X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
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Sat, 24 Mar 90 01:57:50 -0500 (EST)
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From: space-request+@Andrew.CMU.EDU
To: space+@Andrew.CMU.EDU
Date: Sat, 24 Mar 90 01:57:22 -0500 (EST)
Subject: SPACE Digest V11 #183
SPACE Digest Volume 11 : Issue 183
Today's Topics:
Re: Strange flash of light
guidance and navigation systems, request for literature
Disclaimer: Opinions expressed are those of the sender
and do not reflect NIST policy or agreement.
Subject: Venus balloons
>From: csusac!csuchico.edu!petunia!usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucdavis.ucdavis.edu (Brian or James)
>Subject: Re: The Amazing Flying Coilgun
> More seriously, balloons will probably be useful for research
>on planets like Venus or Titan which have dense atmospheres (I wonder
>what the lift strategy is for the cyntherian balloon, since a hot-air
>balloon would have to be hotter than the 600 degree atmosphere) and
>the gas giants, which have nothing *but* dense atmospheres.
> JDN
As I mentioned a few weeks ago, the atmosphere of Venus is ideal for balloons
(assuming an appropriate material can be found), because it is composed mostly
of carbon dioxide, and is thus very dense. Many different gases should be
buoyant in a CO2 environment (extrapolating from relative density at near-
normal pressure). Among the reasonable choices might be nitrogen, methane,
water vapor, and neon. Oxygen would be desirable since it's available locally,
but it's a little on the heavy side, and it might be too reactive.
If you can get a balloon high enough, you might be able to use the temperature
differential to power a heat engine. With sufficient heat flow, you could
even have a "hot CO2" balloon, and you wouldn't have to worry about leakage.
A chart I saw implies that the temperature drops off ~9 degrees C for every
kilometer of altitude.
The local CRC Handbook refuses to tell me the densities of these gases at
Venus surface conditions. Does anybody know? Are they still in the same ratio
as at STP?
John Roberts "They also serve who only stand and wait."
roberts@cmr.ncsl.nist.gov "They also wait who only stand and watch."
------------------------------
Date: 23 Mar 90 17:06:05 GMT
From: rochester!dietz@pt.cs.cmu.edu (Paul Dietz)
Subject: Orbital Sciences Public Offering
There's an article about OSC in today's Wall Street Journal
(page 1, left column). OSC will be completing a public offering
in the near future. My stockbroker says the price is $13/share,
but the stock is not yet trading. I've asked him to get me a
prospectus. I probably won't buy until after a successful test,
though.
Paul F. Dietz
dietz@cs.rochester.edu
------------------------------
Date: Fri, 23 Mar 90 19:57:03 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Disclaimer: Opinions expressed are those of the sender
and do not reflect NIST policy or agreement.
Subject: Comet Austin
Have there been any reports on where Comet Austin will be most easily visible?
I remember when Halley's comet came - it was reportedly very impressive in the
southern hemisphere, but hard to see in the northern hemisphere.
