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From: (Henry Spencer)
Subject: O-rings etc. (was Re: X-33/Venturestar Question...)
Date: Tue, 28 Nov 2000 15:42:39 GMT

In article <>,
rk  <> wrote:
>...I think in this
>case the joint did need to be redesigned as well as some of the test
>procedures [I recall that the pressure port was used which unseated the
>primary ring, but that's stretching the gray matter far too far! ].

O-ring seal integrity was tested with a leak-test port, giving access to
the space between the two O-rings.  Trouble was, pressurizing that space
pushed the inner O-ring inward, moving it away from the position it would
have to assume to seal the motor, and may have damaged it as well.  The
incidence of O-ring erosion rose *sharply* when NASA increased the
pressure used in the leak tests.
When failure is not an option, success  |  Henry Spencer
can get expensive.   -- Peter Stibrany  |      (aka

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