I'm sickened at the possibility that an attempt to minimize the shuttle's evironmental impact led to seven deaths. I wish they covered the thing with freon and spewed extra in the air for the heck of it.

Okay, I now expect someone to claim the O-ring problem was traceable to us enviros.

Try this on, instead: there's a difference between a triggering cause and a root cause. The root cause is flying humans on a dangerous machine for science that is nowhere near worth the cost. Easterbrook and Moomaw are right: forget the shuttle and the ISS. Government-sponsored manned flight shouldn't happen unless its science can compete with unmanned on a cost basis. Private space flight enthusiasts, go ahead with your own money.

As for Prometheus, I'm waiting for more information before making a final judgment on enviro risks. That's a little trick worth trying sometimes.