Re: MMU Question

From: Henry Spencer (henry_at_spsystems.net)
Date: 03/22/05 

Date: Tue, 22 Mar 2005 18:00:46 GMT

In article <g%X%d.178296$pc5.144297@tornado.tampabay.rr.com>,
LooseChanj <really@cfl.rr.com> wrote:
>...Someone is arguing if the MMU were to fail, the poor astro is
>screwed. I'm thinking it would be relatively easy to just fly the orbiter
>over, and either grabbing him with the RMS or scooping him up in the payload
>bay...

The arm can't grab him because he doesn't have a grapple fixture. But of
course, he can grab the arm. Or the cargo bay.

Yes, this was the backup for a major MMU failure (pretty unlikely in
itself, mind you, because the MMU is highly redundant).

>And one more thing, what
>sort of failure modes did the MMUs have? What could have possibly stranded
>an astro out riding one?

Given the number of built-in backups in the hardware, the main risk was
just getting too ambitious with the maneuvers, and running out of nitrogen
for the thrusters. 

-- 
"Think outside the box -- the box isn't our friend."    |   Henry Spencer
                                -- George Herbert       | henry@spsystems.net