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From: phil@titan.rice.edu (William LeFebvre)
Newsgroups: sci.space.shuttle
Subject: Re: Shuttle Payload Capacity
Message-ID: <3108@kalliope.rice.edu>
Date: 17 Apr 89 22:06:11 GMT
References: <1521@fredonia.UUCP>
Sender: usenet@rice.edu
Reply-To: phil@Rice.edu (William LeFebvre)
Organization: Rice University, Houston
Lines: 21

In article <1521@fredonia.UUCP> behr8762@fredonia.UUCP (Mike Behr) writes:
>     The shuttle main engines during flight are used at 104% rated thrust.
>I understand the maximum rated thrust is 109% (correct me if I'm wrong)

That's correct.

>but have not to my knowledge been throttled to 109% since the shuttle has
>been operational.  Does anybody know why - is it because the engine
>hardware will be pushed to their limits increasing the chances of
>catastrophe???

Certain scenarios that involve loss of an SSME are considered catastrophic.
If one of those was to fly apart at full throttle, there's no way to predict
what damage it could do.  They have noticed problems in the past with main
engines and are probably a little nervous about them.  Why push it when you
don't have to?

			William LeFebvre
			Department of Computer Science
			Rice University
			<phil@Rice.edu>