In 1999, NASA selected Boeing Integrated Defense Systems to design and develop an orbital vehicle, built by the California branch of Boeing's Phantom Works. Over a four-year period, a total of US$192 million was spent on the project, with NASA contributing US$109 million, the U.S. Air Force US$16 million, and Boeing US$67 million. In late 2002, a new US$301 million contract was awarded to Boeing as part of NASA's Space Launch Initiative framework. The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004. Thereafter, the program became a classified project. DARPA promoted the X-37 as part of the independent space policy that the United States Department of Defense has pursued since the 1986 Challenger disaster.