SpaceX launches the X-37B, the Pentagon’s top-secret miniature space shuttle

In the Pentagon’s vast arsenal there is little quite like it: a super-secret space drone that looks like a miniature version of the space shuttle, but orbits the Earth for months, even years, at a time. Doing what? The Air Force won’t say.

On the tarmac, the X-37B, as it is called, looks tiny, standing not much taller than a person. Its wingspan measures less than 5 metres, and it weighs in at just 5,000kg. But over the course of six flights, it has proved to be a rugged little robotic spacecraft, spending a total of nearly six years, probing the hard environment of the high frontier.

On Thursday, after a successful morning launch at Cape Canaveral Air Force Station in Florida, the X-37B headed yet again to the vital real estate known as low Earth orbit, home to the International Space Station and all sorts of military and commercial satellites. The mission is slated to last 270 days, but the Air Force warned in a statement that “the actual duration depends on test objectives, on-orbit vehicle performance and conditions at the landing facility.”

In other words, there’s no telling how long the thing will be up there.

There’s also no telling what the spaceplane will be doing.

On a fact sheet, the Air Force says that, “the primary objectives of the X-37B are twofold: reusable spacecraft technologies for America’s future in space and operating experiments which can be returned to, and examined, on Earth.”

On this flight, the Air Force will say only that the mission is to carry small satellites, “demonstrate greater opportunities for rapid space access and on-orbit testing of emerging space technologies.” The service also said it would test experimental electronics in a weightless environment.