This Saturday, June 16, 2012 image from video made available by the Vandenberg Air Force Base shows the X-37B unmanned spacecraft landing at Vandenberg Air Force Base. The spacecraft, which was launched from Cape Canaveral Air Force Station in Florida in March 2011, conducted in-orbit experiments during the 15-month clandestine mission, officials said. It was the second such autonomous landing at the base. (AP Photo/Vandenberg Air Force Base)
This Saturday, June 16, 2012 image from video made available by the Vandenberg Air Force Base shows the X-37B unmanned spacecraft landing at Vandenberg Air Force Base. The spacecraft, which was launched from Cape Canaveral Air Force Station in Florida in March 2011, conducted in-orbit experiments during the 15-month clandestine mission, officials said. It was the second such autonomous landing at the base. (AP Photo/Vandenberg Air Force Base)