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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/MZiJa=:00VcJ8E5E4W>; Sun, 21 Jan 90 01:41:16 -0500 (EST) Message-ID: <QZiJZk200VcJ8E3U4Z@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sun, 21 Jan 90 01:40:48 -0500 (EST) Subject: SPACE Digest V10 #450 SPACE Digest Volume 10 : Issue 450 Today's Topics: Galileo Update - 01/19/90 radiation hazard from retrieving gallieo Space Station Freedom to run UNIX NASA Headline News for 01/19/90 (Forwarded) Blackbird vs. Foxbat Re: Space Station Freedom to run UNIX ---------------------------------------------------------------------- Date: 20 Jan 90 02:28:50 GMT From: cs.utexas.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@tut.cis.ohio-state.edu (Ron Baalke) Subject: Galileo Update - 01/19/90 GALILEO MISSION STATUS REPORT JANUARY 19, 1990 As of Friday, January 19, 1990, the Galileo Spacecraft is 18,758,910 miles from the Earth, 7,862,150 miles from Venus and was travelling at a Heliocentric velocity of 76,300 miles per hour. Round trip light time is 3 minutes, 36 seconds. A SITURN to the Sun was successfully performed without incident on January 14. Spacecraft performance was nominal, as expected. A total of 1221 real-time commands have been transmitted to Galileo. Of these, 846 have been pre-planned in the sequence design and 375 were not. In the past week a total of 70 real-time commands were transmitted; one was pre-planned and 69 were not. Major activities this week included: (1) turning on the Bay B Replacement Heater and (2) the Star Scanner B calibration and its subsequent anomaly investigation and data rate correction. With the beginning of DSN tracking coverage on January 15 at 0730 PST, evidence of an AACS mode change was discovered when telemetry indicated the AACS autonomously had transitioned from the inertial mode (used for the SITURN on January 14) to the cruise mode. "Immediate" review of other AACS telemetry data showed error indications in both the inertial observer and rotor attitude estimation algorithms. The rotor attitude estimation algorithm uses only star-based data to generate an attitude estimate based on SEQID. This estimate is then used by the inertial observer algorithm to update the rotor attitude estimate generated by the gyros. It is pointed out that to transition from inertial to cruise mode requires that the inertial observer "new" gyro-based attitude estimate differ from the "old" gyro-based estimate by > three degrees for four consecutive compare periods (about 20 seconds for the star set in use). Review of rotor attitude estimate data showed a large number of error counts possibly indicating concerns for the star set being used during this phase of the mission. One speculation is the star scanner may be "seeing" some interleaved stars, i.e., several stars of acceptable intensity which are geometrically close together thereby producing extra star pulses. Since no fault response action is taken as a result of anomalous rotor data estimates based on the rotor attitude algorithm, the inertial observer initiated the fault response. AACS personnel are vigorously working this problem to determine the cause and potential solution. Several realtime commands were sent during the evening on January 15 to reconfigure the downlink telemetry rate back to 1200bps to maximize telemetry visibility, to trim the power margin for RPM, and to perform memory readouts of selected locations in AACS and CDS. As of today the spacecraft still remains in the "safed" condition executing sun acquisitions every 12 hours. It is pointed out that to accommodate the necessary actions mentioned above and to monitor the spacecraft performance for the first time in the "safed" state, DSS-43 tracking coverage was diverted from Pioneer 11 (for 1 hour) and Voyager 2 (for 5 hours). Realtime commands were sent on January 19 to reset the AACS catastrophe handler flag to avoid the execution of the "heartbeat" loss algorithm in response to a subsequent AACS faults affecting the SBA, SAS, DEUCE, Star Scanner, I/O or thruster configuration. Execution of "heartbeat" loss is very traumatic and can result in numerous AACS hardware reconfigurations including processors and memories and if executed to completion results in about 70 to 80 AACS PORs. All EV-5 sequence activity was cancelled as a result of executing the system spacecraft safing algorithms. An immediate review of the EV-5 sequence events was performed and it was concluded that there was no concern for spacecraft health or mission events due to cancelling the EV-5 sequence. It is pointed out that the EV-5 sequence would have been operative through February 5. The Project reviewed and approved the spacecraft recovery plan on January 19. To minimize risk and allow the longest available time for the recovery process, the EV-5 sequence will not be restarted. Several events such as RPM flushing, SSI power turn-on/health check, gyro updates, etc. will be performed via realtime commands. 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: Sat, 20 Jan 90 17:44:53 EST From: Kenneth Ng <KEN%ORION.BITNET@vma.cc.cmu.edu> Subject: radiation hazard from retrieving gallieo :Remember that the entire time, the astronauts will be exposed to the :radiation from the RTG's -- a fair amount. In order to stow or :detatch the RTG booms, they would have to get close to the RTG's :themselves. The fuel for the RTG's is Pu238. Pu238 releases 72% of its energy as alpha particles, 28% as beta, and 0.09% as gamma. Alpha you can stop with a piece of paper, beta with aluminium foil, gamma, well that's a pain in the butt. It decays into Np236, significant half life 22 hours. Beta emmission transforms it to Pu236. Again alpha emission, half life 2.7 years, to NP234. NP234 half life 4.4 days decays into U234 with a beta emission, I think. U234 half life 2.48E5 years (I think it'll stay here for a long time :-)), decays alpha particle to Pa232. I'm not typing the rest of the chain since it'll remain U234 for the significant future. The point of all this? The radiation from the RTG's should not be significant to the astronauts should they try to retrieve Galileo. I think they'll have a higher radiation hazard from being outside the Shuttle than from the RTG. Source: Trilinear Chart of Nuclides, January 1957 (yeah I know its ancient, but it was also free). ------------------------------ Date: 20 Jan 90 17:22:13 GMT From: lazlow!pezely@louie.udel.edu (102SMI) Subject: Space Station Freedom to run UNIX The Jan 15th issue of Digital Review had an artical about NASA choosing LynxOS for Space Station Freedom. This article was in the Business & Industry section. LynxOS is a real-time implementation of Unix. (Some Unix systems people would argue that real-time Unix is not true UNIX. Followup to comp.unix.* ) LynxOS was chosen by IBM, which is the systems subcontractor under the primary contractor, McDonnell Douglas Space Systems. I wouldn't mind being the system administrator on a space station... ...that would be one way to get to space. :-) -Daniel Daniel Pezely <pezely@UDel.Edu> (NSFnet) 728 Bent Ln, Newark, DE 19711 USA Comp Sci Lab, 102 Smith Hall, Univ of Delaware, Newark, DE 19716 302/451-6339 ------------------------------ Date: 20 Jan 90 01:54:19 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 01/19/90 (Forwarded) [I've been on travel most of this week, thus Ron Baalke down at JPL has been filling in. Thanks Ron! -PEY] ----------------------------------------------------------------- Friday, January 19, 1990 Audio: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Friday, January 19.... The crew of the STS-32 space shuttle mission will remain in Earth orbit one more day. The delay was forced by predicted ground fog at Edwards Air Force Base. The extension makes the STS-32 mission the longest duration flight in shuttle history. Landing is now scheduled for approximately 3:00 A.M., Eastern time, Saturday. The deorbit burn is scheduled for 1:54 A.M., with NASA Select TV coverage of pre-landing and landing activities beginning at 12:30 A.M. After learning of the delay, crew members set up an echocardiograph device that generates images of the heart and other soft body tissues. In addition...Commander Dan Brandenstein and Pilot Jim Wetherbee will conduct photograpy activities and exercise on the treadmill today. A segment of the right hand solid rocket booster slated for use on the STS-31 discovery mission will be replaced. That decision was made yesterday by NASA and Thiokol Corporation officials. The change is being made because data doesn't show definitely that a required leak check on a nozzle internal joint was properly accomplished. Launch of the Discovery...carrying the Hubble Space Telescope...had been scheduled for late March. The Washington Post reports the delay could be about two weeks. Also at the Cape...the orbiter Atlantis is scheduled to be rolled over to the Vehicle Assembly Building about noon today. Aerospace Daily says recommendations on the early direction of the moon and Mars space initiatives will be sent to President George Bush in two to three weeks. National Space Council Director Mark Albrecht told the Daily, Thursday, some key decisions will be made in the next 30 days relating to the early direction of the program, its thrust and decisions relating to international cooperation. And...two prime flight payload specialists have been named for the International Microgravity Mission aboard the orbiter Columbia now scheduled for December 1990. Dr. Ulf Merbold of the European Space Agency and Dr. Roberta Bondar of the Canadian Space Agency will carry out a wide variety of experiments in the Spacelab module. * * * ----------------------------------------------------------------- Here's the broadcast schedule for public affairs events on NASA Select TV. All times are Eastern. Saturday, January 20.... 12:30 A.M. Coverage begins of pre-landing and landing activities for the STS-32 mission. Landing is scheduled for about 3:00 A.M. A post landing news conference is schedule to begin at approximately 4:15 A.M. Thursday, January 25.... 11:30 A.M. NASA Update will be transmitted. All events and times are subject to change without notice. ---------------------------------------------------------------- These reports are filed daily, Monday through Friday, at 12 noon, Eastern time. ----------------------------------------------------------------- A service of the Internal Communications Branch (LPC), NASA Headquarters, Washington, D.C. ------------------------------ Date: 21 Jan 90 00:30:35 GMT From: zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!uniwa!vaxa!g_ahrendt@tut.cis.ohio-state.edu (Gunter Ahrendt) Subject: Blackbird vs. Foxbat >The Blackbird's altitude capability is pretty definitely much higher than >the records it has actually set, and almost certainly considerably exceeds >that of the Foxbat. (We're talking sustained altitude here, not zoom climbs.) I disagree, a sustained altitude of 24km with a peak of 30km are the Blackbird's excellent figures, i see no reason why it should not have exceeded it's record figures during test & record flights as that is their point. The Foxbat has a peak of 36km thus it's sustained altitude is appropriatly higher. Being developed in response to the RS-70 project, which was the father of the Blackbird. >If one allows craft that drop pieces on the way up (in the way that the >X-15s dropped a B-52 :-) and the X-15A-2 dropped external tanks), then >the X-15A-2 is nowhere near the record holder for either speed or altitude. >The Apollo spacecraft holds the record, with Gemini second and the shuttle >orbiter third. (Before you complain that Apollo and Gemini were not >aircraft, they were in fact lifting bodies at hypersonic speed, and used >their lift to fly fairly complicated reentry trajectories.) International >rules for aircraft records forbid dropping anything except human waste. Oh please, lets not draw thin lines around definitions of Space & Aircraft! Even though the X-15 is fixed wing and rocket powered it is nevertheless an aircraft flying through AIR (thin at that height but still air >-}, whereas the Shuttle et al are spacecraft which travel through SPACE, sure they travel through air to get get their & back again, but this does not make them aircraft! Or does a planes taking off constitute it as an automobile? Please don't take my coment so seriously, it was a small notice that the Foxbat has a greater service ceiling than the Blackbird. ------------------------------ Date: 20 Jan 90 23:41:18 GMT From: dartvax!eleazar.dartmouth.edu!seldon@CS.BU.EDU (Seldon) Subject: Re: Space Station Freedom to run UNIX In article <8833@nigel.udel.EDU> pezely@cis.udel.edu (Daniel Pezely) writes: >I wouldn't mind being the system administrator on a space station... >...that would be one way to get to space. :-) > HEH...can you imagine if they had RN on this system...then we'd start seeing postings with address like: crippen@freedom.nasa.gov Oh well.... -------------------------------------------------------------------------------- seldon@eleazar.dartmouth.edu -- -------------------------------------------------------------------------------- seldon@eleazar.dartmouth.edu "The sky was the color of television tuned to a dead channel..." -William Gibson ------------------------------ End of SPACE Digest V10 #450 *******************