20 years after space shuttle Columbia disaster, lessons learned still in sharp focus at NASA

Twenty years ago this Wednesday — on Feb. 1, 2003, at 8:48:39 a.m. EST — a sensor in the space shuttle Columbia's left wing first recorded unusual stress as the orbiter and its seven crew members headed back to Earth to close out a successful 16-day science mission.

Over the next 12 minutes, an on-board data recorder would track a cascade of alarming sensor readings and failures on the left side of the spacecraft that indicated a rapidly escalating catastrophe as the blazing heat of re-entry engulfed the ship.

But it initially played out behind the scenes in the ship's fight computers, which waged an increasingly desperate struggle to keep Columbia on track for a planned landing at the Kennedy Space Center in Florida where friends and family were waiting.