Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uwm.edu!src.honeywell.com!msi.umn.edu!cs.umn.edu!kksys!wd0gol!newave!john
From: john@newave.UUCP (John A. Weeks III)
Newsgroups: sci.space.shuttle
Subject: Re: Shuttle Status for 02/22/91 (Forwarded)
Message-ID: <677@newave.UUCP>
Date: 2 Mar 91 17:16:44 GMT
References: <1991Feb22.223855.6112@news.arc.nasa.gov> <1991Feb27.123109.540@axion.bt.co.uk>
Reply-To: john@newave.mn.org (John A. Weeks III)
Organization: NeWave Communications Ltd, Eden Prairie, MN
Lines: 40

In article <1991Feb27.123109.540@axion.bt.co.uk> sjeyasin@zaphod.axion.bt.co.uk writes:

> > - Evaluation of cracks in hinges for the external tank right  and
> >   left doors.

> Anyone able to say what these are ? Hard to imagine what kind of doors a
> tank can have.

There is a connection between the External Tank and the Shuttle.  This
connection supplies fuel from the ET in two lines (LOX and LH) and
a number of telemetry cables.  One of the fuel lines is 17" in diameter!

After the ET is disconnected from the Shuttle, the hole in the bottom
of the Shuttle has to be covered up with heat resistant tiles.  Two doors
are mounted on the bottom of the Shuttle.  These doors close after ET 
seperation.  Based on earlier discussions, it seems that the shuttle
could obtain orbit with the doors open, but loss of vehicle and loss of
crew would probably occur on re-entery.  Thus, it is very important that
these doors work properly.

Cracks were found in three of the four door hinges while Discovery was
being prepared for launch.  There were three choices--fly as-is, replace
the hinges, or install devices known as hinge-doublers.  Replacing the
hinges on the pad is fairly easy, but it is impossible to test the doors
with the ET connected to the Shuttle.  As a result, replacing the hinges
means a roll-back and de-stacking, at a cost of nearly 2 months.  Since
one of the choices was fly as-is, flight preperations continued on
Discovery until NASA decided on a solution.

Yesterday NASA announced that it has choosen to replace the hinges, so
Discovery will be rolled back.  Next up is Atlantis and the Gamma
Ray Observatory in April.

-john-

-- 
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