The U.S. Air Force’s secretive X-37B space plane returned to Earth on Sunday after completing more than two years in orbit.

The uncrewed X-37B Orbital Test Vehicle Mission 5 landed at NASA’s Kennedy Space Center Shuttle Landing Facility at 3:51 a.m. ET Sunday, the Air Force confirmed. The 780-day mission shattered the spaceplane’s own record of almost 718 days in orbit, which was set by Mission 4 when it returned to Earth in May 2017, Space.com reported.

X-37B MILITARY SPACE PLANE'S LATEST MYSTERY MISSION PASSES 600 DAYS

The X-37B Orbital Test Vehicle Mission 5 landed at NASA’s Kennedy Space Center Shuttle Landing Facility on Oct. 27, 2019.

The X-37B Orbital Test Vehicle Mission 5 landed at NASA’s Kennedy Space Center Shuttle Landing Facility on Oct. 27, 2019. (Air Force photo)

Mission 5 launched from Cape Canaveral Air Force Station in Florida aboard a SpaceX Falcon 9 booster on Sept. 7, 2017.

The solar-powered spaceplane was designed to spend 270 days in orbit, according to the Air Force. Space.com noted that most of its payloads remain classified.

MYSTERY MISSION: AIR FORCE'S X-37B SPACE PLANE NEARS 1 YEAR IN ORBIT

The secretive space plane completed more than two years in orbit. (Air Force photo)

The secretive space plane completed more than two years in orbit. (Air Force photo)

“The X-37B continues to demonstrate the importance of a reusable spaceplane,” said Secretary of the Air Force Barbara Barrett, in a statement. “Each successive mission advances our nation’s space capabilities.”

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The Air Force is planning to launch a sixth X-37B from Cape Canaveral Air Force Station in 2020.

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