X-37B Secret Space Plane Had 7 Collisions With Debris While In Space.

According to Defense Department spokesman Richard McKinney. There were multiple collisions with space debris during the X-37's 244 days in space.

The only physical damage seen so far has been seven areas where space debris collided with the aircraft. It also blew out a tire upon landing. McKinney, meeting with reporters at the Pentagon on Monday, said he wasn't sure if that stemmed from a collision on the runway, a problem with the tire itself or something else.

"This is a test vehicle to prove the materials and capabilities, to put experiments in space and bring them back and check out the technologies," he said. "My words to others who might read anything else into that is 'just listen to what we're telling you.'"

"This is, pure and simple, a test vehicle so we can prove technologies and capabilities."

Still, the experiments placed on board the spacecraft and the program's budget remain classified.

McKinney stressed the X-37B remains an experimental aircraft – and it's still too early to draw too many conclusions about the program.

"Test aircraft have hundreds, if not thousands of test flights," he said. "We've had one flight. We are really at the very beginning of this."