It appears the space shuttle Columbia exploded or disintegrated upon re-entry this morning, over the state of Texas. NASA reports they lost contact around 9 AM EST. Dave's doing a superb job of collecting facts as the news comes in. It was January 28, 1986 that Challenger exploded 72 seconds after launch, with Christa McAuliffe, the first teacher in space, aboard. 17 years and 3 days later, Columbia explodes on return, with Col. Ilan Ramon, the first Israeli astronaut and Kalpana Chawla, the first Indian-born woman, on board.