The X-37 B Orbital Test Vehicle (OTV) has landed at the Vandenberg Air Force Base in California, Capital Wired reports. The unmanned space drone completed its landing after 22 months in orbit. Its mission was classified and of a military purpose; the third X-37 mission to date will soon be followed up with another planned for December.

The X-37 project began as early as 1999 as a NASA project with the U.S. Air Force and Boeing’s Integrated Defense Systems. The original plan was to launch the space drone from the space shuttle but that idea was later scraped for a more cost-effective plan. Rather, the first three OTV missions have relied on the Atlas V rocket for launch.

While the purpose of the mission has not been released to the public, the vehicle is reported to be testing new space technologies. The plane appears similar to the space shuttle in aerodynamic design, although smaller and unmanned. Like the space shuttle, the X-37 returns to Earth as a spaceplane requiring a runway to land.

In fact, the X-37 will soon take up residence in the Orbiter Processing Facility at the Kennedy Space Center before its next mission, in Bays 1 and 2, most famously known for housing the space shuttles and several Saturn V rockets used during the Apollo missions.

“Kennedy is positioning itself for the future, transitioning to a multi-user launch facility for both commercial and government customers, while embarking on NASA’s new deep space exploration plans,” said Robert Cabana, director of the Kennedy Center in a statement. “A dynamic infrastructure is taking shape, designed to host many kinds of spacecraft and rockets.”