Date: Wed,  9 Dec 92 05:11:10    
From: Space Digest maintainer <digests@isu.isunet.edu>
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Subject: Space Digest V15 #525
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Space Digest                Wed,  9 Dec 92       Volume 15 : Issue 525

Today's Topics:
                        Another Orbit Question
                dialog between D. Goldin and C. Sagan
         Rush Limbaugh says problems with HST are a DoD hoax!
       Terminal Velocity of DCX? (was Re: Shuttle ...) (2 msgs)

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Date: 8 Dec 92 19:30:51 GMT
From: hdgarner@acs.harding.edu
Subject: Another Orbit Question
Newsgroups: sci.space

In article <ZOWIE.92Dec7125820@daedalus.stanford.edu>, zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes:
>In article <foo> gary@ke4zv.uucp (Gary Coffman) writes:
>   In article <1992Dec6.141449.761@ualr.edu> hdgarner@acs.harding.edu writes:
>   >In light of the fact that a geostationary orbit above only one pole is
>   >not possible, I have another question that concerns an idea that I've been
>   >working on for the past few months. Is it possible to keep a body at
>   >relatively the same point say about 20000 or so miles above the north pole
>   >or south pole of the earth? 
>
>   It would require exactly as much continous thrust as it weighs. Thus it
>   would run out of fuel quickly. Being stationary over the Earth, and at
>   only 20,000 miles, it would weigh almost the same as it weighs on the
>   surface. Things in space aren't "weightless", only things in *orbit*
>   are "weightless."
>
>A point well taken: that things in space are still subject to the Earth's
>gravity.  But, the Earth's radius is only about 30,000 / 6 = 5,000 miles.
>At an altitude of 20,000 miles above the surface, you'd only weigh about 
>1/25 of your surface weight due to the r-squared falloff in the g field.
>
>But you still can't support anything useful for any reasonable amount
>of time... :-P
>
>--zowie
>--
>DON'T DRINK SOAP! DILUTE DILUTE! OK!
I can see how a liquid fueled bidy could not remain in a stationary polar
position for very long, but what about if instead of liquid fueled thrusters
the body was equipped with ion thrusters and a solar array to power them. The
solar array would be positioned so that it faced the sun at all times. 
Any thoughts?
hdgarner@harding.edu

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

Date: 8 Dec 92 20:48:47 GMT
From: Richard Ottolini <stgprao@st.unocal.COM>
Subject: dialog between D. Goldin and C. Sagan
Newsgroups: sci.space

was sponsored by the Planetary Society at Caltech last Friday. The head of
JPL (Stone) moderated.  The format was: ten minute intro by both, followed
by 50 minutes of questions to each other and then an hour of questions
from the audience.  They were supposed to focus on topic of space exploration.
(Goldin held a NASA town meeting in LA the previous night. Any remarks?)

Goldin took the position of "an outsider".  He wanted to streamline the
NASA bureaucracy to launch more and smaller spacecraft.  He didn't care for
projects like Ulysseus to Saturn, now a four billion dollar, 20-year monster.
By the time the craft is launched, the technology is years out of date.
He challanged NASA engineers to develop rapid, light-weight, low-cost craft
employed leading-edge technology.  Rapid means 4-6 years, light-weight <1000 lbs, and low cost, a couple hundred million.  There will only be a couple large
projects like Ulysseus in the 90s, when there should be many more things
going on.

Sagan basically agreed with Goldin's stance, but said the natural progression
of exploration was towards more sophisticated craft- first flybys, then
orbiters, and landers.  There must be some generality in the craft, because
we won't know what we may discover until we get there.

Manned planetary exploration came up next. Goldin cited town hall audiences
enthusiastic for a manned Mars expedition in their lifetime.  Carl said there
many reasons to go to Mars, but no compelling sum of reasons to spend an
equivalent of a "S&L bailout" to make an attempt in the next decade.
Russia came up in this discussion.  Goldin outlined a number of joint US-Russian
expeditions involving cosmonaunts on each other's craft and Mir-shuttle
rondevous over the next three years.  His impression was the CIS was
very proud of its space accomplishments and it would be one of the last items
to go in a severe economic cutback.

Goldin deplored the state of NASA's public education attempts.  Said scientists
can't communicate well with the public.  TV news shows images of tin cans
blasting off and landing, but not much of what was occuring during the mission.
Said he centralizing and beefing up NASA's education and public affairs
departments.

One of the early questions from the audience accused NASA of a coverup
during the upcoming Mars Observer mission.  Flyovers of the "Face" and
pyramids were going to be encryted and classified to hide evidence of alien
intelligence.  The questioner could not say why NASA wanted to hide such
evidence.  Both Goldin and Sagan said they was no coverup.  Evidence of alien
intelligence would be welcome, although not expected.  Goldin directed JPL's
Stone to facilitate access of data to that questioner.

Scattered throughout the evening were references to national politics.
Sagan joked about Republican party follies.  Goldin said there was strong
bi-partison support of the space program.  Even Bush personally asked for
better public education.  Goldin was not partison, perhaps hoping to keep
his job in the next administration :-)

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

Date: 8 Dec 1992 20:42:55 GMT
From: steve hix <fiddler@concertina.Eng.Sun.COM>
Subject: Rush Limbaugh says problems with HST are a DoD hoax!
Newsgroups: sci.space

In article <1992Dec7.105248.1@max.u.washington.edu> games@max.u.washington.edu writes:
>In article <1992Dec4.142721.23701@mnemosyne.cs.du.edu>, dnadams@nyx.cs.du.edu (Dean Adams) writes:
>> 
>>  >The popular American radio personality Rush Limbaugh 
>> "popular"?  That doesn't say too much for the population...  :->
>> 
>>  >stated today that the problems with HSTs mirror are a Department of 
>>  >Defense hoax. 

No, he didn't.  He said that there was a *rumor* floating around to that
effect.  No indication that he believed it, as far as I could tell.

>The problem here is that people do take him seriously.  There are 100 people
>out there in the world who think that science is magic for every one of us that
>happens to know how a toaster works.  If Rush Limbaugh says it, then it must
>be true.  (After all, he has more credibility than the national enquirer, and 
>I bet we all know at least one person who belives in it!!!)

I'm amazed at at the number of things that he's supposed to have said that
conflict with what I heard him say.  (Hey, I have a 38 mile commute every

morning, and one has to find some way to deal with the commute...even if it
mean listening to Rush occasionally.  One cannot live on classical music
alone.)

Usually, the divergent reports come from people who weren't listening to
the program itself, but got some second-hand report.

If there was a station locally that played Irish and old-timey music during
the commute, I could avoid all this sort of thing...

--
-------------------------------------------------------
| Some things are too important not to give away      |
| to everybody else and have none left for yourself.  |
|------------------------ Dieter the car salesman-----|

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

Date: Tue, 8 Dec 1992 20:34:58 GMT
From: "Edward V. Wright" <ewright@convex.com>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In <1992Dec3.143759.2535@ke4zv.uucp> gary@ke4zv.uucp (Gary Coffman) writes:

>The proposed DC *is* a rocket, it *is* a low margin system as any
>SSTO has to be, and it has exactly *zero* flight history. It will
>use throttleable engines with variable geometry *based* somewhat
>on RL-10 technology at first, but radically new and never flight 
>tested. 

The engines used by every commercial airliner were "radically new"
and "never flight tested" at one time also.  Despite your claims
of "radicalism," the rocket engines are little different from those
we have been building for more than 40 years.  They are a new design,
not a new technology.

Now, please, calm down before the environmentalists attack you for
depleting the world's nonrenewable supply of asterisks.   


>Later it intends to use aerospike engine designs that have
>*never* been tested, even on the ground. 

Really?  On what do you base this statement?  The designers
at McDAC have repeatedly stated that they do not plan to use
an aerospike.


>It will be difficult for it to live up to rocket standards of 
>reliability, much less airliner standards of reliability. 

The difficult we do right away.  The impossible takes a little
longer.


>This is radically new engine and control technology being pioneered 
>on a very marginal flight article. 

Saying that doesn't make it so.  The engine is about as "radically
new" as a new microprocessor.  The control problem is the same one
that was solved, for ICBMs, in the 1960's.


>The cost and reliability levels being bandied about have no basis other
>than wishful thinking.

Sure they do.  It's called "math."

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

Date: Tue, 8 Dec 1992 20:44:10 GMT
From: "Edward V. Wright" <ewright@convex.com>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In <1992Dec4.175702.11701@ke4zv.uucp> gary@ke4zv.uucp (Gary Coffman) writes:

>I'm pointing out that what's being attempted in the X and Y tests is
>edge of the envelope high risk stuff that's not going to lead to
>airliner type vehicles any time in the near future, unless the
>tests are wildly more successful than we have any right to believe.

Yeah.  Look at jet engines.  They developed experimentally in the  
1940's, but they weren't used commercially until the 50's.

>Airliner type certification requires a degree of testing and proof
>of low risk way beyond *anything* that has ever flown in space.

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

End of Space Digest Volume 15 : Issue 525
------------------------------