The reusable space plane will launch atop a SpaceX Falcon Heavy rocket from NASA's Kennedy Space Center in Florida on Dec. 7 for its seventh overall mission, designated USSF-52. 

This marks the first time that the X-37B will launch on a Falcon Heavy, according to a Space Force statement. Little is known about the capabilities and operations of the space plane, but Space Force says the mission will follow previous flights that used the X-37B as a test bed for launching experimental payloads and returning them to Earth.

"We are excited to expand the envelope of the reusable X-37B's capabilities, using the flight-proven service module and Falcon Heavy rocket to fly multiple cutting-edge experiments for the Department of the Air Force and its partners," said Lt. Col. Joseph Fritschen, program director for the X-37B, in the statement.

It isn't known why the X-37B is launching atop a Falcon Heavy for the USSF-52 mission. Five of the space plane's previous missions launched on United Launch Alliance Atlas V rockets, while its fifth mission, USA-277, took off on top of SpaceX's smaller rocket, the Falcon 9 (Falcon Heavy consists of three Falcon 9 boosters strapped together). 

Such a change could suggest that the space plane is carrying heavier payloads or is sporting a new hardware configuration. So far, Space Force has only stated that the mission will "expand the United States Space Force's knowledge of the space environment by experimenting with future space domain awareness technologies," according to the statement.