Space policy of the United States own use of space; and countering, if necessary, space systems and services used for hostile purposes." The Clinton policy also said the United States would develop and operate "space control capabilities to ensure freedom of action in space" only when such steps would be "consistent with treaty obligations." The Space Shuttle Columbia disaster occurred early in George W. Bush's term, leading to the report of the Columbia Accident Investigation Board being released in August 2003. The Vision for Space Exploration, announced on January 14, 2004 by President George W. Bush, was seen as a response to the Columbia disaster and
Space Shuttle of "Atlantis"s final flight on July 21, 2011. The U.S. has since relied primarily on the Russian Soyuz spacecraft to transport astronauts to the International Space Station. The Space Shuttle was a partially reusable human spaceflight vehicle capable of reaching low Earth orbit, commissioned and operated by the U.S. National Aeronautics and Space Administration (NASA) from 1981 to 2011. It resulted from shuttle design studies conducted by NASA and the U.S. Air Force in the 1960s and was first proposed for development as part of an ambitious second-generation Space Transportation System (STS) of space vehicles to follow the Apollo program