Wmartin%OFFICE-3@sri-unix.UUCP (11/16/83)
From: Wmartin@OFFICE-3 (Will Martin) If the shuttle crew can repair other satellites, why can't they refill the IRAS helium supply and keep it running? It certainly looks to be worth it, and why throw it away and not have the benefits of such a useful device until, as the news story indicated, a "next-generation" version is launched in the 1990's? I would think that the IRAS could be refilled every n missions, or a big helium tank could be attached to it so it could run for much longer between fillings. Or are other parts of the detector degenerating so that there is more to it than the helium running out? Will Martin -------
henry@utzoo.UUCP (Henry Spencer) (11/19/83)
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