Re: Mir, Atlantis

Philip Chien (
Sun, 31 Mar 1996 07:38:55 -0400

Tristan Cools asks:

>I had a last chance to observe Mir and Atlantis(and Hyakutake...) this
>(early) morning.  At 0318UT the first and most brilliant object(which I
>presume was Atlantis) was preceding what was probably Mir with a distance of
>about 32 degrees.   I was very much surprised by the brightness of Atlantis
>which reached magnitude -3.  Does anyone know in which mode they were flying
>?  Were they flying with the payload doors open or closed ?

The payload bay doors are always opened as soon as the shuttle arrives on
orbit, and only closed shortly before reentry.  The radiators are located
on the inside surfaces of the doors, and a necessary part of the shuttle's
cooling system.  When the doors are closed, or the heat loads are too high
for the radiators, a flash evaporator system boils water to remove heat.
In addition there's an ammonia system for heat rejection during reentry.

Which goes to explain why NASA was so concerned when there was a minor
problem with opening up the payload bay doors after the landing scrub -- it
is a major concern.  But the door latch problem was probably just a
malfunctioning microswitch.  *sigh* - it's always the little things in life

>The second object(Mir ?) had a brightness of magnitude -1.

Philip Chien, Earth News - space writer and consultant  PCHIEN@IDS.NET
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