Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!web-1e.berkeley.edu!labc-4da
From: labc-4da@web-1e.berkeley.edu (Bob Heiney)
Newsgroups: sci.space.shuttle
Subject: Re: 104% thrust from SSME
Message-ID: <23778@agate.BERKELEY.EDU>
Date: 29 Apr 89 20:38:05 GMT
References: <1460@zaphod.axion.bt.co.uk>
Sender: usenet@agate.BERKELEY.EDU
Organization: University of California, Berkeley
Lines: 29

In article <1460@zaphod.axion.bt.co.uk> sjeyasin@axion.bt.co.uk writes:
>
>
>Reading the mail there appears to be several schools of thought on this:
>
>1) it is  100 + x% increase on the design spec or nominal.
>Presumably this is due to improvements in the basic design.
>
>2) it represents an operating thrust higher than what would be considered
>"peak efficiency" (with implications for saftey etc). Or as someone put it,
>"revving past the red line on the rpm counter"
>
>3) To do with the fact that on gets "more thrust the higher one goes"
>

I just read something about this, and what I believe is the correct reason
is that the engines are rated to perform to some specification at a particular
thrust.  Thus the percentage is how much of the rated thrust you're using.
Future missions are scheduled to go as high as 109% for heavy payloads
(like the Hubble telescope).

What *is* the rated thrust for the SRBs and the SSMEs?


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| Bob Heiney                         "And in the end, the love you            |
| labc-4da@rosebud.Berkeley.edu       take is equal to the love you make."    |
|                                                     -- The Beatles          |
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