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From: katz.uci-750a%Rand-Relay@sri-unix.UUCP
Newsgroups: net.space
Subject: Re: rocket "belt" backup recovery
Message-ID: <14345@sri-arpa.UUCP>
Date: Mon, 5-Dec-83 16:55:24 EST
Article-I.D.: sri-arpa.14345
Posted: Mon Dec  5 16:55:24 1983
Date-Received: Fri, 9-Dec-83 08:36:12 EST
Lines: 22

From:  Martin D. Katz <katz.uci-750a@Rand-Relay>

David.Smith@Cmu-Cs-Ius (Dec. 2)
     ... the breathing oxygen is used for propellant.

     The current maneuvering unit does have a number of jets -- for six-axis
     control, I believe.  I don't know about extra propellant tanks.

     In my view, the dangerous possibility is not that a thruster could
     become inoperable, but that it could be jammed on, ...

Thank you, I was unaware of the details of the current NASA design of
portable propulsion.  I don't think that NASA would have approved the
routine use of breathing oxygen for other purposes a decade ago.  Is this
another cost cutting measure?

Suppose that the valve on a jet sticks open, the force can be approximately
counterbalanced by opening the opposite valve.  The remaining spin can be
negated by use of the the pair of jets which are 60 degrees from the jet
used to counteract the broken jet.  I would worry more about using up all of
that oxygen -- how long before the the pressure runs down too low for the
astronaut to breath or propel himself?