An unmanned space plane resembling a miniature space shuttle is expected to end a nearly two-year classified mission with a not-so-secret landing at Vandenberg Air Force Base near Lompoc, perhaps as early as Oct. 14.

One of two X-37B robotic space planes in the Air Force fleet, the California landing may be one of the last for a Boeing-built vehicle that’s been flying secret missions to test unspecified new technologies. The space plane can remain in the air for long periods drawing power from an array of solar panels.

The X-37B spacecraft is 29 feet, 3 inches long and 9 feet, 6 inches high with a wingspan of 14 feet and 11 inches, according to published reports. The X-37B weighs roughly 5.5 tons and got a ride into space on a United Launch Alliance Atlas V rocket launched from Cape Canaveral on Dec. 11, 2012.

Although there has been speculation the craft was testing space weapons or spy gear, the Air Force has declined to reveal any details about its mission. The plan “is designed to demonstrate reusable spacecraft technologies for America’s future in space and operating experiments which can be returned to, and examined, on Earth,” an Air Force statement said.

In any event, this may be one of the last landings of an X-37B at Vandenberg. The Air Force has leased space at the Kennedy Space Center in Florida and has said it plans to relocate the program there. The Air Force is also looking into whether an existing runway used to land the space shuttle in Florida could be used for landing future missions.

“Officials anticipate multiple missions will be required to satisfy the test program objectives, but the exact number of missions has not been determined,” an Air Force statement said.