According to the news, the American space shuttle Columbia failed______. [origin

NASA officials say, on Wednesday, one of three sensors (传感器) on Columbia’s left-hand landing gear possibly indicated the device had begun to deploy (展开；配置) 30 seconds before all contact was lost with the shuttle. The new information surfaced as NASA officials were working on the latest version of the timeline covering exactly what happened before Columbia and its crew was lost on Feb. Previous timelines released by NASA and showed a number of sensors in and around the left wing were failing off or indicating a heating trend beginning eight minutes before the contact was lost.