[Fred Mertz]

That letter must be dealt with, hard as it may or may not be.

I'm sure they're jumping through hoops to work up a response to that. Thanks for bringing it to my attention...anyway.

[Jael]

Reading these two comments gives one a different slant on the whole issue. I came across them in two differnt threads, or maybe the top one I found at Spacenews, I can't remember and I am too tired to go back and read through all of my history. But just think, if they took out the freon, and it caused this problem??????

AEDC Performs Shuttle Materials Test for NASA/Lockheed Martin

ARNOLD AFB, Tenn.
-Arnold Engineering Development Center is assisting the National Aeronautics Space Administration with improvements in existing Space Shuttle materials. According to NASA, during several previous Space Shuttle flights, including the shuttle launched Nov. 29, 1998, the shuttle external tank experienced a significant loss of foam from the intertank. The material lost caused damage to the thermal protection high-temperature tiles on the lower surface of the shuttle orbiter.
The loss of external tank foam material and subsequent damage to reentry tiles is a concern because it causes tile replacement costs to significantly increase,,u. however, it is not a flight safety issue. As a result, NASA-Marshall Space Flight Center selected AEDC to perform flight hardware materials tests on the shuttle's external tank panels in the center's von Karman Facility Supersonic Tunnel A.

The purpose was to establish the cause of failure for the tank thermal protection materials at specified simulated flight conditions. "NASA chose AEDC due to its technical expertise and historical program successes," Steve Holmes, a NASA-MSFC technical coordinator, said

A review of the records of the STS-86 records revealed that a change to the type of foam was used on the external tank.
This event is significant because the pattern of damage on this flight was similar to STS-87 but to a much lesser degree. The reason for the change in the type of foam is due to the desire of NASA to use "environmentally friendly" materials in the space program.
Freon was used in the production of the previous foam. This method was eliminated in favor of foam that did not require freon for its production. MSFC is investigating the consideration that some characteristics of the new foam may not be known for the ascent environment."

http://www.freerepublic.com/focus/news/834139/posts?page=54#54 http://www.freerepublic.com/focus/news/834139/posts?page=54#54