Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_0/V13_044.TXT

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Subject: SPACE Digest V13 #044

SPACE Digest                                      Volume 13 : Issue 44

Today's Topics:
        CANCELLED LITHIUM/BARIUM EXPLOSION !!!
         Re: LOX/LH2 in Shuttle Payload Bay (2 of 2)
        Re: LOX/LH2 in the Shuttle Payload Bay
              Re: US buys Soviet reactor
               Re: Interstellar Travel
    Re: What are the qualifications needed for astronauts
             Pioneer 10 Update - 01/11/91
           Re: Humankind's Second Off-world Colony
           Re: Humankind's Second Off-world Colony
           Understanding Solar Terrestrial Reports
        Re: LOX/LH2 in the Shuttle Payload Bay
            Re: Satellite photo of eclipse

Administrivia:

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

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

Date: 11 Jan 91 14:14:31 GMT
From: usc!samsung!spool2.mu.edu!news.cs.indiana.edu!nstn.ns.ca!cs.dal.ca!dal1![e-mail]
Subject: CANCELLED LITHIUM/BARIUM EXPLOSION !!!

Hi folks!

    Just wondering in lieu of the cancelled lithium/barium explosion from
Thursday Jan. 10th, does anybody know if they will take place on Saturday
night. If so what time? I will be grateful for any replies!

                            Davis Bennett
                            Dalhousie U.
                            Halifax, N.S.,
                            Canada

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

Date: 11 Jan 91 04:58:14 GMT
From: usc!elroy.jpl.nasa.gov!zardoz.cpd.com!dhw68k!ofa123![e-mail]  (Wales Larrison)
Subject: Re: LOX/LH2 in Shuttle Payload Bay (2 of 2)

Allan Sherzer writes:
> Why not mount the Centaur upside down? That would put much less
>stress on the tanks since they would be riding on the 10K lb
>payload rather than the other way around. A harness could be built
>for the payload so it wouldn't rattle around if the fuel needed to
>be dumped. Of course, a way would need to be found to dump the fuel
>still.
   Good question.  Turns out, the technical reason is to place
Center of Gravity of the payload-upperstage over the C.G. of the
shuttle to ensure the system is controllable in descent.  If you
turn the Centaur/payload combination around, the C.Gs don't match.
Also, it's easier to toss it out over the cabin, than toss it out
over the tall tail.

 Allen Sherzer writes:
>True but the point remains. ALL payloads are covered under the NASA
>Authorization Act of 1991 AND the administrations space policy from
>the mid 80's. The only exception is for payloads which require a
>human presence. I don't think Galileo qualifies.
   Hmmm... I think the wording is "which require unique shuttle
capabilities".  Which means manned missions, missions requiring
orbital repair or assembly, or missions to return a payload to the
Earth.  As things stand now, Galileo doesn't qualify.  In the mid-
1980's when the decision was made, since the Titan-IV would not have
been available, Galileo would have qualified (no other launch
vehicle could have been made ready).

Nick Szabo write:
>There is no reason interplanetary probes should be treated any
>differently than industrial satellites.  The law covering
>industrial satellites should be extended to planetary probes and
>most DoD satellites, IMHO.
  And from the wording of the law, it has been.

Christopher Neufeld writes:
>Seriously, though, the pictures of objects leaving the cargo bay
>always show the rocket nozzle of the Centaur or IUS pointing at the
>floor of the payload bay, which would make the rocket horizontal in
>the launch stack configuration. Is there a gimbal which swings the
>whole thing to vertical, or is the payload actually mounted that
>way? If the latter, it would be impractical to put the engine on
>top of the payload.....
   There's a gimbal, and a small motor to rotate the payload about
60 degrees (?? less than 90 degrees for sure) out of the bay before
release.  The actual separation is done by springs.  You could mount
the payload facing back, and just yaw the orbiter 180 degrees before
separation so the payload departs into the same orbit as if it was
mounted forwards.  It would have a couple of complications though -
you'd have to clear that high tail - and lifting the front side up
allows the astronauts to visually verify the rotation is complete
out the windows of the crew compartment.

   Will there by LO2/LH2 payloads on the shuttle in the future?
Probably not upperstages - although I can conceive of a LO2/LH2
powered small manned orbital transfer vehicle that is launched and
recovered during a single shuttle mission used for satellite
inspection and repair at high altitude and inclination.
-----------------------------------------------------------------
Wales Larrison                          Space Technology Investor



--
Wales Larrison
Internet: [e-mail]
Compuserve: >internet:[e-mail]
--------------------------------------------------------------------------

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

Date: 11 Jan 91 22:27:35 GMT
From: hub.ucsb.edu!ucsbuxa![e-mail]  (Charles Frank Radley)
Subject: Re: LOX/LH2 in the Shuttle Payload Bay



I believe the discrepany could be explained as follows:-
I do not think  the Shuttle was to carry Centaur-D but rather
a larger Centaur-G or G-Prime.......?

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

Date: 11 Jan 91 21:03:13 GMT
From: usc!zaphod.mps.ohio-state.edu!rpi!bu.edu!snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!bonnie.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: US buys Soviet reactor

In article <[e-mail]> [e-mail] (Stewart T. Fleming) writes:
>It would appear that there is (strong ?) political opposition to the use
> of nuclear reactors in space, at least on the US side.  Has this
> restricted funding/development ?

Not significantly, I don't think.  What has restricted funding and
development has been more the lack of a firm requirement for nuclear
power in the US space program.  What little work is being done now is
mostly inspired by SDI.

> ... is the purchase of the reactor not just a way of catching up with the
> technology, rather than the start of any plan to deploy such reactors ...

I'd be extremely surprised if there was any intent to launch the Soviet
reactor.  Sounds like they mostly want to tear it apart to find out how it
works and what it's made of.

>Is the power output of the Soviet reactor considerably greater than any US one ?

There are no US space reactors.

>As I understand it, most US satellites are solar-powered - what is the
> typical power output of a solar panel configuration ?

Depends on how big the panels are.  Getting tens of kilowatts is not hard
with current technology.

The Soviets used reactors for their radarsats not because they could provide
more power, but because the radarsats wanted to operate at very low orbital
altitudes, where the air drag of a big solar array would have been a very
serious problem.
--
If the Space Shuttle was the answer,   | Henry Spencer at U of Toronto Zoology
what was the question?                 |  [e-mail]   utzoo!henry

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

Date: 11 Jan 91 21:10:25 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Interstellar Travel

In article <[e-mail]> [e-mail] (Tom Fitzgerald) writes:
>> (For starflight in particular, it is a mistake to try to
>> hurry too much, because probes launched later are quite likely to get
>> there sooner due to improved technology.)
>
>I would think that the improved technology would result from all the things
>you learned building and launching the earlier probes...

There is some truth in this, but that effect is more along the lines of
debugging and optimizing existing technology.  For starflight, what we
really need is breakthroughs, which are not likely to come from an
operational program.

With near-future technology, starflight even to the nearer stars will
have travel times approaching a century.  That is a very long time in
the history of technology, long enough for multiple breakthroughs.
Very modest assumptions about the growth rate of attainable starflight
speeds say that a starprobe launched in (say) 2050 will get there sooner
than one launched in 2010.
--
If the Space Shuttle was the answer,   | Henry Spencer at U of Toronto Zoology
what was the question?                 |  [e-mail]   utzoo!henry

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

Date: 11 Jan 91 15:05:21 GMT
From: usc!samsung!caen!maize.engin.umich.edu![e-mail]  (Ken Sheppardson)
Subject: Re: What are the qualifications needed for astronauts

[e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Matt Harrington) writes:
>>I know that to be a fighter pilot, one must meet rigorous
>>physical and mental requirements.  Does anyone know the
>>requirements for astronauts?  For example, do they need to
>>have perfect vision?  Do they need to be fighter pilots
>>first?  From where are the people chosen, an academy?
>
>Here's the latest iteration of my standard response to this:
>
>Q. How do I become an astronaut?
>
>A. ...

   In addition to Henry's comments, I'd suggest that you start to send
   applications in as soon as possible, even if you don't consider yourself
   to be qualified at this point in your career. You want to do whatever
   you can to show the selection folks that your interested, to make
   yourself a familiar face, and to stand out from the crowd.

   Dislaimer: I am not, nor have I ever been, associated with the astronaut
              program in any way. I only know what's worked/seems to be
              working for others.




--
===============================================================================
 Ken Sheppardson                                  Email: [e-mail]
 Space Station Freedom Advanced Programs Office   Phone: [phone]
 NASA Langley Research Center, Hampton VA         FAX:   [phone]
===============================================================================

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

Date: 11 Jan 91 23:06:58 GMT
From: sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Pioneer 10 Update - 01/11/91


                    PIONEER 10 STATUS REPORT
                       January 11, 1991

     On January 6, following an IPP procedure where the instruments were
powered off, the 34 meter Goldstone station experienced antenna problems.
As a result, commands to turn on the CRT and GTT instruments on the Pioneer
10 spacecraft could not be sent until the next day.  On January 7, a power
failure at the 70 meter Goldstone station caused a 1 hour loss of telemetry
data.  On January 8, CPA (Command Processor Assembly) problems at the 70
meter Spain station prevented the transmission of critical roll phase, stored
command logic, and PA instrument commands.  The commands were sent 15 hours
later, during the next scheduled support.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 11 Jan 91 18:32:24 GMT
From: ncar.ucar.EDU![e-mail]  (Gary Strand)
Subject: Re: Humankind's Second Off-world Colony

> Nick Janow

> Another problem of building on ice might be creep (slow movement into the
> ice).  Does anyone know if this is a problem in Antarctica?

  I recall reading about some kind of drilling being done in Antarctica in
  which the drilling had to be stopped, and by the time the equipment was
  ready to go again (some period of a few hours, I think) the movement of
  the ice had trapped the drill in the hole rock-solid. It took several
  months to free the drill.

  So, yes, even slow ice movement can catch up on you, so to speak.
--
Gary Strand                           There is only one success -- to be able
Internet: [e-mail]      to spend your life in your own way.
Voicenet: [phone]                                 - Christopher Morley

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

Date: 10 Jan 91 13:44:30 GMT
From: van-bc!rsoft!mindlink![e-mail]  (Nick Janow)
Subject: Re: Humankind's Second Off-world Colony


Another problem of building on ice might be creep (slow movement into the ice).
Does anyone know if this is a problem in Antarctica?

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

From: cmi![e-mail]
To: dartvax![e-mail]
Subject: Understanding Solar Terrestrial Reports
Date: Fri Jan 11 17:45:51 1991

I seem to have gotten the first part of Understanding Solar Reports
but have not seen the remaining parts. Have they come out? Have I
missed them somehow? Where does one get the rest of this document?
Thanx...

Quote for the day:
                "                            "
                                Millie Vanilli
*-----------------------------------------------------------------------*
| INTERNET:   cmi![e-mail]                    |
|             cmi![e-mail]                |
|             [e-mail]             (for intelligent mailers)    |
| UUCP:       ... {harvard,rutgers,decvax,uunet}!dartvax!cmi!jerry      |
*-----------------------------------------------------------------------*

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

Date: Fri, 11 Jan 91 20:56:17 -0500
From: "Allen W. Sherzer" <[e-mail]>
Subject: Re: LOX/LH2 in the Shuttle Payload Bay
Newsgroups: sci.space
Cc:

In article <[e-mail]> Charles Radley writes:

>I believe the discrepany could be explained as follows:-
>I do not think  the Shuttle was to carry Centaur-D but rather
>a larger Centaur-G or G-Prime.......?

I received email from Glenn Seere saying the same thing. The weights
I gave where for Centaur-D which weighs much less than the Cantaur-G
which was to be used on the Shuttle.

It therefore seems that the ability to dump fuel is needed if a Centaur-G
is to be used. However, it does seem that it should be possible to use
the Centaur-D.

Glenn also pointed out that my idea of putting the payload in upside down
would put more stress on the H2 tanks than the payload would. so much
for that idea.

It would be nice if we had a LEO Gas Station like the one proposed by
LLNL. Then none of this would be a problem.

  Allen

--
+----------------------------------------------------------------------------+
|Allen W. Sherzer | America does best when it accepts a challenging mission. |
|   [e-mail]   | We invent well under pressure. Conversely, we stagnate   |
|                 | when caution prevails.   -- Buzz Aldrin                  |

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

Date: Fri, 11 Jan 91 23:51:56 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Satellite photo of eclipse


>From: John Roberts <roberts>
>Subject: Re: Umbra (eclipse shadow) satellite photo

>>From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
>>In article <[e-mail]> [e-mail] (David Cortesi) writes:
>>>There are these fine weather satellites looking down on the west
>>>coast and pacific.  Would it be possible for one of them to take
>>>pictures of the umbra, a 300 kilometer oval of shadow, as it
>>>sweeps over Baja or Mexico on that day?
>>I suspect that the answer is no.  The trouble is that the Clarke-orbit
>>metsats typically spend about half an hour doing a raster scan of the
>>Earth for each image.  They're not built for stop-motion photography,
>>even motion as slow as this.
>I recently saw a published satellite photograph of an umbra, with an
>explanation that ordinary weather satellites couldn't do it. Unfortunately,
>I can't remember the name of the satellite or where I saw the picture. :-(

Ha! Found it! The February 1991 issue of Astronomy magazine, page 22, at the
bottom of the page. As you might expect, it looks like a big shadow, dark
in the center and faint toward the outside edges. The text is as follows:

"The Moon's shadow was captured by a GOES weather satellite as the shadow
touched Earth during the July 21-22, 1990, solar eclipse. Despite the many
satellites observing Earth each day, capturing the Moon's shadow crossing
the Earth is still a relatively rare event. One reason is that the satellite
images are rarely snapshots anymore but are images created by scanning the
Earth point by point. The fast-moving shadow often disappears off the disk
before the satellite has had a chance to record the fleeting image.
- Sanjay Limaye, University of Wisconsin, Madison"
     John Roberts
     [e-mail]

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

End of SPACE Digest V13 #044
*******************