Space shuttles are reusable spacecraft used by NASA to transport astronauts and cargo to and from space. They were in operation from 1981 to 2011, with a total of five shuttles built: Columbia, Challenger, Discovery, Atlantis, and Endeavour. The shuttles played a vital role in the construction and maintenance of the International Space Station (ISS). They were equipped with a cargo bay for carrying satellites, modules, and experiments, and they also featured a crew compartment capable of carrying up to seven astronauts. The space shuttle program brought many scientific advancements and contributed greatly to our understanding of space.