This all started right after they quit using the politically incorrect freon to apply the foam on the external tank. Their inability to go back to that method (political correctness) is going to shut them down, but not until they kill a few more.
this is a myth that dies hard.......
http://www.sts107.info/kooks%20and%20myths/kooks.htm#EPA
Myth - Left wing environmental policies doomed the shuttle
According to some claims, EPA regulations that eliminated Freon caused the foam to fall off.
CFC-11 Freon was used to apply the Spray On Foam Insulation (SOFI) to the ET, and the formula was changed because of EPA regulations. The new method did result in more foam falling off and hitting the shuttle, most notably STS-87, which had 308 damaged tiles, but that was not the type of foam which doomed Columbia.
In the mid-1990s, the EPA banned CFC-11 Freon. NASA has many waivers from the EPA for critical items. In each case a commercial supplier is licensed to produce the limited quantities NASA needs, but it’s incredibly expensive to manufacture the relatively small quantities just for one customer. Lockheed-Martin went through a major effort to find a more environmentally friendly propellant. (It wasn’t something they wanted to do, but a necessity.) They selected HCFC 141b (Dichlorofluoroethane). HCFC 141b is only used to spray acreage foam –applied to the large cylindrical surfaces with a giant robotic sprayer.
The bipod foam which doomed Columbia was BX-250 foam, which was excluded from that EPA mandate. Technicians built the bipod by hand, layer by layer, and carved it into shape. The manufacturing process for the bipod and its chemical composition did not change and still used CFC-11. No changes to environmental regulations caused the Columbia accident.
So true.
An application of so called “enviro- friendly” (which usually translates to “sub-standard”) foam has cost some lives already.
NASA is culpable.