Boeing is bragging that its X-37B Orbital Test Vehicle has touched down at Vandenberg Air Force base to complete its third successful flight. We still have no idea exactly what the orbital test vehicle is being used for, but the spacecraft and its siblings are racking up some significant time spent in space. In March, another X-37B landed after spending 469 days in space. This time out, the X-37B spent 674 days in space.
Boeing says that the OTV was in orbit conducting a 674-day experimental test mission for the US Air Force Rapid Capabilities Office. This particular mission launched from Cape Canaveral Air Force Station, Florida on December 11, 2012.
The very first OTV mission began on April 22, 2010, ended on December 3, 2010, and spent 224 days in orbit. The second mission kicked off March 11 and ended June 2012, spending 468 days in orbit. Boeing says that the X-37B program is demonstrating a reusable, unmanned space test platform for the Air Force.
Objectives for the program are space experimentation, risk reduction, and concept-of-operations development for space vehicle technologies that could become key enablers for future space missions. There is no word on when the next X-37B mission might launch.