The X-37B, a secretive space plane developed by the defense Department, has shattered the space flight endurance record for these vehicle designs.
The Orbital Test Vehicle 3 (OTV-3) mission is the third long-endurance trip to space. The launch, payload, and data collected by the space plane are highly-classified.
An X-37B was launched on 11 December 2012, and remains in space. On 26 March, the craft surpassed the endurance record of 469 days, set by the same model of space plane on a previous mission.
"The X-37 is a technology test bed and as such pushing the envelope is the mission. Endurance is one of several X-37 profile parameters that are being tested, along with others, such as in-flight capabilities and turnaround time for use," Joan Johnson-Freese, professor of national security affairs at the Naval War College, told Space.com.
Sources say the Air Force currently has a pair of the space planes. The one currently in space was previously used for the first test in the series. The second plane was used for the second mission.
The X-37 is only about one-quarter of the size of a space shuttle. Unlike the retired NASA spacecraft, the X-37 can operate without any humans on board. The space plane, built by Boeing, launches to space aboard an Atlas 5 rocket. Once in space, the X-37 is powered by a series of solar panels.
Each vehicle is 29 feet long, and measures 15 feet from one wing tip to another. Like the space shuttle, the X-37 uses a lifting body design, making the fuselage part of the wing. Cruising altitude for the space plane is between 110 and 500 miles. An X-37 weighs about 11,000 pounds, and can deliver about the same amount of cargo as a pickup truck.
"The vehicle was built using lighter composite structures, rather than traditional aluminum. A new generation of high-temperature wing leading-edge tiles will... replace the carbon wing leading edge segments on the Space Shuttle," the manufacturer wrote on the Web site.
Boeing is considering building a facility at Kennedy Space Center (KSC) at Cape Canaveral. The Orbital Processing Facility, a hangar once used as once used for space shuttles, is being redesigned for the X-37 project. By landing at the spaceport in Florida, The Defense Department would be able to manage flights of the space plane, start to finish, from one facility.
When the Vandenberg Air Force Base in California was adapted for the X-37, changes to the facility included replacing plates along the runaway to handle the unique landing gear of the space plane. Work on those improvements to the facility in Florida is scheduled to be completed by the middle of 2015.
Whatever the space plane is doing up there, it has been doing it for a long time.