VANDENBERG AIR FORCE BASE, Calif. (AP) — A top-secret space plane has landed safely on the Southern California coast.

Officials at Vandenberg Air Force Base said the plane, which spent nearly two years orbiting Earth on a classified mission, touched down Friday morning.

The plane, known as the X-37B, resembles a mini space shuttle.

Just what the plane was doing has been the subject of sometimes spectacular speculation.

Several experts have theorized it carried a payload of spy gear in its cargo bay.

Other theories sound straight out of a James Bond film, including that the spacecraft would be able to capture the satellites of other nations or shadow China’s space lab.

The military isn’t saying.

The X-37B program has bounced between several federal agencies, NASA among them, since 1999.