Challenger disaster, explosion of the U.S. space shuttle orbiter Challenger, shortly after its launch from Cape Canaveral, Florida, on January 28, 1986, which claimed the lives of seven astronauts. The primary goal of shuttle mission 51-L was to launch the second Tracking and Data Relay Satellite (TDRS-B). It also carried the Spartan Halley spacecraft, a small satellite that was to be released by Challenger and picked up two days later after observing Halley’s Comet during its closest approach to the Sun. Greatest visibility among the crew went to teacher-in-space Christa McAuliffe of Concord, New Hampshire, the winner of a national