Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!gatech!prism!ccsupos
From: ccsupos@prism.gatech.EDU (SCHREIBER, O. A.)
Newsgroups: sci.space.shuttle
Subject: Re: Why 3 SSME's?
Message-ID: <2152@hydra.gatech.EDU>
Date: 28 Sep 89 22:04:15 GMT
References: <24@loop.UUCP> <1979@hydra.gatech.EDU> <4337@wpi.wpi.edu>
Reply-To: ccsupos@prism.gatech.EDU (SCHREIBER, O. A.)
Organization: Georgia Institute of Technology
Lines: 37

In article <4337@wpi.wpi.edu> tmurphy@wpi.wpi.edu (Tom [Chris] Murphy) writes:
>>albeit in the form of escape towers. It seems to me that you don't
>>just design a manned space vehicle by being satisfied with a
>>percentage of catastrophic failure low enough, you ought to
>>supply a backup escape system at least in the most traumatic 
>>sequence of flight (vertical ascent).
>
>It seems to me that manned aircraft are designed exactly like this, by
>keeping a failure rate low.  
>Perhaps this is a bad approach, but if it's
>good enough for commercial aircraft, 
>it should be valid for spacecraft as well

I would like to know how low the percentage of catastrophic
failure was for the shuttle when they sized its reliability.
I think that they cannot make it as low as that of an airliner 
because of the vertical take off phase which involves
by definition enormous thrust levels. This
is why I say that they should have kept the concept of the
escape system... or gone to a horizontal take off configuration.

>Back when NASA was choosing contractors for the SSME, Pratt & Whitney
>had a 2MN LH/LOX engine on the shelf;  NASA went with Rocketdyne for
>political reasons.

For what market did P&W intend its product
or why was it ready so much earlier than Rocketdyne's?

Olivier Schreiber (404)894 6147, Office of Computing Services
Georgia Institute of Technology, Atlanta Georgia, 30332
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-- 
Olivier Schreiber (404)894 6147, Office of Computing Services
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp: ...!{allegra,amd,hplabs,seismo,ut-ngp}!gatech!prism!ccsupos
ARPA: ccsupos@prism.gatech.edu