Message-ID: <sb5zoIO00VcJENt05O@andrew.cmu.edu>
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Date: Sun, 14 Oct 1990 01:52:21 -0400 (EDT)
Subject: SPACE Digest V12 #458

SPACE Digest                                     Volume 12 : Issue 458

Today's Topics:
		    Re: NASA Satellite TV Coverage
		    Re: Manned/unmanned tradeoffs
		      Re: Launch cost per pound

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

Date: 8 Oct 90 18:59:06 GMT
From: bacchus.pa.dec.com!deccrl!shlump.nac.dec.com!star.dec.com!hughes@decwrl.dec.com  (Gary Hughes - VMS Development)
Subject: Re: NASA Satellite TV Coverage

There is usually a daily 'highlights' transmitted on F2/13around 8pm EDT or so
for each flight day. The length and time varies, but if you are taping these
are usually worth finding. I suspect that this is what get replayed on S1/18.

You can find the mission TV schedule on the NASA Spacelink BBS.

BTW, I noticed that F2/05 was carrying some odd frame sequential multiplexed
video before the STS-41 launch. In real time, it looked like two images
superimposed but when taped and played back in slo-mo there appeared to be
field from one source followed by two fields from another. These were regular
NTSC frames, not the wideband frame sequential color format sometimes used for
the wideband TDRSS video.

gary
hughes @star.dec.com

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

Date: 8 Oct 90 17:57:50 GMT
From: super!rminnich@uunet.uu.net  (Ronald G Minnich)
Subject: Re: Manned/unmanned tradeoffs

In article <9788@jpl-devvax.JPL.NASA.GOV> jenkins@devvax.JPL.NASA.GOV (Steve Jenkins) writes:
>There are two different concepts here: process dynamics and time delays.
>Trains and tankers have large time constants (in other words, they
>don't accelerate quickly), but there's nothing inherently difficult
>about controlling such systems ('plants' in control systems jargon).
>
>Time delays in the control input, on the other hand, particularly when
>they are not small relative to the dominant plant time constants, can
>be destabilizing.

There is a famous hill (to train people anyway) in your part of the 
country. On 100+ car freight trains the occupants of the caboose 
would put a glass of water on a table, then see if the 
engineer, as the train passed over the hill, controlled the train well
enough that no water spilled out of the glass. 

  This required a rather intricate ballet on the part of the engineer, 
with variations depending on the consist of the train (which cars were
loaded, which empty, etc.) especially considering the deceleration delay
due to air brakes and so on. In this case (there are many others--
i saw them even when i ran short trains) there were 
plant time constants that are actually pretty small, so that accurate
and careful control is important. Train control looks easy if 
you've never done it. The process dynamics of a train get tricky!

Seems to me that teleoperations to the moon is more like that environment
than flying an F-16, but you know lots more about T-O than i do.
ron
-- 
"Socialism is the road from capitalism to communism, but we never promised to 
                 feed you on the way!"-- old Russian saying
"Socialism is the torturous road from capitalism to 
                  capitalism" -- new Russian saying (Wash. Post 9/16)

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Date: 8 Oct 90 18:56:28 GMT
From: mojo!SYSMGR%KING.ENG.UMD.EDU@mimsy.umd.edu  (Doug Mohney)
Subject: Re: Launch cost per pound

In article <8304@fmeed1.UUCP>, cage@fmeed1.UUCP (Russ Cage) writes:

>Look, John.  Despite Soviet workers being paid much less, our
>productivity lets us make much more cost-effective airliners
>and road vehicles.  Possibly, our superior manufacturing
>capabilities could make Soviet-style boosters even cheaper
>than the Soviets can sell them to us.

Ok. How do I get licensed to be a certified Soviet-booster clone? You think
we could buy the blueprints to everything and get someone like GM Heavy
Equipment to build 10 launchers a year? Awww, heck with that. I'd take the
business to some place with big machine yards AND cheap labor, like South
Korea. 

Now, who wants to loan me $2 billion dollars for startup costs? ;-)

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End of SPACE Digest V12 #458
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