Air Force’s X-37B spaceplane back on Earth after 780-day mission

The unpiloted X-37B space plane is one of two winged orbiters used to carry out classified research. With its surprise landing early Sunday morning, it closed out its record 780-day mission. This was its fifth flight in the secretive Orbital Test Vehicle (OTV) program, pushing total time aloft to 2,865 days, according to CBS News.

“The X-37B continues to demonstrate the importance of a reusable spaceplane,” Secretary of the Air Force Barbara Barrett said in a news release. This latest mission was officially called OTV-5 and was launched atop a SpaceX Falcon 9 rocket from NASA’s Kennedy Space Center Sept. 7, 2017.

The Air Force spaceplane program has been used for science experiments to test technologies in a long-duration space environment. The public may think the plane itself is classified, however, it is not. Only the experiments are classified.

A SpaceX Falcon 9 rocket carrying a secret US Air Force space plane takes off NASA's Kennedy Space Center

HO, SPACEX/AFP

The spaceplane’s planned landing Sunday was also not disclosed in advance by the Air Force, so it took everyone by surprise when it showed up this morning on NASA’s shuttle landing runway.

The X-37B executed a ground-commanded deorbit burn early Sunday to target landing at the Kennedy Space Center, then performed a series of banking maneuvers during re-entry to dissipate speed before lining up with the shuttle-era runway near Cape Canaveral.

“With a successful landing today, the X-37B completed its longest flight to date and successfully completed all mission objectives,” said Randy Walden, director of the Air Force Rapid Capabilities Office, which manages the X-37B program. “This mission successfully hosted Air Force Research Laboratory experiments, among others, as well as providing a ride for small satellites.”

Members of the X-37B recovery team, wearing hazardous material suits, approached the X-37B spaceplane for safety checks after the vehicle landed Sunday on the Shuttle Landing Facility runway at NASA’s Kennedy Space Center in Florida.

U.S. Air Force. Courtesy photo

Space News was able to get a description of one of the experiments on OTV-5. It is the U.S. Air Force Research Laboratory’s second Advanced Structurally Embedded Thermal Spreader (ASETS-II). The ASETS-II experiment is made of three low-mass, low-cost oscillating heat pipes (OHPs) and an electronics/experiment control box.

There were three primary science objectives to the experiment – to measure the initial on-orbit thermal performance – to measure long duration thermal performance, and to assess any lifetime degradation. Oscillating heat pipes are able to transport over 45 times more heat than copper, and this is just one of the technologies the Air Force is testing.

The Air Force plans to launch the sixth X-37B mission from Cape Canaveral in 2020.