Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_6/V12_641.TXT

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Subject: SPACE Digest V12 #641

SPACE Digest                                     Volume 12 : Issue 641

Today's Topics:
      Instrument Pointing System Status for 12/02/90 (Forwarded)
             Re: Fueling Columbia
      Astro-1 Status for 12/04/90 [2130 CST] (Forwarded)
       Solar System Stability (was Re: * SpaceNews 03-Dec-90 *)
   NASA's Manned/Unmanned Track Record (Re: Another Russian first)
        HUT Status for 12/03/90 [1130 CST] (Forwarded)
      Good Bye  (Quite possibly my last posting from this site)
              Re: Another Russian first
       BBXRT Status for 12/04/90 [1430 CST] (Forwarded)

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription notices,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: 5 Dec 90 00:24:45 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Instrument Pointing System Status for 12/02/90 (Forwarded)


         STS-35/Astro-1  IPS Status Report
         Mission Control Center, Houston
         9:30 p.m. CST, Sunday, Dec. 2, 1990


         Flight controllers were in the final stages this evening of
         verifying a software patch that will set the stage for automated
         target acquisition with the Instrument Pointing System.  That
         device, which goes by the acronym IPS, houses several of the
         primary astronomical instruments being trained toward deep space
         on this science flight.

         The IPS uses star trackers and gyroscopes in its automatic mode
         in order to lock on to pre-programmed stars.  During the initial
         attempts to calibrate the system and begin taking science data in
         the automatic mode, controllers found that one of the IPS star
         trackers would not recognize and lock on to dimmer stars, as it
         had been programmed.  The software patch therefore became
         necessary in order to direct the device to lock onto brighter--or
         higher magnitude--stars.

         Meanwhile, the Orbiter Columbia itself continues to perform
         flawlessly, with no systems problems currently being tracked by
         flight controllers in Houston.  The vehicle is in a 190 by 188
         nautical mile orbit inclined 28.5 degrees to the equator.  The
         Columbia completes one orbit of the Earth every 1 hour and 31
         minutes.

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

Date: 4 Dec 90 22:25:38 GMT
From: swrinde!elroy.jpl.nasa.gov!wciu!abode![e-mail]  (Eric C. Bennett)
Subject: Re: Fueling Columbia

In article <[e-mail]> [e-mail] writes:
>My girlfriend asked a good question the other day, while we were waiting to
>watch the shuttle launch on TV:  Did they fill up Columbia's tanks before
>the federal gas tax went up 5 cents/gallon at 1-Dec-1990 00:00?  Think how
>much they would save!   :-)  :-)

Well, if the tax applies to liquid hydrogen I think the Shuttle program is
going to have to pay a lot more for launches! :)

Eric
1
--
     Eric C. Bennett     uucp: {elroy|cit-vax}!wciu!abode!eric
     El Monte, Ca    Internet: [e-mail]

If you can read this you aren't looking through the hubble space telescope!

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

Date: 5 Dec 90 18:09:17 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Astro-1 Status for 12/04/90 [2130 CST] (Forwarded)


      Astro 1 Shift Summary #09
      9:30 p.m. CST, December 4, 1990
      2/20:40 MET
      Spacelab Mission Operations Control
      Marshall Space Flight Center


      Observations of significant astronomical targets were coming with
      increasing regularity during the afternoon and early evening hours
      of Tuesday, the third day in the Astro-1 mission.

      "We have an observatory that's really coming alive now," said
      Astro-1 Mission Scientist Dr. Ted Gull approximately midway through
      this period.  "I can smile now."

      A key milestone resulting in this type of comment from mission
      management and science team members was the marked improvement
      during this period in the Astro-1 payload's capability to execute
      automatic stellar acquisitions.  The improvement in acquisition
      procedures came thanks to persistent efforts by members of the
      Astro-1 ground support teams, who sent up to Columbia a series of
      successively more refined calibrations to the payload's sensitive
      star-tracker optics.

      At 4:00 p.m. (CST), crewmembers Sam Durrance and Jeff Hoffman
      reported that the improved star-tracker geometry enabled them to
      perform one automatic target acquisition followed immediately by
      another, with no intervening recalibration.  Alternate Payload
      Specialist Ken Nordsieck, in the Spacelab Mission Operations Control
      Facility, noted that the achievement resulted in the second of the
      two observations being "about as nominal an observation as we've
      done."  That comment applied to the three ultraviolet instruments
      mounted on Spacelab's Instrument Pointing System (IPS).  Pointing
      stability was still below specifications and, because control of
      Spacelab, the IPS and the experiments is still being done on a
      single computer terminal, acquisitions continued to require longer
      times than expected.  However, both problems were expected to
      improve, increasing the quality and quantity of ultraviolet science
      data.

      There was also major progress for the separately pointed and
      controlled fourth instrument aboard Columbia, the Broad Band X-Ray
      Telescope (BBXRT).  By around 5 p.m., Principal Investigator Dr.
      Peter Serlemitsos reported that a successful alignment had been
      completed between the X-ray telescope and its mounting mechanism,
      the Two-Axis Pointing System.  That accomplishment marked a
      significant victory over previous drift problems, appearing to clear
      the way for the BBXRT team to press on with their science
      observation program.  During this period, the X-ray telescope took
      science data during observations of the Crab Nebula (NGC 1952 in the
      New General Catalogue) and the binary star system Cygnus X-3.

      Several key observations were made during this period with the three
      ultraviolet telescopes, among them:

           o  The globular cluster M92, which is a cluster of some 100,000
              stars about 25,000 light years distant from Earth.  The
              cluster contains numerous very hot, old stars which produce
              ultraviolet radiation.

           o  The star Theta Muscae, a Wolf-Rayet star which exhibits a
              very strong stellar wind.

           o  And the well-known supernova remnant Cygnus Loop.  The
              supernova which was the source of this remnant exploded some
              50,000 years ago.

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

Date: 5 Dec 90 23:33:38 GMT
From: dweasel![e-mail]  (Loren Petrich)
Subject: Solar System Stability (was Re: * SpaceNews 03-Dec-90 *)


    Concerning solar system stability, it must be conceded that
this is not a completely solved problem.

    Perturbation theory techniques are the traditional way to
evaluate this problem. However, use of them depends on dropping
higher-order terms, and there is the problem of how much these
contribute to the final results. In particular, if there is a
near-commensurability in some of the orbit periods, then that will
magnify the effect of whatever terms in which it causes a
near-cancellation of the rate of change. Example: if there are two
objects, 1 and 2, of which object 1 has a mean angular velocity twice
that of object 2, then terms containing expressions like:

    l1 - 2*l2

where l1 and l2 are the mean longitudes of the two objects, will
change slowly and may even produce big oscillations in l1 and l2.

    Since most perturbation-theory analyses ultimately involve
averaging over orbit positions, resonance terms like the example
mentioned above are a serious difficulty, unless they can be
identified.

    Even in that case, one may approach the limits of analytical
tractability, and have to resort to numerical integration, which can
be done directly on the coordinates of the objects. I note that orbit
elements can be thought of as "coordinates" in this context, though
their equations of motion are more complicated than the equations of
motion for positions and velocities.

    Direct integration of the positions and velocities also has
the advantage of keeping all the terms, as it were, as opposed to
doing integration for the orbit elements with a truncated perturbation
series, due to the missing-term problem. However, integrating orbit
elements can cover a much longer time range for a truncated
perturbation series, because the orbit-variation timescale is usually
much greater than the orbit periods.

    Actual results? It appears that some of the objects in the
Solar System move chaotically. Saturn's satellite Hyperion is known to
tumble chaotically, for instance. And numerically integrating Pluto's
orbit reveals it to change chaotically. There is even evidence for
chaos in the motions of the four big planets -- Jupiter, Saturn,
Uranus, and Neptune. However, the "size" of the region of chaos is
still uncertain. If it turns out to be small, then the motions of the
planets are predictable within that region, and it may even be that
the Solar System is stable over timescales of billions of years
despite the weak chaos in the motions of the planets. More research on
this question will certainly be needed.


$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Loren Petrich, the Master Blaster: [e-mail]

Since this nodename is not widely known, you may have to try:

[e-mail]

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

Date: 4 Dec 90 04:35:49 GMT
From: rochester!sol![e-mail]  (Brian Yamauchi)
Subject: NASA's Manned/Unmanned Track Record (Re: Another Russian first)

In article <[e-mail]> [e-mail] (Steve "il-Manhous" Norton) writes:

   [e-mail] (Brian Yamauchi) writes:

   ...
   >First Jupiter probe -- Pioneer 10
   >First Saturn probe -- Pioneer 11
   >First Uranus probe -- Voyager 2
   >First Neptune probe -- Voyager 2

   How about :
    First billion dollars wasted on broken telescopes -- Hubble
b    First spacecraft explosion to kill all on board due
      to ground problems (faulty management) -- Challenger
    First spacecraft launch delayed more than six months -- Columbia

So here's an interesting question:  Why are NASA's unmanned missions
so successful while NASA's (recent) manned missions have suffered from
so many setbacks?

It's not that manned missions are harder -- the Soviets seem to have
the opposite problem (unmanned failures despite manned successes).

It's not just funding politics -- unmanned missions suffer from the
same Congressional squabbles as manned missions -- and usually end up
with less money.

Is it just the complexity of the shuttle?

Is it because JPL is run by Caltech instead of NASA?  But Pioneer and
Viking were both coordinated by Ames...

So, is the problem with JSC/MSFC/KSC?  With the bureaucracy in
general?  And if so, have JPL and Ames managed to stay free of the
bureaucracy or do they get work accomplished in spite of it?
--
_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Computer Science Department
_______________________________________________________________________________

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

Date: 4 Dec 90 23:54:27 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: HUT Status for 12/03/90 [1130 CST] (Forwarded)


         HUT Status Report
         12/3/90
         11:30 a.m. CDT

         The Hopkins Ultraviolet Telescope team received "first light" data
         from the telescope at 11:30 a.m.  The first spectrum was produced from
         ultraviolet emissions in the Earth's upper atmosphere.

         The observation was important for three reasons:

         1:  HUT's first light was the first science calibration observation
         made by any of Astro-1's instruments.

         2:  Because HUT must "look" through this atmosphere to observe
         objects, this spectrum must be subtracted from any spectra collected
         for stars, galaxies, etc.

         3:  HUT team scientists will analyze the spectrum and compare it to
         earlier observations or the Earth's air glow, or upper atmosphere, to
         determine the effect the Sun has on the Earth's atmosphere.  This
         spectrum was the highest quality observation ever made in the far
         ultraviolet for Earth's atmosphere.

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

Date: 6 Dec 90 02:09:41 GMT
From: agate!linus!philabs!briar![e-mail]  (Robert Casey)
Subject: Good Bye  (Quite possibly my last posting from this site)

I'm afraid that this may be my last posting.  Philips is having layoffs, and I
might get canned.  I liked having access to these newsgroups, and would like
to regain access at some other site.

If anyone knows of anyone looking for a person who knows about HDTV,
NTSC, video, digital signal processing, high speed digital logic
design, have them call me at 201-261-4066.  Also, point any and all
headhunters my way.  I have 11 patents.

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

Date: 3 Dec 90 23:09:56 GMT
From: sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!uupsi!cci632!ritcsh!ultb!ritvax.isc.rit.edu![e-mail]  (DAVIS, SW)
Subject: Re: Another Russian first

In article <[e-mail]>, [e-mail] (Frank G. Dahncke) writes...
>Now the USSR even has had the first paying passenger in a spacecraft.
>Actually, I would have expected this feat to be performed by the US.
>Are there any other spaceflight "firsts" that the USA has achived exept
>for the first man on the moon ?
>
>                              Curious,
>
>                                   Techno
>
>--
>| [e-mail] ||| Please do not e-mail from outside Germany ! |
>| [e-mail]   / | \ Hardcore ST user !  ====================== |
>| Nothing that's real is ever for free, you just have to pay for it sometime. |
>|                                        (Al Stewart)                         |


    Most definitely! We are the first (and still the only) to send probes to
the outer planets of Jupiter,Saturn,Uranus,and Neptune. We had the first space
station (Skylab),and of course the first shuttle launch.


              Scott

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

Date: 5 Dec 90 05:21:01 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: BBXRT Status for 12/04/90 [1430 CST] (Forwarded)


         BBXRT Status Report #03
         2:30 p.m. CST Dec. 4, 1990
         Spacelab Mission Operations Control
         Marshall Space Flight Center,
         Huntsville, AL


         The BBXRT and its Two-Axis Pointing System (TAPS) were
         co-aligned at 5:30 a.m.  CST today and shortly after BBXRT
         locked on its first x-ray target, the bright star Capella.

         "With the kind of observations we have planned we should do
         tremendous science," reported Goddard's Dr. Peter
         Serlemitsos, principal investigator.

         This morning's observation gives scientists the temperature
         and the element abundances of Capella.

         Serlemitsos described the BBXRT's resolution as excellent and
         added that the 300 seconds of data collected so far has
         revealed information not seen in previous observations.

         BBXRT team members are currently working to fine tune the
         TAPS and expect to be pointing routinely to their sources by
         this evening.

         BBXRT and TAPS were developed and are operated from Goddard
         Space Flight Center in Greenbelt, MD.

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

End of SPACE Digest V12 #641
*******************