Most who follow the news know all about the reason that the Space Shuttle Columbia burned up upon re-entry. The reasons behind it are a sad tale of environmental regulations gone bad.
Columbia was doomed about 30 seconds after it took off several years ago. Chunks of foam from the external fuel tank broke or fell off, hit the wing of the orbiter and sealed the fate of our astronauts. The phenomenon of pieces of foam breaking off and hitting the orbiter is nothing new. After every takeoff there were always issues with tiny pieces of foam and other things breaking off and dinging the orbiter. Sometimes the tiles fell off themselves. The stress of takeoff is immense and those things are natural. Remember that something moving at Mach 1 can cause a whole bunch of bad things to happen to whatever it hits.
The extent of the damage starting in mission STS-87 in 1997 (the missions for the Space Shuttle are numbered, and STS stands for space transportation system - the official name for the Space Shuttle) was like nothing that had ever been seen up to that time.
But why now? Why after STS-87? Why after so many takeoffs and landings did the Space Shuttle all of a sudden have so many problems with the damn foam?
You can thank the government of the USA.
In 1987 many industrialized nations including the USA signed the Montreal Protocol. It was amended many times after that. What it says in simple English is that the nations who signed the document will agree to ramp down production of chlorofluorocarbons (CFC's), eventually to zero by Jan. 1, 1996. The science supposedly was that the CFC's, after being released into the atmosphere, damage the ozone layer and would let in more UV radiation, contributing to increased intstances of skin cancer, global warming and melting of the polar ice caps. I don't want to get into a discussion about whether the CFC's actually damage the ozone. The signing countries abided by it and that was that.
Instantly life changed for many people in many industries, including the one that I work in, heating and air conditioning. There are many different CFC's and they were used in manufacturing processes for everything from nylon to refrigerators and air conditioners to socks to de-icing planes sitting on tarmacks in winter. Oh yeah, one more thing a certain CFC was used to make. The CFC called R-11 was used to make foam. Space Shuttle external fuel tank foam.
The R-11 was one of five ingredients of the foam. It was actually not one of the ingredients of the foam itself, rather it was used as a blowing agent. What this does is create millions of bubbles so the foam solution can be "blown" (a better word may be sprayed or applied) in a smooth fashion. The foam is only one inch thick on the Space Shuttle's external fuel tanks so this solution must be applied smoothly. The R-11 facilitated this.
In 1997, NASA decided to become more environmantally friendly. They decided to move from a banned CFC blowing agent to an approved HCFC (hydrochlorofluorocarbon) blowing agent called R-141b. They could have continued using R-11, as any government agency can get a pass on environmental regulations if they really want it. But they didn't. They decided to do the environmentally correct thing and abide by the Montreal Protocol. The rest, as they say, is history. The new foam was more brittle and more broke off of the external fuel tanks than ever before. It was only a matter of time before an accident like Columbia was going to happen.