Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_6/V12_629.TXT

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Subject: SPACE Digest V12 #629

SPACE Digest                                     Volume 12 : Issue 629

Today's Topics:
           Re: space news from Oct 10 AW&ST
              Re: Photon engine
          NASA Prediction Bulletins:  Space Shuttle
          WUPPE Status for 12/05/90 [PM] (Forwarded)
             Re: SPACE Digest V12
               Fluorine/ammonia engines
          Re: Status of Astro at 2/11:00 MET
             Re: * SpaceNews 03-Dec-90 *
      Astro-1 Status for 12/04/90 [1750 CST] (Forwarded)
                 Re: Astro-2
       BBXRT Status for 12/05/90 [1600 CST] (Forwarded)
          NASA Prediction Bulletins:  Space Shuttle
    Re: $$/pound of Freedom vs LLNL (was: ELV Support...)

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 04:41:06 GMT
From: zephyr.ens.tek.com!tektronix!sequent!crg5![e-mail]  (Nick Szabo)
Subject: Re: space news from Oct 10 AW&ST

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
>Wolfgang Wild, head of DARA [the German space agency], calls for serious
>stretchout of Hermes and Columbus, on the grounds that the current budgets
>and schedules are seriously unrealistic.
>...

Apologies in advance for blatant nationalism:  I'm glad the Europeans
are mimicking our failures as well as our successes.  Ariane had us
scared for a few years.  :-)

>Letter from the External Relations directory of NASDA, saying that limits
>on photography during AW&ST's visit to Tanegashima were due to safety
>regulations related to the engine test then being readied, not to desire
>to limit technology transfer.  AW&ST replies that this reason/excuse was
>not mentioned at the time.

Gosh, now we know what caused the H2 failure.  Somebody wasn't careful
with the auto-focus.  :-) :-) :-)

Nick Szabo
[e-mail]

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

Date: Mon, 3 Dec 90 19:03:22 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Photon engine


>From: swrinde!zaphod.mps.ohio-state.edu!van-bc!ubc-cs!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
>Subject: Re: Photon engine

>In article <[e-mail]> [e-mail] (John Roberts) writes:
>>I can think of one exception to this rule. If you use a "pure" energy source
>>such as antimatter, and if you have a certain mass budget for fuel plus
>>reaction mass, then you get marginally more thrust by dedicating the whole
>>mass to equal quantities of matter and antimatter, to be blasted out as
>>photons, than by setting aside some additional normal matter as reaction
>>mass...

>Uh, the matter/antimatter reaction does not yield photons.  Not immediately.
>If you are reacting matter and antimatter, what you are blasting out is
>mostly either pions or muons, depending on the size of your engine.

>...In the long run, everything ends up as gamma rays and neutrinos, but
>fortunately for antimatter propulsion, a lot of that happens long after
>the stuff leaves the engine.  Charged particles are *much* easier to
>work with.

>"The average pointer, statistically,    |Henry Spencer at U of Toronto Zoology
>points somewhere in X." -Hugh Redelmeier| [e-mail]   utzoo!henry

Well, I didn't actually *say* how long it would take the energy to get out.
React the matter and antimatter inside a huge chunk of radiation-absorbing
refractory material, and I bet most of the intermediate particles would break
down inside. Of course the neutrinos would still get out, and there doesn't
seem to be any way of directing them for propulsion. Any idea of (a) the
percentage of energy wasted in this way, or (b) the impulse per Joule-
equivalent of neutrinos as compared with photons? For (b), I have a sneaking
suspicion that they would be the same.

Granted, a "conventional" antimatter engine doesn't work this way, but then
it presumably doesn't use a 50-50 mix either. :-)  Could you please post a
general description of a more workable antimatter engine?
      John Roberts
      [e-mail]

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

Date: 5 Dec 90 23:43:12 GMT
From: ncis.tis.llnl.gov!blackbird![e-mail]  (TS Kelso)
Subject: NASA Prediction Bulletins:  Space Shuttle


The most current orbital elements from the NASA Prediction Bulletins are
carried on the Celestial BBS, [phone], and are updated several times
weekly.  Documentation and tracking software are also available on this
system.  As a service to the satellite user community, the most current
elements for the current shuttle mission are provided below.  The Celestial
BBS may be accessed 24 hours/day at 300, 1200, or 2400 baud using 8 data
bits, 1 stop bit, no parity.

STS 35
1 20980U 90106  A 90339.50869458  .00040487  00000-0  28788-3 0    95
2 20980  28.4663 341.6124 0009644 315.7347  44.5240 15.72322012   514
--
Dr TS Kelso                           Assistant Professor of Space Operations
[e-mail]          Air Force Institute of Technology

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

Date: 6 Dec 90 03:49:22 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: WUPPE Status for 12/05/90 [PM] (Forwarded)


      WUPPE Status Report No. 8
      PM, Wednesday, Dec. 5, 1990
      Spacelab Mission Operations Control
      Marshall Space Flight Center,
      Huntsville, AL


      Wisconsin astronomers using the WUPPE telescope aboard the Space
      Shuttle Columbia today took observations of six objects, including
      the WUPPE primary object P Cygni, a supergiant star.

      P Cygni was observed for approximately 33 minutes by WUPPE and is an
      important object for the WUPPE team because of abundant ground-based
      data available from the University of Wisconsin's Pine Bluff
      Observatory.  Approximately 24 nights of optical spectropolarimetry
      have been taken on this particular object.  P Cygni is being
      observed during the Astro mission by astronomers at Pine Bluff and
      also by the International Ultraviolet Explorer satellite.

      In the 17th century, P Cygni, located in the constellation Cygnus
      the Swan, was observed to have undergone a large increase in
      brightness.  But for the last 100 years P Cygni has been in a
      relatively quiet phase, exhibiting little evolutionary change.
      Ground and space-based observations now indicate that this star
      ejects material at irregular intervals and appears to be in a
      constant state of activity.  This ejection of stellar mass is of
      interest to astronomers because it will provide insight into the
      evolution of hot massive objects.  Astronomers would like to know if
      the material is ejected uniformly in the form of a shell; if it is
      ejected in so-called plumes; or if it is ejected in the form of
      "blobs."

      The spectropolarimetry data from WUPPE will provide information on
      the distribution of material in the circumstellar environment and on
      the mass loss mechanism.

      The WUPPE instrument is still performing well and no problems with
      the telescope have been reported by the WUPPE science team.

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

Date:         Thu, 6 Dec 1990 06:24 IST
From: Moshe Solow <[e-mail]>
Subject:      Re: SPACE Digest V12
To: <[e-mail]>

PLEASE PLEASE PLEASE !!!!
Remove me from the list. Thank you  I have sent unsubscribe several times
to no avail.

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

Date: 3 Dec 90 23:29:12 GMT
From: swrinde!zaphod.mps.ohio-state.edu!van-bc!rsoft!mindlink![e-mail]  (Bruce Dunn)
Subject: Fluorine/ammonia engines

> [e-mail] writes:
>
> Don't know if this is old news or what, but I attended the "Soviet Space"
> exhibit at the Museum of Science here in Boston a few months back.  One
> of the items on display was an experimental engine designed to run florine
> and ammonia (I think it was ammonia).  The writeup said it did not become
> an engine to be used on a regular rocket, but they did learn a lot from the
> research.  They didn't say what they learned.
>
> Flourine and ammonia?  Whew!  Tricky stuff.
>
> Jim Cook


     Yes, I am sure that you heard right.  Fluorine is a very powerful oxidizer
and has a high liquid density making it attractive for rocket propulsion.  It
does not perform well with fuels containing carbon (unless there is also some
oxygen in the propellant or fuel to oxidize the carbon).  The preferred fuel
with fluorine is hydrogen or of all things liquid lithium (both give about the
same exhaust velocity).  To avoid liquid hydrogen, liquid ammonia (NH3) is also
quite usable, and gives an exhaust velocity which is about 90% of that of
fluorine and liquid hydrogen.
     Fluorine can readily attack metals and under the right circumstances will
oxidize an metal engine just as easily as it does a metal fuel (lithium).
However, with care, metal surfaces will form a fluoride coating that will
prevent further fluorine attack.  RL-10 engines designed for oxygen and
hydrogen have been run on fluorine and hydrogen with little modification.  If
things go wrong however, they go wrong badly - picture a running engine with
two exhaust streams, one the normal one and one at right angles where the
fluorine has decided to oxidize the metal wall of the combustion chamber rather
than the fuel.
     Trivia question: what chemical propellant combination has the highest
exhaust velocity?

Answer 1:  Hydrogen and oxygen     - wrong
Answer 2:  Hydrogen and fluorine   - better but still wrong
Answer 3:  Hydrogen and lithium and fluorine tripropellent mix - right

--
Bruce Dunn   Vancouver, Canada    [e-mail]

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

Date: 4 Dec 90 23:48:57 GMT
From: sun-barr!newstop!texsun!csccat![e-mail]  (Jack Hudler)
Subject: Re: Status of Astro at 2/11:00 MET

In article <[e-mail]> [e-mail] (Greg Hennessy) writes:
>There was an estimate on the nature of the error in the star tracker.
>The star tracker is apparently more sensitive then expected, so more
>stars were being seen.
Where have I heard this before! :-)
--
Jack         Computer Support Corporation        Dallas,Texas
Hudler        Internet: [e-mail]

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

Date: 5 Dec 90 13:27:43 GMT
From: [e-mail]  (Bill Newman)
Subject: Re: * SpaceNews 03-Dec-90 *

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Franklin Antonio) writes:
>>So, the basic work was done 371 years ago!  This is one of the humbling things
>>about celestial mechanics...
>
>Kepler is not the really humbling example in celestial mechanics.  That
>honor goes to Isaac Newton, not much later.  After deducing that gravity
>followed an inverse square law, he explored the consequences of that
>(including deriving Kepler's Laws) so thoroughly that the greatest
>mathematicians of the next two centuries basically just added footnotes
>to his work.

Newton certainly killed the 2-body gravitational problem, but many
aspects of the many-body problem were better understood 200 years
after his death than at his death.  In particular, while it took
more than 200 years to come up with the modern theory of stability,
200 years of perturbation theory revealed enough to make it plausible that
the solar system could be stable for billions of years
without invoking the hand of God to fix things up.

  Bill Newman

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

Date: 5 Dec 90 18:05:01 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Astro-1 Status for 12/04/90 [1750 CST] (Forwarded)


      Astro 1 Mission Report #18
      5:50 p.m. CST, December 4, 1990
      2/16:59 MET
      Spacelab Mission Operations Control
      Marshall Space Flight Center

      "We have an observatory!" beamed an enthusiastic Ted Gull, Astro 1
      Mission Scientist during the afternoon mission briefing at Spacelab
      Mission Operations Control in Huntsville, Alabama.

      The news reaffirms the improving status of the mission through
      completed science observations and control of the Instrument
      Pointing System. Team scientists expressed delight in their findings
      so far and are anxious to share future discoveries in upcoming
      briefings.

      "It's come alive and we've started to get some science results,"
      added Gull, as he reaccounted the day's activities which included
      the successful acquisition of several targets. Astro scientists
      Stephen Holt of the Broad Band X-Ray Telescope and Arthur Code of
      the Wisconsin Ultraviolet Photo-Polarimeter teams were also present
      at the mission briefing to share their earlier findings.

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

Date: 6 Dec 90 01:52:37 GMT
From: [e-mail]  (Michael S. Gull)
Subject: Re: Astro-2


    I think there were only 7 missions originally planned, but I could be
 wrong.  At the time of the Challenger disaster, I think there were 5 still
 committed to, and after the ensuing confusion, the number was pared down to 3.
    Astro-1 was supposed to be the flight after Challenger, with the principle target being Halley's Comet.  As a result, if you remember, the US had no observation craft in place for Halley.


                            MikeGull

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

Date: 6 Dec 90 03:47:34 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: BBXRT Status for 12/05/90 [1600 CST] (Forwarded)


         BBXRT Status Report #04
         4 p.m. CST Dec. 5, 1990
         Spacelab Mission Operations Control
         Marshall Space Flight Center,
         Huntsville, AL


         "We started observing regularly last night and have been
         observing ever since," said BBXRT Principal Investigator Dr.
         Peter Serlemitsos of Goddard Space Flight Center.

         All coalignment problems seem to be resolved as of late
         yesterday and since that time the BBXRT has observed more
         than a dozen targets.  A small (about 4 arc minutes) drift
         rate has not yet been resolved.

         Plans this evening include observing Supernova 1987A, located
         170,000 light years away in the Large Magellanic Cloud.
         BBXRT was added to the STS-35 mission after the appearance of
         SN 1987A in February 1987 in order to obtain vital scientific
         information about the Supernova.

         BBXRT was developed and is managed by GSFC in Greenbelt, MD.

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

Date: 3 Dec 90 22:35:53 GMT
From: ncis.tis.llnl.gov!blackbird![e-mail]  (TS Kelso)
Subject: NASA Prediction Bulletins:  Space Shuttle


The most current orbital elements from the NASA Prediction Bulletins are
carried on the Celestial BBS, [phone], and are updated several times
weekly.  Documentation and tracking software are also available on this
system.  As a service to the satellite user community, the most current
elements for the current shuttle mission are provided below.  The Celestial
BBS may be accessed 24 hours/day at 300, 1200, or 2400 baud using 8 data
bits, 1 stop bit, no parity.

STS 35
1 20980U 90106  A 90337.78402777  .00035775  00000-0  25599-3 0    79
2 20980  28.4679 354.1588 0008868 290.3029   7.7376 15.72170789   249
--
Dr TS Kelso                           Assistant Professor of Space Operations
[e-mail]          Air Force Institute of Technology

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

Date: 4 Dec 90 03:01:38 GMT
From: sumax!amc-gw!thebes!polari![e-mail]  (Charles Radley)
Subject: Re: $$/pound of Freedom vs LLNL (was: ELV Support...)



-
You say LLNL orbits lower than Freedom.   This is confusing because
another contirbutor stated the opposite.  At lower altitude greater
reboost fuel mass is needed by LLNL than Freedom, per kilo of station
weight.   You seem to justify this by saying it is small compared to
the overall weight saving of the LLNL design. It is really difficult
for me to comment on that without numbers.
-
I do not agree with having a big LLNL volume, most of which is not
available for microgravity.  You say put long extensions along the
zero-g axis of LLNL.   I say, do that and get rid of the spinning
part of the station, hence reduce drag and make the system even
lighter.  Your reason for a spinning station is to test human
subjects in Moon and Mars level gravity equivalents.   That makes a
presumption for that to be the primary goal of a space station, which
many people would seriously question.......
-
I like Wales Larrison's treatise which explains why a single Soyuz is
too small to be an ACRV.   A spinning station is limited to one
zero-g docking port at each end, and this is not adequate for docking
the large number of Soyuzes which would be required.  A non-spinning
station could have a row of docking ports along it side.  A spinning
station would need a new design of large manned ferry craft to act as
ACRV and resupply.   Similar to the design in the latest Aerospace
America.  - Also, the LLNL station subject to high drag is even more
vulnerable to decay in the event of propellant resupply problems.
+

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

End of SPACE Digest V12 #629
*******************