The military vehicle is unpiloted and will carry out the first autonomous re-entry and landing in the history of the US space programme.

The spacecraft can return experiments to Earth for inspection and analysis.

At 9m long (29ft), 4.5m (15ft), the reusable spaceplane is about one quarter the size of the shuttle, with a large engine mounted at the rear of the ship for orbit changing.

And while the space shuttle uses a fuel cell power system; the military vehicle is powered by a solar array and lithium-ion batteries.

The precise objectives and cost of the programme are secret. But the first few flights will allow officials to evaluate the vehicle’s performance and ensure components and systems work the way they are supposed to.

It might be at this point in time that [the Air Force is] going to roll the dice and see if something good happens Dr Joan Johnson-Freese US Naval War College

“The top priority technology demonstration on this first flight is the vehicle itself,” Gary Payton, the US Air Force’s deputy under secretary for space programs, told journalists on a teleconference this week.

“Getting it into orbit, getting the payload bay doors open, the solar array deployed, learning about on-orbit attitude control and bringing it all back.”