Space shuttles are reusable spacecraft designed to transport astronauts and cargo to and from space. They were developed by NASA and operated from 1981 to 2011. Each shuttle consisted of three main components: the orbiter, which carried the crew; the solid rocket boosters, which provided the initial thrust; and the external tank, which supplied fuel. During their missions, space shuttles played a crucial role in building and servicing the International Space Station and deploying satellites. They enabled scientific research in microgravity and contributed to advancements in space exploration. The program completed a total of 135 missions before its retirement.