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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
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----------------------------------------------------------------------

Date: 9 Dec 90 15:48:45 GMT
From: sumax!polari![e-mail]  (Charles Radley)
Subject: Re: $$/pound of Freedom vs LLNL (was: ELV Support...)

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] (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| [e-mail]   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![e-mail]  (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![e-mail]  (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![e-mail]  (Henry Spencer)
Subject: Re: Usable Booster Tanks?

In article <[e-mail]> [e-mail] 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| [e-mail]   utzoo!henry

------------------------------

Date: 10 Dec 90 20:14:00 GMT
From: trident.arc.nasa.gov![e-mail]  (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![e-mail]  (John A. Weeks III)
Subject: Re: Translunar/interplanetary shuttle?

In <[e-mail]> [e-mail] 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               [phone]               [e-mail]
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![e-mail]  (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         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  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![e-mail]  (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         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

------------------------------

End of SPACE Digest V12 #656
*******************