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From: gandalf@pro-canaveral.cts.com (Ken Hollis)
Newsgroups: sci.space.shuttle
Subject: Re: Shuttle Tiles...
Message-ID: <5735@crash.cts.com>
Date: 19 Nov 90 22:36:02 GMT
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Greetings and Salutations:

>From: henry@zoo.toronto.edu (Henry Spencer)
>Subject: Re: Shuttle tiles
>In article <17415@thorin.cs.unc.edu> ornat@ornat.cs.unc.edu (Steven Ornat)
write
>s:
>>Does NASA still have to replace tiles on the shuttle after they
>>return or has that problem been solved?
>
>The tiles generally no longer fall off -- just as well! -- but still suffer
>minor damage during takeoff and landing.  A few dozen tiles are replaced

For STS - 41, Flight 11 OV-103 (Ulysses) 11 tiles were replaced because of
damage (one from window #6 R&R last flow).  There were 16 impacts of 1" or
greater, 76 total impacts.

>after each mission, usually because of surface nicks and dents.
>
>The really labor-intensive part of the tiles -- inspecting, testing the
>strength of the bond to the orbiter skin, and measuring edge gaps for
>*each and every tile* after each mission -- continues, however.  It has

The inspection / replacement process consists of the following:

Inspect the tiles on the ship and write a problem report on each that has any
defect.  The disposition falls basically into two categories:

1) Minor repairs : A gray "slurry" is baked onto the surface for those areas
where minor nicks / dings have taken place.

2) Major repairs: A "Splash" mold is made of the removed tile, sent to
Lockheed & the new tile fabricated, sent back and installed.  A pull test is
performed ONLY on those tiles replaced, and the associated gap fillers &
thermal barriers, not on every tile.

All blankets & tiles are waterproofed (used to be ScotchGuard, don't know what
it is now...).  This insures that the face of the tile does not pop off
because of water that has soaked into the tile & blankets that freezes &
breaks the tile on ascent.  

>been reduced a bit by using large one-piece blankets rather than small
>tiles in low-temperature areas.

One-piece blankets are FRSI (Felt Reusable Surface Insulation), FIB (Flexible
Insulation Blankets), & TCS (Thermal Control System) Blankets

>"I don't *want* to be normal!"         | Henry Spencer at U of Toronto
Zoology
>"Not to worry."                        |  henry@zoo.toronto.edu   utzoo!henry
>

Ken Hollis

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