Path: utzoo!utgpu!watserv1!watmath!att!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!crdgw1!gecrdvm1!labrie
From: LABRIE@gecrdvm1.crd.ge.com
Newsgroups: sci.space.shuttle
Subject: Tiles
Message-ID: <90319.213006LABRIE@GECRDVM1.BITNET>
Date: 16 Nov 90 01:30:06 GMT
Organization: General Electric Corporate Research & Development
Lines: 38


     It may be a little late, but heres the info anyhow.

     Columbia originally used only carbon-carbon tiles for thermal protection
on re-entry (Except on the OMS pods).  I'm not sure if Enterprise had tiles
put on for testing or not.  But there is a sort of famous picture on either
Columbia or Enterprise gliding in with about a third of its tiles missing.
I remember the quote at the time being, "Looks like the cat dragged it in."
The problem was the glue used didn't penetrate into the tiles enough.  So all
the tiles were removed and glued back on.  A lot of people joked saying they
should have used Elmers Glue.  But Elmers is water soluble- big problem.

     Challenger was insulated using Nomex (?) felt insulation blankets, each
being about a square yard.  It also used tiles but only in high temperature
locations like the nose, wing tips, hinges on the bay doors, and the belly
of the shuttle.  You can expect about 500 to 1000 of these tiles to be dammaged
per flight.  Most can be repaired in place by drilling out the pits or holes,
filling with paste, and sanding smooth.  But about 100 to 150 of these will
be beyond repair and need to be replaced.  Technicians have to carefully
remove the bad tile without dammaging the surrounding tiles or the shuttle
fuselage, make a cavity casting, and ship the casting to (I think) Rockwell
so a replacement can be made.  There is no margin for error on the size.

     Repairs to the felt blankets is similar to fiber glass work on a car or
boat.  In comparison with tile repair, one square piece of blanket will take
the same amount of time to glue on as one tile.  So you can see the advantages
of the blankets.  An easy way to tell most of the tiles from the blanket
squares is, the tiles are usually black or grey and the blankets are white.


=====================================
John E. Labrie
GE Corporate Research and Development
Schenectady, New York             USA


     Views above can only be mine, no one else wants em.
     I may be crazy, But I have a gooood time!