But another ironic thing to consider - the regulations prohibiting Freon used in making insulation -EXEMPTED NASA.
Problem is - NASA is on the ozone hole scare, figuring more money there. So NASA has chosen to be politically correct, and while they could have chosen to continue insulating the external tank in the old way (using Freon) - NASA decided to set a good example and drop using Freon.
The NASA people who made this choice are responsible for the loss of the Shuttle Columbia - because there was ample evidence before its loss (starting in 1997) that the new style foam caused problems. Rather than fixing the problem by going back to what worked ... they ignored it!
Mike
Did the original shuttle design include foam insulation?
This is a good point, but NASA and other defense contractors were not really "exempted". Their management were told that if they could not find a more environmentally friendly process then the old process could be kept by filing a petition to the EPA that would say in plain language: " We are too dumb or we don't care for the environment, or we are just too lazy so can we keep our old process?" It is not surprising that companys took the approanch that no petitions would be sent.
The last thing is that materials scientists were the ones who suggested alternate compounds. Like for example using ethanol (alcohol) as a degreaser/cleaner in place of Methyl Ethyl Ketone. (MEK worked a h*ll of a lot better but with patience and scrubbing it was considered that alcohol would work as well.) This was the dumb logic of the time. It also removed some safety hazards from the manufacturing areas and the companies benefitted from lower workers compensation costs as a result. But material scientists were not the same engineers responsible for the safety of the shuttle, (or in general the engineering specifications of the design). Often the adhesion requirement was not a well understood by the materials scientists as the mechanical engineers who had to use approved processes even when they did not understand the degree of testing and control that the process required. In the case of many of these processes, the technician doing the job had a huge influence on whether the process worked or not. I.E. what works in a lab may not work on the manufacturing floor.
But the fact is that NASA could have petitioned for their process but did not. In fact defense contractors made great PR by claiming they were 100% compliant with these new environmentally friendly regulations, and the PC government awarded gold stars while program after program suffered losses and failures as a result. The Colombia was simply a higher profile disaster so it got our attention.