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From: brettvs@blake.u.washington.edu (Brett Vansteenwyk)
Newsgroups: sci.space,sci.space.shuttle
Subject: New Shuttle Engines
Message-ID: <10948@milton.u.washington.edu>
Date: 11 Nov 90 08:48:10 GMT
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Not long ago it was noted that the first of Endeavour's engines had arrived
at KSC.  Some mention was made that these engines were "new and improved".
I was hoping that more would be said to elaborate on this, but I will go
ahead and pound out a few questions...

[1].Are these new engines useable in the older shuttles?  It would seem
important considering the considerable swapping of engines and their parts
that seems to go on in the refurbishment process.

[2].Are these engines part of a more "mature" system?  In other words, has
there been a batch of changes made to the manufacture/design of these "new"
engines that will improve their servicability and ease of refurbishment?

[3].(Slight rehash from [2]).  While the SSME's have not been a particular
saftety problem (in hindsight, at least relative to the SRB's), their turn-
around launch to launch has been a nightmare for costs--so much of each
engine needs to be rebuilt.  This seems to stem from the fact that this
design pushed the envelope for efficiency and thrust to weight ratio.
This engine has been in use for almost 10 years, and it would seem
that it could be classified as a "mature" system by now--a learning curve
with subsequent reduction in refurbishment costs as well as a more reliable
engine.  Is there evidence to indicate that this has happened?  If not so
far, will these new engines allow hope for that to happen in the future?

[4].Whenever I see any discussion about new launcher development, I never,
or almost never see any suggestion to using the SSME's, nor do I see any
indication of an engine derived from SSME technology.  The tendency is
to discuss systems originating 25 or even 30 years back.  I am assuming
that the SSME was the most recent major engine development.  Has all the
time and talent spent to make the SSME work been wasted on what is now
considered an evolutionary dead-end?  While it may seem disconcerting,
it seems where the evidence is pointing.

[5].If not the evolutionary dead-end as postulated in [4], could there be
an SSME derivative for an expendable launcher, or a restartable version
for purposes similar to the Saturn 3rd stage system?  (All in all, is
it meaningful to think of derivatives of this technology since this is
the newest technology by far?) 

	Just some random thoughts.
		--Brett Van Steenwyk