(Almost) Two Yrs. Before The Stars

Judging from the suits this secret mission was to shoot some Ebola to the stars to see what two yrs. of exposure to cosmic radiation might cause.

Technicians examine the X-37B unmanned space plane shortly after it landed
at Vandenberg Air Force Base in California in this Dec. 3, 2010 photo, which was provided by the military.

The Pentagon’s secret space plane, which has been orbiting Earth for nearly two years on a mysterious mission, landed Friday morning at Vandenberg Air Force Base in Santa Barbara County.

[...]

The plane, which looks like a miniature space shuttle, was launched atop an Atlas V booster from Cape Canaveral in Florida on Dec. 11, 2012.

Other theories:

Its covert mission has fueled speculation and conspiracy theories of what it has been doing for the last 22 months. Observers have hypothesized that the military could be using the robotic plane to deploy satellites or even to rendezvous with enemy satellites and destroy them.

... the secrecy surrounding the mission suggests that it was doing work for the National Reconnaissance Office, which is in charge of the nation’s intelligence-gathering satellites.

At this point as long as the junior shuttle doesn't actually drop from the skies onto my bunker (or my head if I'm caught outside) I'm not actually caring beyond wondering just how manoeuverable it is in the micro-gravity environment.