STS-51-L was the 25th mission of the United States Space Shuttle program, and disastrous final mission of the Space Shuttle Challenger. The mission to carry out several lessons from space and observe Halley's Comet never made its target landing date of February 3, 1986. A structural failure during its ascent phase 73 seconds after launch on January 28 from Kennedy Space Center Launch Complex 39 killed all seven crew members – Commander Dick Scobee, Pilot Michael J. Smith, Mission Specialists Ellison S. Onizuka, Judith A. Resnik and Ronald E. McNair, and Payload Specialists Gregory Jarvis and Christa McAuliffe—and destroyed the orbiter. The Rogers Commission determined that the cause of the destruction was due to the failure of an O-ring seal on the starboard Solid Rocket Booster. Space Shuttle flights were suspended for 32 months while the hazards with the shuttle were addressed.