Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!cs.utexas.edu!uunet!bfmny0!tneff
From: tneff@bfmny0.UU.NET (Tom Neff)
Newsgroups: sci.space.shuttle
Subject: Re: LDEF
Message-ID: <14891@bfmny0.UU.NET>
Date: 10 Nov 89 01:14:45 GMT
References: <3115@jhunix.HCF.JHU.EDU> <1989Nov1.024354.6148@utzoo.uucp> <8635@microsoft.UUCP> <14861@bfmny0.UU.NET> <8739@microsoft.UUCP>
Reply-To: tneff@bfmny0.UU.NET (Tom Neff)
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In article <8739@microsoft.UUCP> bobal@microsoft.UUCP (Bob Allison) writes:
>That article in SciAm about Space Shuttle glow was pretty interesting: yet
>another reason we don't want to be in quite-that-low-earth-orbit. 

Wasn't it though!  I was going to post about it but procrastinated.
The gist: LEO is definitely *in* the atmosphere -- a billion atoms
per cubic centimeter, much of it monatomic oxygen which proves HIGHLY
reactive on all sorts of surfaces.  Kapton film, used for many structural
purposes because of its strength and lightness, erodes at several mm/yr.
The films supporting the Space Station solar array, as currently planned,
might be gone in a year!  Coatings disappear, clear plastic turns opaque,
and the black-painted shuttle tail *glows* visibly yellow at night when
it's facing the wind.

>                                                                   Looks
>like they've incorporated some changes into HST for it, though.

The paint that glows so brightly will no longer line the optical tube :-)
Let's hope we know enough about what else can happen.

I wonder if the cradle they're building for LDEF will work if it's HALF AN
INCH SMALLER in diameter as is possible extrapolating some of the SciAm
numbers...
-- 
When I was [in Canada] I found their jokes like their   | Tom Neff
roads -- not very long and not very good, leading to a  | tneff@bfmny0.UU.NET
little tin point of a spire which has been remorselessly
obvious for miles without seeming to get any nearer. -- Samuel Butler.