The Associated Press

On Jan. 28, 1986, seven crew members, including a New Hampshire schoolteacher, took off aboard the Space Shuttle challenger from Kennedy Space Center.

Seventy-three seconds later, the shuttle disintegrated in the sky. All crew members, including New Hampshire teacher Christa McAuliffe, were killed while millions watched on live television.

On Saturday, space shuttle Columbia apparently disintegrated in flames over Texas minutes before it was to land Saturday.

A gas leak in the right booster rocket was blamed for the Challenger blast. In the explosion, the crew module separated intact from the fireball, went into a 21/2-minute free fall from 50,000 feet and plunged into the sea.

The crew members had no parachutes and no way to jettison the hatch.

The public embraced the crew members, including McAuliffe; commander Francis R. (Dick) Scobee, pilot Michael J. Smith; specialists Judith A. Resnik, Ronald E. McNair and Ellison S. Onizuka; payload specialist Gregory B. Jarvis, a Hughes Aircraft Corp. employee.

McAuliffe was selected from among more than 11,000 teachers who applied for the Challenger mission. She was chosen by NASA in 1984 and took a leave of absence that fall to train for the mission.

NASA put the shuttle program on hold after the Challenger accident until 1988. The agency has put the odds of a catastrophic accident during launch - the most dangerous part of any shuttle mission - at 1 in 438.

NASA: www.hq.nasa.gov/office/pao/History/sts51l.html