April 30. Other spacecraft telemetry data was reviewed and spacecraft performance was as expected except for the POR indication. Later on April 30 with the POR telemetry indication still present, the spacecraft successfully performed a SITURN and other activities without incident. No similar indications were evident elsewhere in the CDS. In fact, all other CDS telemetry indicators were as expected. The POR signal is generated by the CDS power converter and sent to the corresponding Hardware Command Decoder (HCD), and or spun and despun Critical Controller Circuitry (CRC). The POR signal is normally generated when either power converter detects a low voltage condition for several tens of microseconds. No interruptions in processing or loss of functionality were observed. Once a despun CRC POR indication is received the logic circuity in the CDS holds that state (via a latch device) until it is reset by ground command. Upon completion of initial anomaly analysis, several real-time command troubleshooting actions were taken to reset the POR bit and verify operation of the CRC logic circuitry. The actions successfully reset the POR bit and verified that the POR related logic circuitry is functioning properly. The success of these actions provides confidence that the critical controller circuity and telemetry circuits which monitor this function are working properly. Subsequent to the ground actions, a command was sent late on April 30 to reset the Command Loss Timer again in both halves of the CDS because the CDS POR troubleshooting actions were executed from one side of the CDS. The cause of this anomaly is unknown. Subsequent test/analysis are in process investigating the possibility of circuit sneak paths, noise/part failure sensitivities and possible interaction with AC/DC imbalance anomaly. Cruise Science Memory Readouts (MROs) were successfully performed for the Magnetometer (MAG), Extreme Ultraviolet (EUV) and Dust Detector (DDS) instruments on May 1 and May 4. The Energetic Particles Dectector (EPD) instrument was powered on and commanded from Sector 4 to Sector 0 on May 1 in preparation for the upcoming Trajectory Course Maneuver (TCM-4B). Contamination analysis has predicted that Sector 0 is the minimum contamination position for the EPD. As part of the general EPD activity, an EPD MRO was performed. After the MRO, the EPD was turned off. The AC and DC bus imbalance measurement fluctuated slightly varying about 0.7 volt on the DC measurement and about 3.5 volts on the AC measurement. The AC imbalance measurement fluctuated during a period of no spacecraft load switching or motion activity. The design of TCM-4B was reviewed and approved by the Project on May 4. This maneuver will consist of two portions totalling approximately 11.3 meter/second change in velocity and will occur on May 11 and 12. Deep Space Network (DSN) and Project representatives are continuing to investigate the Command System anomaly which resulted in transmission of a Command File for the Galileo VE-3 sequence two minutes earlier than requested by the Mission Control Team. A procedural work around to the problem has been identified and is now being used. The DSN is considering a fix to the DSN Command Processor Assembly (CPA), but no decision has been as to whether it is more appropriate to fix the problem or continue to use the procedural work around. 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 | Go Lakers! ------------------------------ End of SPACE Digest V11 #359 *******************