Space shuttle challenger with launch tower

Space Shuttle Challenger (OV-099) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the commanding ship of a nineteenth-century scientific expedition that traveled the world, Challenger was the second Space Shuttle orbiter to fly into space after Columbia, and launched on its maiden flight in April 1983. It was destroyed in January 1986 soon after launch in a disaster that killed all seven crewmembers aboard.
Initially manufactured as a test article not intended for spaceflight, it was utilized for ground testing of the Space Shuttle orbiter's structural design. However, after NASA found that their original plan to upgrade Enterprise for spaceflight would be more expensive than upgrading Challenger, the orbiter was pressed into operational service in the Space Shuttle program. Lessons learned from the first orbital flights of Columbia led to Challenger's design possessing fewer thermal protection system tiles and a lighter fuselage and wings. This led to it being 2,200 pounds (1,000 kilograms) lighter than Columbia, though still 5,700 pounds (2,600 kilograms) heavier than Discovery.
During its three years of operation, Challenger was flown on ten missions in the Space Shuttle program, spending over 62 days in space and completing almost 1,000 orbits around Earth. Following its maiden flight, Challenger supplanted Columbia as the leader of the Space Shuttle fleet, being the most-flown orbiter during all three years of its operation while Columbia itself was seldom used during the same time frame. Challenger was used for numerous civilian satellite launches, such as the first tracking and data relay satellite, the Palapa B communications satellites, the Long Duration Exposure Facility, and the Earth Radiation Budget Satellite. It was also used as a test bed for the Manned Maneuvering Unit (MMU) and served as the platform to repair the malfunctioning SolarMax telescope. In addition, three consecutive Spacelab missions were conducted with the orbiter in 1985, one of which being the first German crewed spaceflight mission. Passengers carried into orbit by Challenger include the first American female astronaut, the first American female spacewalker, the first African-American astronaut, and the first Canadian astronaut.
On its tenth flight in January 1986, Challenger broke up 73 seconds after liftoff, killing the seven-member crew of STS-51-L that included Christa McAuliffe, who would have been the first teacher in space. The Rogers Commission which convened shortly afterwards concluded that an O-ring seal in one of Challenger's solid rocket boosters failed to contain pressurized burning gas that leaked out of the booster, causing a structural failure of Challenger's external tank and the orbiter's subsequent breakup due to aerodynamic forces. NASA's organizational culture was also scrutinized by the Rogers Commission, and the Space Shuttle program's goal of replacing the United States' expendable launch systems was cast into doubt. The loss of Challenger and its crew led to a broad rescope of the program, and numerous aspects – such as launches from Vandenberg, the MMU, and Shuttle-Centaur – were scrapped to improve crew safety; Challenger and Atlantis were the only orbiters modified to conduct Shuttle-Centaur launches. The recovered remains of the orbiter are mostly buried in a missile silo located at Cape Canaveral LC-31, though one piece is on display at the Kennedy Space Center Visitor Complex.