[meteorite-list] NASA grounds future shuttle flights

[AL Mitterling]

Hi Tom and all,

The tiles aren't sprayed on but manufactured and each has a number and 
fits at an exact place on the Space Shuttles. The Shuttle is contoured 
and so each Tile is a bit different from other tiles and why they are 
carefully numbered and placed. They use an adhesive glue (type) to 
secure the tiles. Certain tiles can take more atmospheric heat than 
other tiles. (black more heat, white less heat)

It is not uncommon for tiles to be replaced during flights. A certain 
amount of damage has always occurred to some degree but not to the 
extent that doomed the Columbia. Also they use to paint the ET (external 
tank) white. They saved money (from weight and paint) by eliminating 
that step but perhaps the paint would work to secure the foam better on 
the ET.
The reason for the foam is to insulate the cold fluids that are the 
propellants for the main engines on the inside of the ET. It also acts 
to keep the build up of ice (from humidity outside) to a minimum so it 
doesn't fall off and damage tiles or other sensitive area on the Shuttle.

I think that the news media is making more out of this than needs to be 
done. However damaged tiles under and around the shuttle that protect it 
from re-entery is a concern along with thousands of other items that can 
be catastrophic in the event problems in those areas occur.

--AL