The development of a reusable transport system for NASA began in 1972 at North American Rockwell, along with a number of other companies. The total weight of the fully prepared Space Shuttle is 2,055 tons. It can carry a payload of 30 tons into an orbit up to 965 kilometers above the Earth. The orbiter prototype, the Enterprise, was completed in 1976. The Enterprise was used to explore flight and landing characteristics in the atmosphere and to develop the space-capable shuttle. The first launch of a Space Shuttle into space took place on April 12, 1981, with the space shuttle Columbia. With the completion of additional orbiters starting in 1983, NASA significantly intensified its scientific-experimental and military-strategic activities in collaboration with the U.S. Air Force. Communication and research satellites were transported into space, on-site repairs were conducted, and the American space station was built and supplied.