"Mission planning." . . "Challenger (Orbiter)" . . . . "NASA programs." . . . . . . . . . . . "Report to the President : Implementation of the recommendations of the Presidential Commission on the Space Shuttle Challenger Accident"@en . . . . . . "Implementation of the recommendations of the Presidential Commission on the Space Shuttle Challenger Accident"@en . . . . . . . . . "Implementation of the recommendations of the Presidential Commission on the Space Shuttle Challenger accident report to the President"@en . . . . "Aerospace safety." . .