"The X-37B OTV is designed for an on-orbit duration of approximately 9 months, " said Lieutenant Colonel McIntyre.

ENGADGET: USAF relaunches its first X-37B on a slightly less mysterious spaceflight

"This mission will incorporate the lessons learned during the refurbishment process on OTV-1, " said Lieutenant Colonel McIntyre.

ENGADGET: USAF relaunches its first X-37B on a slightly less mysterious spaceflight

The launch comes on the heels of the successful flight of OTV-2, which made an autonomous landing at Vandenberg Air Force Base, Calif.

ENGADGET: USAF relaunches its first X-37B on a slightly less mysterious spaceflight

OTV-1 launched in April 2010 and spent 224 days in orbit before going through the refurbishment process prior to being prepped for this mission, he said.

ENGADGET: USAF relaunches its first X-37B on a slightly less mysterious spaceflight