Space Shuttle Challenger (NASA Orbiter Vehicle Designation: OV-099) was NASA's second Space Shuttle orbiter to be put into service, after ''Columbia''. Its maiden voyage was on April 4, 1983, and it made eight further round trips to low earth orbit before breaking up 73 seconds after the launch of its tenth mission, on January 28, 1986, killing all 7 crew members. (For more on the Challenger disaster, see Space Shuttle Challenger disaster.) It would be replaced by the space shuttle Endeavour, launched six years after the 51-L disaster.

Challenger was constructed using a body frame (STA-099) that had initially been built as a test article. STA-099 had not been meant for spaceflight, but NASA discovered that recycling it would be less expensive than refitting the test shuttle ''Enterprise'' (OV-101) to be spaceworthy, as originally planned. The spacecraft was named after a British corvette which carried out a pioneering global marine research expedition in the 1870s*. Unlike Columbia, Challenger was the first Orbiter to be delivered with fewer tiles on its Thermal Protection System. Most of the tiles were replaced with DuPont white nomex felt insulation on the payload bay doors, upper wing surface and rear fuselage surface, allowing Challenger to carry 2,500 lbs. more than Columbia. It was also the first Orbiter to have a heads-up display system similar to those found in military and newer civilian aircraft to allow the commander and pilot to see important data during reentry and landing, eliminating the need to look at the instrument panel during descent and allowing them to concentrate on flying the Orbiter.



Challenger, along with Discovery was modified at KSC to be able to carry the Centaur-G upper-stage in its payload bay. Had STS-51-L been successful, Challenger's next mission would have been the deployment of the Ulysses probe with the Centaur to study the polar regions of the Sun.

Challenger was one of two space shuttles destroyed in an accident during a mission, the other being Columbia. The collected debris of the vessel is currently stored in decommissioned missile silos at Cape Canaveral Air Force Station. From time to time, further pieces of debris from the orbiter wash up on the Florida coast. When this happens, they are collected and transported to the silos for storage.