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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.space
Subject: Re: IRAS running down
Message-ID: <3344@utzoo.UUCP>
Date: Fri, 18-Nov-83 16:19:35 EST
Article-I.D.: utzoo.3344
Posted: Fri Nov 18 16:19:35 1983
Date-Received: Fri, 18-Nov-83 16:19:35 EST
References: <13681@sri-arpa.UUCP>
Organization: U of Toronto Zoology
Lines: 14

IRAS probably needs to be refilled *before* it runs out completely,
or there is some risk of damage to its detectors from thermal shock
in warming up and then cooling down again.  There was some sort of
problem during its development -- I forget just what -- and there was
a big debate at the time about whether they should risk warming it up
to fix it.  Given this difficulty, it probably doesn't make much sense
to try to refill its liquid-helium tank unless it can be done within
the next couple of months, which is probably impractical.

I would also suspect that it is not designed for an in-space refill,
and possibly not designed to be refilled at all.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry