Scobee was assigned commander for the ill-fated STS-51-L mission. The mission, designed to deploy a satellite to study the approaching Halley's Comet and to inaugurate the Teacher in Space Project, was delayed numerous times due to bad weather and technical glitches. When the mission finally did lift off the pad, a solid rocket booster O-ring seal failure destroyed the shuttle 73 seconds into the flight, killing Scobee and the other six crew members; the disaster, viewed live on national television, prompted several days of national mourning, as well as a major shakeup at NASA. He died a lieutenant colonel. At T+68 into the mission, the CAPCOM Richard Covey informed the crew that they were "go at throttle up", and Scobee confirmed the call – his last recorded words were his response, "Roger, go at throttle up." The shuttle broke up at an altitude of 48,000 feet (14.6 km).