Path: utzoo!utgpu!attcan!uunet!pyrdc!pyrnj!rutgers!att!ihlpl!knudsen
From: knudsen@ihlpl.ATT.COM (Knudsen)
Newsgroups: sci.space.shuttle
Subject: Re: Heavy Lift Capacity Boosters
Summary: Good thinking.  Long-running SSMEs?
Message-ID: <6871@ihlpl.ATT.COM>
Date: 23 Sep 88 17:44:12 GMT
References: <677@eplrx7.UUCP> <2240@ssc-vax.UUCP>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 36

In article <2240@ssc-vax.UUCP>, eder@ssc-vax.UUCP (Dani Eder) writes:
>      It is possible to make a variety of cargo launchers using the propulsion
> elements of the Space Shuttle, but without carrying an orbiter.  The
> elements available are the Solid Rocket Boosters and the Space Shuttle
> Main Engines.  By varying the number of segments in the SRBs and the
> number of SSMEs used, you can get different payloads.  For reference,
[table of combinations dfeleted]

Well, this is good thinking and the first time I've seen it spelled
out this way.  Use SSMEs as the base (literally and figuratively)
for a new series of heavy launchers.

One suggestion:  Seems that what distinguishes the SSMEs from
earlier liquid engines is their longevity -- designed for re-use,
and test-fired for over 30 minutes.

So any alternate plans for these engines should try to exploit
this special feature.  Staged rockets tend to burn for only a few minutes,
while strap-on-boosted rockets (like the Shuttle) can burn longer.

Are there any applications where a single engine that burns for
over 20 minutes would be especially helpful?  Like a Mars or
deep-space probe (a big one), or something really huge
into Clarke orbit?


About the SRBs -- adding a segment makes it burn harder, not longer,
for more thrust in the same time.  I'd like a little more confidence
in the nozzles and joints before we up the pressure on the one
Shuttle component know to have failed disastrously.

On the other hand, dropping one segment (3 segs) might give a
very safe booster.

BTW, to use up those pre-51L SRBs, strap them onto something,
but not an Orbiter, please.