NASA's Space Shuttle was a reusable spacecraft system that operated from 1981 to 2011. It consisted of an orbiter, solid rocket boosters, and an external fuel tank. The shuttle was designed to transport astronauts and cargo to and from low Earth orbit, including missions to the International Space Station and the Hubble Space Telescope. The Space Shuttle program completed 135 missions, enabling significant advancements in space exploration and technology. It played a crucial role in building the International Space Station and conducting scientific research in space. The program concluded with the final flight of Atlantis on July 21, 2011.