The US Air Force has launched a second experimental space plane that resembles a small shuttle.
An Atlas 5 rocket blasted off with the unmanned space plane on Saturday afternoon from Cape Canaveral, Florida.
Air Force officials were tight-lipped about the X-37B orbital test vehicle - the second of its type to be launched.
The first rocketed into orbit last spring. It landed in California in December following a 270-day mission.
The X-37B is 29-feet long with a wing span of 15-feet.
The Air Force said the newest craft will serve as a test platform for satellite sensors and systems.
Officials said the voyage will build upon what was learned during the first mission, though they are not saying what that was.
The ultimate purpose of the X-37B and details about the craft largely remain a mystery.