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Subject: SPACE Digest V11 #310

SPACE Digest                                     Volume 11 : Issue 310

Today's Topics:
           Payload Status for 04/23/90 (Forwarded)
           Payload Summary for 04/22/90 (Forwarded)
              Re: Dyson spheres?
              Re: Dyson spheres?
                Pegsat Update
          Re: Radar (was Re: Drake Equation
         NASA Headline News for 04/23/90 (Forwarded)
                Re: Our galaxy
              Re: Dyson spheres?
Dirigible launchers (was Re: Pegasus launchers, space-going DUCT TAPE)
----------------------------------------------------------------------

Date: 23 Apr 90 21:18:30 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Payload Status for 04/23/90 (Forwarded)


  Daily Status/KSC Payload Management and Operations 04-23-90.


  - STS-31R HST (at pad-B) -

  HST battery installation was completed Friday and launch
  closeouts were completed Saturday.  Launch countdown support
  continues today.


  - STS-35 ASTRO-1 (at OPF) -

  Support for orbiter rollout to pad-a was provided Saturday and
  Sunday.  BBXRT liquid argon servicing will occur today.


  - STS-40 SLS-1 (at 0&C) -

  Preps for experiment train interface test were worked Friday and
  Saturday and will be completed this morning.  The actual
  interface will start today.


  - STS-42 IML-1 (at O&C) -

  Module pyrell foam replacement, floor staging, and rack staging
  were worked Friday and Saturday and will continue today.


  - STS-45 (Atlas-1)-

  Bonding straps were installed Friday and keel support structures
  were installed Saturday.  Cold plates will be installed today.


  - STS-55 SL-D2 (at O&C) -

  Rack 12 staging will continue today.


  - HST M&R (at O&C) -

  ORUC interface testing continues.

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

Date: 23 Apr 90 21:15:45 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Payload Summary for 04/22/90 (Forwarded)


                            STS-35 PAYLOAD STATUS REPORT
                         SUNDAY, APRIL 22, 1990 --   2 P.M.


          Patricia E. Phillips
          NASA Public Affairs/KSC
          407/867-2468


          ASTRO-1/STS-35


               Space Shuttle Columbia, with Astro-1 in the payload bay, was
          rolled out to Launch Pad 39A this morning.  The Broad Band  X-Ray
          Telescope (BBXRT) will be serviced with liquid argon as a coolant
          on    Monday,  April  23.  The  approximate two-hour operation is
          scheuled to begin at about 8 a.m.  This  servicing  places  BBXRT
          well  within the timeline of needing coolant replenishment by the
          morning of April 27.

               Three other servicing operations are scheduled for BBXRT  at
          Launch Pad 39A.  Liquid argon, which provides 12 days of cooling,
          will be used in operations planned for April 28 and  May  8.  The
          final servicing,  which will provide 16 days of cooling,  will be
          completed overnight May 12-13 using solidified argon.

               Since each servicing will require that the payload bay doors
          be opened briefly, the payload pallet will be cleaned again about
          four days before  launch.  A  contamination  inspection  is  also
          scheduled shortly  before flight.

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

Date: 23 Apr 90 07:47:52 GMT
From: zaphod.mps.ohio-state.edu!usc!oberon.usc.edu![e-mail]  (Steve Robiner)
Subject: Re: Dyson spheres?

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] (Andrew Salamon) writes:

>    the advancement  of some civilizations,  they  would  develop  the
>    ability to  transform all of the matter of their solar system into
>    a very thin  layered  hollow sphere  centered  on  their star.  In
>    this way  they could fully utilize the total stellar energy output
>    as well as the maximum surface area on the interior of the sphere.

A civilazation that advanced would surely not need a star as an energy source.
In order to move that much mass around you would have to have a very advanced
energy source already.  And since such a sphere would have no 'gravity' or
other centripital forces at its poles, and no 'night' anywhere on the surface,
the simple creation of another planet would be far more preferable.

>    Dyson  recognized that an Earth-based observer would  see  a  very
>    bright infared source with no visible component.
>
If they were that advanced, they'd surely contruct the sphere out of materials
which fully absorbed all the energy from the star in *every* wavelength.  We
would never see it even if they did exist.

=steve=

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

Date: 23 Apr 90 16:14:58 GMT
From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!ria!uwovax![e-mail]  (Terry Gaetz (Astronomy, U. Western Ontario))
Subject: Re: Dyson spheres?

In article <[e-mail]>, [e-mail] (Steve Robiner) writes:
[...]
> If they were that advanced, they'd surely contruct the sphere out of materials
> which fully absorbed all the energy from the star in *every* wavelength.  We
> would never see it even if they did exist.

If all the energy is absorbed, the material will heat up and emit thermal
radiation; equilibrium is reached when the thermal energy emitted equals
the energy absorbed.  The second law of thermodynamics can be used to show
that a perfect absorber must also be a perfect emitter; consider the
definition of a thermal "blackbody" source.  Furthermore, Hawking showed
that even _black_holes_ emit thermal blackbody radiation.
--
Terry Gaetz         --   [e-mail]   --   [e-mail]

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

Date: 23 Apr 90 20:42:34 GMT
From: sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Pegsat Update


                     TUESDAY, APRIL 17, 1990

PEGSAT UPDATE:  Pegsat project officials at the Churchill Research
Range in Canada have reported the successful discharge of one of
the two barium canisters over Great Slave Lake, Northwest
Territories.  A chemical cloud followed the discharge at 1:45 a.m.
EDT Monday.  The cloud was visible as far west as Vancouver,
British Columbia.

                     FRIDAY, APRIL 20, 1990

PEGSAT UPDATE:  Project officials on Goddard's Pegsat project were
thwarted for the second time Wednesday night in igniting a barium
discharge from the Pegsat satellite.  Reason:  bad weather over
Central Canada.  Dr. Robert A. Hoffman, Project Scientist, said the
next opportunity for the project to make a barium discharge would
come Friday at 24 minutes after midnight EDT.  The project,
following a successful launch of the satellite on April 5 from
under the wing of a NASA B-52 off the coast of California,
successfully fired one of the two barium canisters earlier in the
week.  The barium cloud created by the discharge was sighted by
persons on the ground in Western Canada and in the Northwest United
States and by optical sighting locations in both the United States
and Canada.  The experiments are designed to make studies of the
Earth's magnetic and electrical fields.

 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

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

Date: 24 Apr 90 03:46:10 GMT
From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Radar (was Re: Drake Equation

[e-mail] (John Sahr) writes:
>Radio amateurs familiar with "meteor scatter" accompish hard target
>scatter at hundreds of kilometer ranges with a few hundred watts of
>transmitter power.

Unless they're doing something very different from the meteor-bounce
communications systems in use for other purposes -- no, meteor-bounce
is not all amateur these days -- they are getting bounces off the
ionized trails, not the objects themselves.
--
If OSI is the answer, what on |     Henry Spencer at U of Toronto Zoology
Earth could be the question?? | uunet!attcan!utzoo!henry [e-mail]

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

Date: 23 Apr 90 21:13:57 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 04/23/90 (Forwarded)

-----------------------------------------------------------------
Monday, April 23, 1990                Audio Service: 202/755-1788
-----------------------------------------------------------------

This is NASA Headline News for Monday, April 23.....


The countdown for tomorrow's launch of the Space Shuttle
Discovery with the Hubble Space Telescope aboard continues with
no problems.  The launch window opens at 8:31 a.m., EDT,
tomorrow.  The weather forecast for the Cape tomorrow is quite
favorable...a 70 percent chance of meeting launch criteria.

The count will be in a daylong hold until resumption at 6:11 p.m.

Bill Taylor, telescope systems manager, reported earlier today
all telescope systems are functioning properly, batteries are
fully charged and everything is ready to go for tomorrow
morning.  Taylor added the batteries are good for four to five
launch attempts before recharging would be needed.


While the launch of STS-31 neared, the STS-35 mission launch drew
closer.  Columbia, carrying the Astro payload, was rolled out to
launch pad #39A, Sunday.  The last time two shuttles were on
launch pads at the same time was in January 1986.  Columbia was
on pad 39A...Challenger was on pad #39B. The Columbia launch is
scheduled for mid-May.

                        *              *

The first Tracking and Data Relay Satellite, TDRS-1, will be
reactivated to supplement K-band communications on TDRS West.
The activation is necessary because of the loss of an antenna on
TDRS-3.  K-band communications requests have a tendency to back
up particularly during space shuttle operations.  TDRS-1 will be
on station for the support role by May 1.

                        *              *

Aviation Week reports the Aerospace Safety Advisory Panel says
unless space shuttle propulsion and other systems are redesigned
NASA faces the possibility of another space shuttle accident.
The panel's report has been disputed by NASA Administrator Truly
who says the comments about the liklihood of another space
shuttle accident are unfounded.

                        ***************









-----------------------------------------------------------------
Here's the broadcast schedule for Public Affairs events on NASA
Select TV.  All times are EDT.

Tuesday, April 24.....

        4:00 a.m.     Coverage begins of the STS-31 mission
                      with pre-launch activities at KSC.
                      The launch window opens at 8:31 a.m.

       10:00 a.m.     Post launch briefing from KSC.

       12:00 noon     Change of Shift briefing from JSC

        2:00 p.m.     Telescope change of shift briefing
                      from GSFC.

        2:35 p.m.     Tape replay of HST inspection.

        6:00 p.m.     Tape replay of Flight Day 1 activities.

All events and times are subject to change without notice.

NASA Select TV may be monitored on Satcom F2R, Transponder 13.
Each day at 6:00 p.m.,EDT, Satcom F1R, Transponder #13, located
over the Pacific Ocean will carry daily NASA Select TV
highlights.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
EDT.  Updates as needed during STS missions.
-----------------------------------------------------------------
A service of the Internal Communications Branch, NASA HQ.

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

Date: 24 Apr 90 02:46:05 GMT
From: cs.utexas.edu!news-server.csri.toronto.edu!qucdn![e-mail]  (Arnold G. Gill)
Subject: Re: Our galaxy

In article <[e-mail]>,
[e-mail] (Will Martin) says:
>
>The radio program "Stardate" that was aired on Sunday, April 22, described
>our galaxy as a spiral like Andromeda. I had thought I had heard some
>recent news items reporting that new discoveries or interpretations have
>provided evidence that our galaxy is instead a barred spiral.
     The lastest does seem to indicate that our Galaxy is indeed a barred
spiral.

>In a related topic, is there any "better" name for our galaxy than "the
>Milky Way"? Something that sounds more like a proper name and is more
>dignified? I would think there is some astronomic term, perhaps a
     The proper astronomical term is simply "the Galaxy", with a capital 'G'.
-------
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
|  Arnold Gill                        |                                     |
|  Queen's University at Kingston     |     If I hadn't wanted it heard,    |
|  BITNET   : gilla@qucdn             |       I wouldn't have said it.      |
|  X-400    : [e-mail]  |                                     |
|  INTERNET : [e-mail]  |                                     |
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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

Date: 23 Apr 90 14:22:49 GMT
From: sdd.hp.com!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew![e-mail]  (Brian or James)
Subject: Re: Dyson spheres?


 One way of simulating a solid surface around a star [and therefore avoid
the traffic control headaches involved in making sure that none of <insert
very large number here> energy absorbing units' orbits intersect] would be
to suspend habitats from solar sails, and have them just balance their
star's gravity with reflected light. Problem with that is that the 'sun'
light has to be reflected back at the star providing it, and that'll make
the star burn hotter for a shorter time. I'm sure this is a minor problem,
solvable by suspending the sails further out, so when temperatures rise,
the builders don't get cooked. Mind you, *I* wouldn't want to live there.
I have a real problem trusting my life to something with the word 'shroud'
in it.
                                JDN

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

Date: 23 Apr 90 06:56:26 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Dirigible launchers (was Re: Pegasus launchers, space-going DUCT TAPE)

In article <[e-mail]> [e-mail] ("HENRY S. COBB, 1LT.") writes:
>The "launch-a-rocket-from-a-dirigible" idea was tried as far back as the
>late '50's.  Look it up under the name "rockoon" (from rocket-baloon).
>In the rockoon concept, the baloon was expendable, but high-altitude
>baloons aren't all that expensive (under $1 million per shot, if memory
>serves).

I remember the "rockoon" well -- it was a way to try and do some of what
the Scout does now, with fewer stages.  The rocket hung from a high altitude
baloon, about 30 degrees from the vertical -- and launched right where it
sat, destroying the baloon as it went.

But "dirigible" is something else -- a powered, guided LTA platform.  There's
no need for the Pegasus to damage it -- any more than they needed to sacrifice
the B-52.  You drop the rocket and let it ignite a good distance away.

The biggest disadvantage to the dirigible is its lack of speed.  It has too
much drag to fly as fast as a B-52.  But its potential endurance and ceiling
are incredible.  You could essentially fly a complete launch pad and staff,
with all kinds of leisure to verify that everything's OK before launching.

Realities being what they are, I don't expect OSC to try it.  But someone will!

--
"How can a man of integrity get along    ///  Tom Neff
in Washington?" -- Richard Feynman      ///   [e-mail]

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

End of SPACE Digest V11 #310
*******************