Good God. We just lost another space shuttle.
Apparently Columbia broke up at an altitude of over 200,000 feet, while travelling at Mach 18. CNN is showing videos of the shuttle breaking up in a cloud of flaming debris, and pieces have been falling over the South, from TX to LA, right along the landing trajectory.
NASA says that a launch video shows a piece of insulated foam falling from the external tank and striking the wing during ascent, but saw no reason for concern. My initial piece of uninformed conjecture is that the extreme stresses of launch and landing, combined with the age of Columbia’s 22-year old frame, may have exacerbated the effects of the impact into massive structural failure at some sensitive spot, exposing combustible material to the exterior so that the ram-pressure heat of reentry sparked an explosion.
My prayers go out to the families of the crew, and even now I hope against all cosmic unlikelihood for a miraculous survival.
Update: Ron Dittemoor, NASA shuttle program manager, has just spoken on the news. I only hear these words: “Sudden loss of … indicator in left wing … left wing … tire pressure in left main gear … left inboard and outboard hydraulic systems … left wing …”