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From: dil@mace.cc.purdue.edu (Perry G Ramsey)
Newsgroups: sci.space.shuttle
Subject: Re: Tiles
Summary: Wrong on several counts
Message-ID: <6108@mace.cc.purdue.edu>
Date: 17 Nov 90 23:12:43 GMT
References: <90319.213006LABRIE@GECRDVM1.BITNET>
Organization: Department of Earth and Atmospheric Sciences
Lines: 57

In article <90319.213006LABRIE@GECRDVM1.BITNET>, LABRIE@gecrdvm1.crd.ge.com writes:
>      Columbia originally used only carbon-carbon tiles for thermal protection
> on re-entry (Except on the OMS pods).

All the vehicles use carbon-carbon , but only on the nose and the leading edge
of the wings.  It's the gray stuff.  The black and white tiles are silica
fibers which have been sintered to form a little brick.  The black ones
have a different coating, so they will emit more radiation at high
temperatures.  The top of the doors and some and a few other places are covered
with a nomex felt which is covered with a white coating.  This is known as
FRSI (Flexible Reusable Surface Insulation.)

> 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.

The glue held fine.  The tile was too thick to stand the load and split.
Densification increased the density of the tile and it's strength near
the glue line.
> 
>      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. 

Challenger's TPS was not radically different from Columbia's, with the exception
of the wing glove area.  It's black on Columbia, white on Challenger.

Discovery and Atlantis use AFRSI (Advanced FRSI.  What are they going
to call the stuff that's more advanced than AFRSI?  But I digress.)
in moderate temperature areas like the
sides of the vertical stabilizer and the top of the wing.  This is a small
blanket about 1 ft square, and is about 1 in. thick.  It is full of glassy
fibers.

> 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.

Lockheed.  There is a significant gap between each tile to accomodate thermal
expansion, and a variety of devices to fill gaps.

> 
>      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.

Discovery and Atlantis have a lot of white tiles.  Challenger and Columbia
had/have a lot more.

> John E. Labrie
-- 
Perry G. Ramsey           Department of Earth and Atmospheric Sciences
perryr@vm.cc.purdue.edu   Purdue University, W. Lafayette, IN USA
dil@mace.cc.purdue.edu   
 Why waste time learning when ignorance is instantaneous?  -- Hobbes