Newsgroups: sci.space.policy
From: henry@spsystems.net (Henry Spencer)
Subject: O-rings etc. (was Re: X-33/Venturestar Question...)
Date: Tue, 28 Nov 2000 15:42:39 GMT

In article <3A1AB6B6.AED2106D@nospamplease.erols.com>,
rk  <stellare@nospamplease.erols.com> 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   henry@spsystems.net
can get expensive.   -- Peter Stibrany  |      (aka henry@zoo.toronto.edu)