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Subject: SPACE Digest V13 #205

SPACE Digest                                     Volume 13 : Issue 205

Today's Topics:
   Re: NASA A socialist bureaucracy (was : ONE SMALL STEP - REPLY)
             Celestron Telescopes
          Re: Government vs. Commercial R&D
                 Re: dynasoar
              Galileo Update - 02/25/91
             Re: Terraforming, sun shield
     Re: Commercially-funded Space Probes (was Re: Space Profits)
            re:m mystery? -dilemma
     Re: Commercially-funded Space Probes (was Re: Space Profits)

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
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----------------------------------------------------------------------

Date: 26 Feb 91 03:26:51 GMT
From: celit![e-mail]  (Dave Smith)
Subject: Re: NASA A socialist bureaucracy (was : ONE SMALL STEP - REPLY)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
 >In article <[e-mail]> [e-mail] (Srinivas Bettadpur) writes:
 >>I wonder if a commercial company
 >>would take the risk of going into something as large in scope as the
 >>GPS system, which certainly has commercial applications...
 >
 >The problem with GPS is, how do you make money on it?  Commercial
 >availability of GPS -- which is inherently difficult to charge for, since
 >receivers are entirely passive -- has largely destroyed the commercial
 >navsat market.  Schemes like Geostar, in which your position is determined
 >by interaction with the satellites and they can refuse service if you haven't
 >paid your bill, are much more commercial but are having real trouble
 >getting started.

Does anyone know if Iridium has a location mode built into the phones?  That
would be pretty handy.  In fact, it could even be set up as a 976 number :-)


--
David L. Smith
FPS Computing, San Diego        ucsd!celit!dave or [e-mail]
"It was time to stop playing games.  It was time to put on funny hats and
eat ice cream.  Froggie played his oboe" - Richard Scarry

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

Date: 25 Feb 91 15:30:33 GMT
From: wuarchive!zaphod.mps.ohio-state.edu!caen!news.cs.indiana.edu!maytag![e-mail]  (Alex Lopez-Ortiz)
Subject: Celestron Telescopes



Are celestron telescopes any good?
Are these the rigth newsgroups to ask?

Thanks guys

Alex
University of Waterloo

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

Date: 25 Feb 91 15:54:55 GMT
From: skipper![e-mail]  (Mary Shafer)
Subject: Re: Government vs. Commercial R&D

In article <[e-mail]> [e-mail] (Nick Szabo) writes:

   Another source
   of resistance will be geographical sites that have been picked for
   political reasons, and don't necessarily correspond to good university
   or corporate centers.  Fortuneately, we have a different set of people
   from different states in power right now.  If we can match them to
   good universities, perhaps we can get somewhere with this.

Well, some of the geographical sites were picked for operational
reasons.  Dryden for its lakebeds and restricted areas, Kennedy and
Wallops for downrange safety, Ames for being on the opposite coast
from Langley (WW II).

Even the sites that were picked for political reasons probably can't
be moved.  Lewis's engine test cells, Langley's tunnels, etc. can't
just be packed up and moved.  Nobody that's in power now will want to
bite the bullet and pay for all these things.  Do you have any idea
what a hypersonic tunnel costs?

--
Mary Shafer  [e-mail]  ames!skipper.dfrf.nasa.gov!shafer
           NASA Ames Dryden Flight Research Facility, Edwards, CA
                     Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot

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

Date: 24 Feb 91 20:53:44 GMT
From: wuarchive!cs.utexas.edu!ut-emx!nowhere![e-mail]  (Steven King)
Subject: Re: dynasoar

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Mike Bishop) writes:
>> Can anyone tell me what ever became of the Dynasoar project?
>Dyna-Soar per se was killed, although low-level work on vaguely similar
>things has continued.  Its problem was the lack of a mission, since the
>wingless spacecraft had already proved capable of doing almost everything
>Dyna-Soar could have done.

   I'm afraid I'm going to disagree with Henry on this. DynaSoar had a
 mission; its the same mission that the Air Force currently uses aircraft
 for in the atmosphere. It had a limited payload capacity - you wouldnt
 have wanted to try building a space station with it, but it could take
 a pilot and 500? kg to LEO. Its advantage over its wingless contemporaries
 was that it wouldnt require anything near the recovery effort they did
 ( Naval assets that in an crisis might well be needed elsewhere ) as it
 could return to any friendly airfield. It would have been usefull anytime
 we needed to get a man tended payload into orbit fast, orbit a few times
 and then recover the package with a minimum effort. At that time there
 wasnt any treaties restricting the deployment of nuclear weapons in
 space, the Soviets were suspected of testing fractional orbital
 bombardment systems, and a military rivalry in space could have easily
 been the the outgrowth of the political rivalry.

>> Was this an Air Force endevor?
>Yes.

  This was a military project ( Air Force ) for military objectives
 ( principly reconnaissance ). It was terminated due to the decision to
 demilitarize America's space efforts.

>> It seems this was some sort of forerunner of the Shuttle.
>Only in a very loose way.  Dyna-Soar would have gone up on top of a Titan;
>it had no substantial propulsion system of its own.

   The DynaSoar was a lifting body design and was to use H2-O2 for its RCS.
 Not alot of fuel, but enough to change its orbit once the Titan got it
 there.

   One of the neat things about DynaSoar was that is used radiative and
 perspiration cooling for re-entry. The skin was of a metal chosen for its
 high emissivity and thermal charateristics ( with columbium for the nose
 and leading edges ). But it also had a "water-gel" blanket beneath that
 provided additional cooling. This was felt like material which was soaked
 with water and some sort of emulsifier to keep it from ending up at the
 tail of the vehicle after launch with an outer gasket layer and pressure
 release vents. As the heat radiated inward increased, the water would
 vaporize, build up pressure and vent. This system contributed only about
 80kg to the launch weight but gave substancial cooling. The blankets were
 designed so that they could be easily changed out on recovery and the
 vehicle quickly serviced.

   Much of the vehicle was quite simple, even primitive by todays standards.
 There was a statement in one document to the effect that the cockpit
 enviromental control system would work better if the pilot kept his
 helmet visor closed.
   It was because of this simplicity that I was interested in the design. It
 seemed like a likely candidate to derive a private re-entry vehicle from.
 However, despite the project having been cancelled some 20 years earlier,
 most of the documents listed in the STAR were still classified.
   Its interesting that in some of the SDI literature, one sees a line
 drawing of a DynaSoar like vehicle atop a Titan like rocket...




--
Look Ma! No .sig!
                                        ..!cs.utexas.edu!ut-emx!nowhere!sking

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

Date: 25 Feb 91 19:43:48 GMT
From: usc!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 02/25/91


                           GALILEO STATUS REPORT
                            February 25, 1991

     The health of the Galileo spacecraft continues to be excellent.  Today's
activities will consist of:

        o Performing a sun acquisition.
        o Turning on the star scanner high voltage.
        o Transitioning from all-spin to dual-spin operation.
        o Performing a cruise science memory readout for the EUV
          (Extreme Ultraviolet Spectrometer), MAG (Magnetometer),
          and DDS (Dust Detector) instruments.
        o Resetting the Command Loss Timer to 240 hours.

     Tomorrow, no spacecraft activity is planned.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [e-mail]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | Is it mind over matter,
  ___| | | | |__) |/  | | |___   M/S 301-355        | or matter over mind?
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | Never mind.
 |_____|/  |_|/       |_____|/                      | It doesn't matter.

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

Date: 25 Feb 91 20:22:34 GMT
From: snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!bonnie.concordia.ca!news-server.csri.toronto.edu!helios.physics.utoronto.ca!aurora.physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: Re: Terraforming, sun shield

In article <[e-mail]> [e-mail] (Clayton Cramer) writes:
>In article <[e-mail]>, [e-mail] writes:
>>
>> Problem:  Terraform Venus.  Method:  Orbit a large shield in front of the sun
>> to cut incident visible sunlight by 50%.  Assume:  Manufacturing and
>
>If you put it in orbit around Venus, it will, as they say, orbit
>Venus -- so you don't have much of a shield several hours of the
>day.  If it is in orbit around the Sun, the problem becomes more
>severe, since you won't have a shield for most of the year.  (The
>closer you are to the Sun, the faster it must revolve in order to
>stay in orbit).
>
   Nope. There's a point, the Sun-Venus L1 point, where an object much
less massive than Venus will orbit the Sun with the same period as Venus
itself, and lie between the Sun and Venus at all times. Because the
radiation pressure on this disk would be considerable, the disk would have
to lie somewhat sunward of the Sun-Venus L1 point.  Mathematically, a solar
sail oriented at normal incidence to the Sun orbits as if the Sun itself
were less massive, so it can have the same period as a planet further out
from the Sun, even ignoring that planet's gravitational influence in
forming a Lagrange point.


--
 Christopher Neufeld....Just a graduate student  | Note: new host.
 [e-mail]    Ad astra! | helios will still
 cneufeld@{pnet91,pro-cco}.cts.com               | forward my mail to
 "Don't edit reality for the sake of simplicity" | me on aurora.

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

Date: 25 Feb 91 20:51:57 GMT
From: idacrd![e-mail]  (Robert McGwier)
Subject: Re: Commercially-funded Space Probes (was Re: Space Profits)

From article <[e-mail]>, by [e-mail] (Henry Spencer):
> In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>>Not at this time.  Some effort is needed to bring deep space
>>exploration down to the $10-50 million/probe range that universities,
>>corporations, and other non-government organizations might consider.
>>The major R&D items needed:
>>
>>* Microsatellite technology:
>>    -- standard microdevice bus
>>    -- small instruments
>>* Upper stage for microsatellites
>>* Pre/post calibration (target switching) and bandwidth upgrades to DSN
>>  to allow coverage of a much larger sky population
>



A Microsat bus is available from Interferometrics, Inc. in Vienna, Va.
for about $1000000  (10^6) WITHOUT the instrument.  Ariane will launch this
package for about half a million on launches where an ASAP is available into
either polar or geo-transfer orbit.  The volume available for experiment
in Microsat technology available from I^2 is VARIABLE since the unique
modular construction allows them to be stacked several deep.

Bob McGwier


--
____________________________________________________________________________
    My opinions are my own no matter    |    Robert W. McGwier, N4HY
    who I work for! ;-)            |    CCR, AMSAT, etc.
----------------------------------------------------------------------------

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

ReSent-Message-ID: <Added.kbmGIMe00UkTE=[e-mail]>
Resent-Date:  Mon, 25 Feb 91 09:52:50 EST
Resent-From: Harold Pritchett <[e-mail]>
Resent-To: Space discussion group <[e-mail]>
Date:     Sat, 23 Feb 91 02:28 CDT
From: <[e-mail]>
Subject:  re:m mystery? -dilemma
Original_To:  BITNET%"space@finhutc"

:    As a space activist, however, I think these types of hype jobs raise
: an interesting dilemma.
...
: The fact is that such
: things capture the publics attention and if we can answer meaningful
: questions by visiting such areas then why not use it to build public
: interest.
...
: Further, the power

I would hope that our integrity and credibility as scientists is more
important than some cheap public relations.

--Scott Cromar
[e-mail]

------------------------------
REPLY:
  Please do not misinterpret the question. I am not advocating
the abandoment of morals, ethics, integrity or credibility. In fact
I am advocating that we publically demonstrate these virtues. I have
two reasons for posing such issues. First, I am and educator and spend
much of my time teaching scientific methods/reasoning courses to
undergraduates. My interest in things like the Mars face is as a
class example of how evidence as "solid" as a photograph does not
provide "proof" of anything. Through the past several years I have
(as well as colleages) have been distressed my the increasing
proportion of time that has to be spent teaching such fundamental
reasoning skills to Sph, Jr. & Sr. university students. In fact,
where I once spent perhaps one or two class periods /semester
discussing such simplistic cases, I often spend 4 or 5 classes.
Even then, I often have to address several students after hours
on the reasoning that discredits the "obvious" interpretation.
My second reason for being interested in the issue is because
I am a space enthusiast who would like to see space exploration
at the top of the national agenda again. I honestly believe that
space exploration holds the potential for lessening many of our
national and international woes (much as manifest destiny in the
1800's led to economic and cultural advances). My thinking is
that we might identify a phenomenon, such as the mars face, which
is located in an area that is important for several reasons.
We allow the "phenomenon" to gain some public interest (which they
seemed to do whether we want them to or not). In fact, the hype
jobs about faces, alphabets, and photos of Heaven, are what
make the news, and talkshows, while the really important findings
remain out of public view. So let one catch the imagination of the
public and then show how scientists can reason to what is
a more probable explanation. -Kind of a national science demonstration.
A comparison between what tabloids/intuitions/biases tell you and
what empiricism/rationality predicts. Have the scientists give their
reasoning and make their predictions and then test those predictions
by actually going and investigating the site as part of a "more"
serious investigation of the region. In short, for the past
15 years the hype and hoopla have gotten all the publicity and
we have seen performance declines in academics and the work force.
I see nothing wrong with making the public aware of the things that
can be known and the improved decision making processes that can
be gained by becoming proficient in rational thinking processes.
Please don't misread my hypothetical scenario as an excuse to comprise
one's scientific integrity. I am suggesting a way to showcase
scientific reasoning and integrity in hopes of attracting more
more people to the various scientific/technological
disciplines (Much as the Moon race did in the '60s). My second
hope is that finding such an issue might put space exploration
back at the forefront of the national agenda, thereby providing
a future for the continued expansion of human knowledge and
growth for the world economy.

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

Date: 25 Feb 91 17:38:23 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Commercially-funded Space Probes (was Re: Space Profits)

In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>Not at this time.  Some effort is needed to bring deep space
>exploration down to the $10-50 million/probe range that universities,
>corporations, and other non-government organizations might consider.
>The major R&D items needed:
>
>* Microsatellite technology:
>    -- standard microdevice bus
>    -- small instruments
>* Upper stage for microsatellites
>* Pre/post calibration (target switching) and bandwidth upgrades to DSN
>  to allow coverage of a much larger sky population

Also useful would be major reductions in launch costs, else you spend all
that $10-50M on the launch and have nothing left over for spacecraft and
operations.
--
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  [e-mail]  utzoo!henry

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

End of SPACE Digest V13 #205
*******************