Thursday, July 28, 2005

Space Shuttle Blogroll

Professor Reynolds fowards us to three blog posts on the space shuttle talk:

1) Rand Simberg
2) California Yankee
3) Mike's Noise

Here's an excerpt from Mike's Noise:

But here is what no one seems to be talking about - the problems with foam peeling and breaking off the main fuel tank are relatively new. In 1997, NASA bent to pressure from environmental groups and began using a new type of foam on the main fuel tank.

Why all the fuss? Because the traditional foam insulation, the product that had been specified in the 1970 Shuttle designs, the product that was used up until 1997, was made by injecting polymer with chlorofluorocarbons -- "freon" -- compounds whose use was severely limited under the 1991 Montreal Protocol. With the adoption of this protocol by the U. S., the Environmental Protection Agency set target dates for major industries to phase out the use of freon.

After the new foam was used on Columbia mission STS-87 in November 1997, post-flight examination of the craft found that 308 of the special heat-absorbent ceramic tiles that cover the Shuttle's outer skin were damaged. The average number of damaged tiles for previous missions was 40. NASA engineers immediately suspected that the new insulating foam was breaking loose, but NASA supervisors were apparently more interested in impressive, successfully-completed missions than in adequate mission safety. The peeling foam was written off as a negligible risk.


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