Over four years, $192 million was spent on the project, with NASA contributing $109 million, the U.S. Air Force $16 million, and Boeing $67 million. In late 2002, a new $301 million contract was awarded to Boeing as part of NASA's Space Launch Initiative framework.

The aerodynamic design of the X-37 was derived from the larger Space Shuttle orbiter, hence the X-37 has a similar lift-to-drag ratio,