The space shuttle Columbia has disintegrated over Texas on reentry. The altitude of the shuttle was over 200,000 feet, making terrorism highly unlikely. Possibilities for the destruction of the shuttle include failure of the protective heat tiles or a change in attitude during the reentry sequence.
The casualties of this tragedy are as follows:
Shuttle commander Rick D. Husband
Pilot William C. McCool
Payload Commander Michael P. Anderson
Mission Specialists David M. Brown
May they find peace.
UPDATE: From the video footage I’ve seen, it looks like significant sections of the Shuttle come apart, possibly the wings. In any case, the effects of the disaster are hard to guess. My instinct says that the US manned space program is defunct for the next few years. Expect ISS to be abandoned in orbit with the crew ferrying home on Soyuz capsules. This leaves manned exploration of space to the Chinese, whose Shenzhou capsules will likely be ready for a manned flight this year. (The Shenzhou is a derivative of the Soviet Soyuz design.) Then again, perhaps I’m being too pessimistic. No matter what, it is important that we not allow the dream of manned exploration to die with those 7 astronauts.
UPDATE: Steven Den Beste has pictures of the astronauts while Glenn Reynolds has a large collection of information and analysis on the tragedy.