Skylab was the United States' first orbiting manned space laboratory. It was launched May 14,1973, and over the following nine months served as living and working quarters for three successive crews of astronauts. Its basic module was called the orbital workshop. Attached to it were three other major sections. The Apollo telescope mount, an astronomy section, carried instruments for observing the Sun in the visible, ultraviolet, and X-ray portions of the light spectrum. The multiple docking adapter held the controls for the telescope array and provided the docking port for the Apollo spacecraft that carried the crews to and from Earth. Separating the docking adapter from the workshop was an airlock module that housed various life-support, electrical, and communications systems and through which the astronauts passed to change film in the solar telescope.