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 ; Fri, 14 Dec 1990 02:56:30 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 14 Dec 1990 02:55:58 -0500 (EST) Subject: SPACE Digest V12 #656 SPACE Digest Volume 12 : Issue 656 Today's Topics: Re: $$/pound of Freedom vs LLNL (was: ELV Support...) WUPPE Status for 12/08/90 [AM] (Forwarded) Astro-1 Status for 12/09/90 [0430 CST] (Forwarded) Re: Usable Booster Tanks? WUPPE Status for 12/10/90 [AM #2] (Forwarded) Re: Translunar/interplanetary shuttle? Galileo Update - 11/30/90 Hubble Space Telescope Update - 12/05/90 Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 9 Dec 90 15:48:45 GMT From: sumax!polari!crad@beaver.cs.washington.edu (Charles Radley) Subject: Re: $$/pound of Freedom vs LLNL (was: ELV Support...) In article <1990Dec9.003401.13555@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes: > In article <2853@polari.UUCP> crad@polari.UUCP (Charles Radley) writes: > >... I have never seen a picture of LLNL showing solar > >arrays and unpressurized external palletts which are the main reason > >for Freedom's Truss... > > In case you haven't noticed, Fred is losing its truss in the latest design > revision, now underway. > -- > "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology > points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry Freedom has not lost its truss. nasa is presently trading off two options, a modified version of the present design, keeping the truss, and a new design deleting the truss. Personally I do not see how any startion which is either spun or gravity gradient stablilised, can operate with out a truss, it is needed as a platform for the huge solar panels to track the Sun. If the station is sun pointing, that is the onl alternative where a truss woul,.d not be needed. ------------------------------ Date: 9 Dec 90 19:27:51 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: WUPPE Status for 12/08/90 [AM] (Forwarded) WUPPE STATUS REPORT 13 AM, Dec. 8, 1990 Spacelab Operations Control Center Marshall Space Flight Center Huntsville, AL The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) science team last night completed five scientific observations using the Wisconsin telescope aboard the space shuttle. Those observations included several objects of prime interest to the WUPPE science team: Zeta Tau, a Be supergiant and the only WUPPE primary target observed on last night's shift: L2-Puppis, a cool star with long-period variable features; and NGC 1068, a Seyfert galaxy. Zeta Tau is a rapid rotator. WUPPE astronomers are anxious to compare optical measurements of polarization from the University of Wisconsin's Pine Bluff Observatory with WUPPE polarization data. In the optical, Zeta Tau exhibits a lot of intrinsic polarization. L2-Puppis is a pulsating red star that varies in brightness. Intrinsically very bright, this star has dust ejection episodes which result in a circumstellar cloud of dust. The grains of dust in the cloud are probably the cause of the high levels of polarization observed in visible light. In each of the star's pulsation cycles, cycles which have a period of about 140 days, a shock front travels through the star's atmosphere producing emission lines. One of the strongest emission lines is that of the chemical element magnesium. WUPPE's polarization measurements should provide information on where the gas and dust are located during outbursts. The WUPPE telescope, co-observing with HUT, was able to obtain excellent data on the Seyfert galaxy NGC 1068. At the same time, the UIT instrument was taking ultraviolet photographs of this object, one of great interest to astronomers. Although this object is a HUT primary, it is of interest to the WUPPE science team because of the hypothesis that the galaxy's polarization would increase dramatically in the ultraviolet. Preliminary WUPPE data indicate that this may indeed be the case. Our current understanding of NGC 1068 depends heavily on optical polarization observations. One difficulty is that galaxy background light must be removed from the observations in order to obtain reliable results. This background is much fainter in the ultraviolet. As a result, polarization measurements in the ultraviolet are uncontaminated. The WUPPE instrument continues to perform well and is collecting a wealth of important new scientific data. Sensitivity levels are so good, in fact, that Zeta Tau was almost too bright for WUPPE to observe. Sensitivity levels had to be turned down in order for the WUPPE telescope to collect data on this object. ------------------------------ Date: 9 Dec 90 19:35:28 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Astro-1 Status for 12/09/90 [0430 CST] (Forwarded) Astro-1 Shift Summary Report #22 4:30 a.m. CST Dec. 9, 1990 7/03:40 MET Spacelab Mission Operations Control Marshall Space Flight Center, Huntsville, AL Despite almost three hours of standdown time while the crew performed pre-reentry maneuvers and tests on the orbiter, the Hopkins Ultraviolet Telescope (HUT); Wisconsin Ultraviolet Photo Polarimeter Experiment (WUPPE); and the two Goddard Space Flight Center-managed instruments, the Ultraviolet Imaging Telescope (UIT) and Broad Band X-ray Telescope, are continuing to break new ground in telescope observations from space. Even with the best visible light telescopes, astronomers cannot see a complete picture of the Universe. Visible light is a small part of the electromagnetic spectrum. Stars and other objects often emit more invisible radiation -- radio waves, microwaves, infrared emissions, ultraviolet emissions, X-rays, and gamma rays -- than visible light. From Earth, we can detect some radio and infrared wavelengths, but most radiation is absorbed by the atmosphere and never reaches telescopes on the ground. To detect invisible radiation, astronomers use balloons, rockets, and spacecraft to carry instruments above the atmosphere. Around 8:30 p.m. the three ultraviolet telescopes aboard Columbia completed observing NGC 1851, a high-luminosity globular cluster located in the constellation Columba. Shortly after, UIT and WUPPE acquired M13, a slightly metal-poor globular cluster located in the constellation Hercules. The central region of this cluster is unusually dense, with an average of one star per cubic light-year. Just after 10 p.m., representatives from the four science teams at Spacelab Mission Operations Control, Hunstville, Alabama, briefed the crew aboard Columbia of their progress to date: -- In a late evening science briefing with the crew aboard Columbia, BBXRT Planner Greg Madejski reported they were getting fantastic results, having seen excellent X-rays from all the objects that they wanted to look at so far. According to Madejski, "We have absolutely great results on a lot of extra-galactic sources. We are very much anticipating the analysis of the data that we have (gathered) on magnetic tapes. We simply cannot keep up; there is so much fantastic stuff coming in." -- Johns-Hopkins co-investigator Knox Long reported to the crew successful scientific data gathered about Jupiter, G191-B2B, the Crab Nebula, Cygnus Loop, and UX UMa. -- According to UIT astronomer Susan Neff, "We think we are getting great data." Neff reported "nice long observations on lots of our prime targets. We're greedy. We would always like more. But what we are getting should keep us off the streets for a long time. We have gotten two really good nights on M31. We've gotten four great nights on NGC 1399 -- the Fornax Cluster. That data is going to keep people real happy." -- WUPPE's Principle Investigator Art Code reported to the crew the success of several of their prime targets. "We've got a number of real good interstellar probes. And among the things we see is confirmation of an identification that Ted Stecher [principle investigator for the UIT team] made 25 years ago: the 2,200 Angstrom extinction bump [seen in interstellar dust observations] is due to graphite. We got great polarization measurements on rapid rotators, magnetic white dwarfs, Wolf-Rayet stars like Regina's EZ Canis Majoris, massive super-giant like P Cygni which throws off mass periodically. To the astronomers aboard the Shuttle, Art Code said, "We're really grateful for the fantastic job you've done to help us get this first UV polarization in space. As an old-fashioned astronomer, I'm really pleased to see that you are doing old-fashioned astronomy by manually pointing." The HUT, UIT, and WUPPE acquired Abell 426 at approximately 12:30 a.m. Abell 426 is a cluster of galaxies centered in the constellation Perseus. Tightly scheduled within a short observing window between two orbiter maneuvers, the three telescopes were able to lock onto their joint target within four minutes of the orbiter achieving the necessary attitude. With the cancellation of a scheduled orbiter waste water dump, HUT and UIT were able to schedule a 1:45 a.m. observation of Abell 665, a cluster of galaxies emitting large quantities of X-rays. The two telescopes co-observed HD 37903, an observation hoping to probe into the nature of interstellar dust. This target, a B-type star, illuminates the reflection nebula NGC 2023. A reflection nebula contains dust grains that scatter light, producing a brilliant illumination in the cloud. ------------------------------ Date: 10 Dec 90 18:36:07 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Usable Booster Tanks? In article <5274.276386f9@cc.nu.oz.au> mdrlc1@cc.nu.oz.au writes: >what are the constraints on using the main external tank >from each shuttle launch?. They are big and light and will reenter quickly if placed in a low orbit and left to themselves. At the very least, something must be done to place them in a minimum-air-drag orientation, because the attitude they naturally assume -- tank axis pointing toward the Earth -- is the worst possible. They will be punctured fairly quickly by space debris, unless some sort of shield is placed around them. The insulation on the outside will "popcorn" in vacuum and add greatly to the space-debris problem unless it is contained somehow; the same shield needed to prevent debris impacts may suffice to do this. Putting them into orbit is no longer free -- the shuttle no longer flies a deliberate "dip" maneuver to jettison the tank -- although the cost is modest for low orbits. As a matter of political policy, NASA will not place an external tank into orbit unless it is equipped with a highly reliable system to de-orbit it at a controlled time if/when necessary. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 10 Dec 90 20:14:00 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: WUPPE Status for 12/10/90 [AM #2] (Forwarded) UNIVERSITY OF WISCONSIN-MADISON WUPPE STATUS REPORT NO. 18 AM,MONDAY,DECEMBER 10, 1990 The University of Wisconsin telescope aboard the Shuttle Columbia ceased operations this morning after the decision was made to land the orbiter tonight. The telescope door for the Wisconsin Ultraviolet Photo-Polarimeter Experiment was closed at 9:19 a.m. CST. The last observation made by the Wisconsin telescope was Comet Levi. Unexpectedly, the Wisconsin telescope was able to obtain significant from the comet. It was thought that the comet would be too faint for the Wisconsin telescope to detect. The WUPPE science team is interested in seeing how light is polarized as it is scattered off of the dust surrounding the nucleus of the comet. WUPPE observations may help determine the chemical composition of cometary dust. They may also tell astronomers how similar cometary dust is to interstellar dust. This is of interest because it may provide new insights to the birth of our solar system. Wisconsin astronomers said that despite computer problems early on in the mission, the Wisconsin telescope performed far better than expected. Its sensitivity levels were greater than anticipated, meaning even abbreviated observations would yield useful scientific information. ------------------------------ Date: 9 Dec 90 20:55:59 GMT From: sdd.hp.com!news.cs.indiana.edu!msi.umn.edu!cs.umn.edu!kksys!wd0gol!newave!john@ucsd.edu (John A. Weeks III) Subject: Re: Translunar/interplanetary shuttle? In crockwel@aludra.usc.edu writes: > you think every secretary in the air force knows how the stealth bomber > works??? i know one person who works for the air force who claims that > they didn't have a plane nick-named 'blackbird'. I am under the impression that the name "blackbird" is stricly unofficial. I don't think that the SR-71, F-117, or B-2 programs have official names. -john- -- =============================================================================== John A. Weeks III (612) 942-6969 john@newave.mn.org NeWave Communications ...uunet!rosevax!tcnet!wd0gol!newave!john =============================================================================== ------------------------------ Date: 11 Dec 90 03:55:39 GMT From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@apple.com (Ron Baalke) Subject: Galileo Update - 11/30/90 GALILEO STATUS REPORT November 30, 1990 Yesterday, the Galileo spacecraft completed planned calibration activities for the remote science instruments and the Magnetometer instrument. Today, commands will be sent to power on the relay radio hardware oscillators in preparation for Probe checkout activities on December 4. No spacecraft sequencing activity is planned over the weekend on December 1 and 2. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | 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 04:23:43 GMT From: snorkelwacker.mit.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@bloom-beacon.mit.edu (Ron Baalke) Subject: Hubble Space Telescope Update - 12/05/90 HST STATUS REPORT December 5, 1990 Controllers of the Hubble Space Telescope (HST) expect to resume Science Verification on Sunday, December 9, after the failure of a redundant gyro placed the spacecraft in safe mode for several days. HST entered "safe" mode Monday, December 3, at 09:08 EST. The "safing," officially called a software sunpoint safemode, occurred shortly after the spacecraft had passed through the deepest part of the South Atlantic Anomaly, the area over which the Earth's radiation belts pass relatively close to the surface. HST had just completed a successful guide star acquisition. First indications of a problem began at 8:05 A.M., when controllers noticed some oscillation in the spacecraft. A few seconds later, the spacecraft lost lock on the guide star, and the gyros shifted operating modes. At the same time, the spacecraft began a high roll rate (60 arc seconds per second). The gyros sensed something was wrong, causing the software to turn off the No. 6 gyro and put the spacecraft into a three-gyro configuration. The spacecraft has six gyros, but only uses four actively for normal operations. At the time of the incident, gyros 3, 4, 5 and 6 were in operation. At 8:13 A.M., a scheduled loss of signal with the Tracking and Data Relay Satellite (TDRS) occurred but at 08:24 the expected acquisition of signal did not occur, indicating that either the HST antennas were not pointing at TDRS or the spacecraft had entered safe mode. Data that was later replayed indicated that at 09:08 the spacecraft had failed a battery rate of charge test, and the HST autonomously went into the software sunpoint safemode as it is designed to do. Preliminary failure analysis indicates the HST probably lost its null signal to gyro 6 and, therefore, probably suffered a failure in the circuitry in the gyro 6 electronics control unit or in the wiring between the two. Both units are Orbital Replacement Units (ORUs) and can be replaced on the 1993 servicing mission. Attempts to reset gyro 6 on Tuesday, December 4 were unsuccessful. About 20:00 Tuesday, one of the two backup gyros, No. 2, was activated. It has been introduced into HST's control system and recovery from safe mode has begun. Appropriate housekeeping and alignment activities related to the activated gyro will take place over the next few days, and Science Verification activities are expected to resume Sunday, December 9. Goddard Space Flight Center has established a formal failure review board to define the most probable cause of the failure and to provide recommendations concerning further actions. Planning has begun to permit the inclusion of a replacement pair of gyro ORUs on the 1993 servicing mission. Status of HST instruments and other issues: GODDARD HIGH RESOLUTION SPECTROGRAPH (GHRS): Investigated the chromosphere of Alpha Tau, brightest star in the constellation Taurus. Though larger and brighter than our Sun, it is cooler. Purpose of the test was to observe emission lines from ionized carbon at a wavelength near 2325 angstroms. HIGH SPEED PHOTOMETER (HSP): A focus and aperture mapping test was conducted successfully. FAINT OBJECT SPECTROGRAPH (FOS): Conducted a Red Side Absolute Photometry test which ran "perfectly" on the second of three targets. The team is looking for reasons this test works on the Red Side but not on the Blue Side, referring to the blue and red RendsS of the spectrum of visible light. WIDE FIELD/PLANETARY CAMERA (WF/PC): Completed photometry of a Large Magellanic Cloud Young Cluster. Test provides realistic data for stellar photometry over a range of crowding. ASTROMETRY: A Science Assessment Observation (SAO) for duplicity among Hyades' stars was performed with no apparent problems. SPHERICAL ABERRATION: Tests required by the Hubble Aberration Recovery Program (HARP) to characterize fully the Optical Telescope Assembly (OTA) were completed just before HST entered safe mode. From this information, the final optical prescription for the replacement instruments will be derived. The prescription for the Wide Field/Planetary Camera-2 is due at JPL by the middle of December. SOLAR ARRAYS: On November 28 controllers at Goddard uplinked software known as the Solar Array Gain Augmentation (SAGA), designed to attentuate the 0.1Hz disturbances being transferred into the body of the HST by the European Space Agency-developed solar arrays. The disturbance, commonly referred to as a "jitter," takes place when the HST moves from daylight to darkness and vice versa. The SAGA software is aimed at offsetting the vibration in the HST, which was making the gyros switch operating modes and causing the HST to lose lock on its guide stars. Initital testing of the SAGA software was encouraging. In tests of up to 11 hours, HST's gyros had not switched from the low to the high mode. Significant damping of the 0.1Hz disturbance was noted, although a small oscillatory disturbance in the roll axis was observed in an activation just prior to entering the safe mode. That disturbance is being evaluated. March continues to be the target date for all software efforts to correct the solar array jitter. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ End of SPACE Digest V12 #656 *******************