"The X-37B Orbital Test Vehicle is similar to the space shuttle, except it's about a fourth the size and unmanned. The OTV can return from space on its own, said Lt. Col. Kevin Walker, an Air Force Rapid Capabilities Office program manager."Now that DARPA has the X-37 program completely under it's wing, it'll be interesting to see whether it's the USAF that manages to create the first truly re-usable and cheap launch system in human history... And not the black hole the Space Shuttle has been with NASA's guidance.
PS - Slightly ironic as well that the OTV is taking shape as a launch vehicle 1/4 the size of the Shuttle. If I'm not mistaken, it was the USAF that pushed the shuttle design to a larger size in the first place... Though that opinion is a matter of contention I think since NASA had other reasons for pushing a larger sized shuttle design.