A secretive space plane returned to Earth on Sunday with a sonic boom.
The U.S. Air Force’s unmanned, reusable vehicle landed at NASA’s Kennedy Space Center after spending a record 718 days in space. Powerful shock waves rippled throughout Central Florida as the mini-space shuttle returned from its mission.
The X-37B Orbital Test Vehicle (OTV) is the military’s newest and most advanced re-entry spacecraft. It’s part of a broader U.S. strategy to develop out-of-this-world technologies that can be used for multiple launches and landings.
This Earth-circling mission is the program’s fourth since April 2010, giving it the moniker OTV-4.
“Today marks an incredibly exciting day for the 45th Space Wing as we continue to break barriers,” Brigadier General Wayne Monteith, who commands the space wing, said in a statement.
Most X-37B payloads and vehicles are considered classified, so it’s not completely clear what the Air Force is doing with these space planes.
But the Air Force says it has two main objectives: Conduct operating experiments that can be returned to and further studied on Earth, and test reusable spacecraft technologies to support “America’s future in space.”
The latter goal is also a major focus of private space outfits like Elon Musk’s SpaceX, which considers the reusability of spacecraft a huge part of its business plan.
In late March, the company made history when it relaunched a previously flown Falcon 9 booster.
The Air Force’s X-37B program includes two X-37B planes built by Boeing. Both of them measure 9 feet 6 inches high and are 29 feet 3 inches long. They weigh 11,000 pounds at launch and use gallium-arsenide solar cells with lithium-ion batteries for power.
The OTV-4 conducted experiments for 718 days while orbiting the Earth, extending the program’s total number of days spent on-orbit to 2,085 days, the Air Force said. OTV-1 spent 224 days in space, while OTV-2 and OTV-3 operated for 468 days and 675 days, respectively.
This fourth mission is the first to land at NASA’s shuttle landing facility on Florida’s Merritt Island. The first three missions all landed successfully at Vandenberg Air Force Base in Lompoc, California.
“We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities,” Lieutenant Colonel Ron Fehlen, the X-37B program manager, said in a statement.
The Air Force said it is preparing to launch its fifth X-37B mission from Cape Canaveral Air Force Station in Florida later in 2017.