. "Challenger disaster" . . . . "disaster" . . . "96" . . . . "Challenger Explosion" . "STS-51-L" . . "STS-51L" . . . . . . "last flight" . "1986-01-28" . "Challenger" . . "Space Shuttle Challenger" . "STS-51-L Interim Mishap Review Board" . . "51-L" . . . "the mission" . "Space Shuttle ''Challenger'' disaster" . "520440.0" . . . . "takeoff" . "''Challenger'' mission" . "Space Shuttle ''Challenger'' astronaut" . "Space Transportation System-25" . . "73.0" . "lost" . "launch" . . . . . "''Challenger'' disaster" . "Space Shuttle ''Challenger''" . . "STS-51-L" . "the launch" . . . "Shuttle Challenger accident" . . . . "Challenger explosion" . . . . . . "wreckage" . "1986-02-03" . . . . . "crew" . . "STS 51-L" .