Space Shuttle

The orbiter, which is manufactured by Rockwell, International, Inc., is approximately the size of a commercial DC-9 jet, with a length of 122 ft (37 m), a wing span of 78 ft (24 m), and a weight of approximately 171,000 lb (77,000 kg). Its interior, apart from the engines and various mechanical and electronic compartments, is subdivided into two main parts: crew cabin and cargo bay.

The crew cabin has two levels. Its upper level—literally "upper" only when the shuttle is in level flight in Earth's atmosphere, as there is no literal "up" and "down" when it is orbiting in free fall—is the flight deck, from which astronauts control the spacecraft during orbit and descent, and its lower level is the crew's personal quarters, which contains personal lockers and sleeping, eating, and toilet facilities. The crew cabin's atmosphere is approximately equivalent to that on the Earth's surface, with a composition 80% nitrogen and 20% oxygen.

The cargo bay is a space 15 ft (4.5 m) wide by 60 ft (18 m) long in which the shuttle's payloads—the modules or satellites that it ports to orbit or back to Earth— are stored. The cargo bay can hold up to about 65,000 lb (30,000 kg) during ascent, and about half that amount during descent.

The shuttle can also carry more habitable space than that in the crew cabin. In 1973, an agreement was reached between the U.S. National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) for the construction by ESA of a pressurized, habitable workspace that could be carried in the shuttle's cargo bay. This workspace, designated Space-lab, was designed for use as a laboratory in which various science experiments could be conducted. Each of Spacelab module is 13 ft (3.9 m) wide and 8.9 ft (2.7 m) long. Equipment for experiments is arranged in racks along the walls of the Spacelab. The whole module is loaded into the cargo bay of the shuttle prior to take-off, and remains there while the shuttle is in orbit, with the cargo-bay doors opened to give access to space. When necessary, two Spacelab modules can be joined to form a single, larger workspace.