Mini shuttle heads home

A miniature robotic space shuttle launched from Cape Canaveral in April has completed a nine-month classified mission for the US military and will be headed for a landing as early as tomorrow.

The vehicle, known as the Orbital Test Vehicle, or X-37B, is expected to land at Vandenberg Air Force Base in California between tomorrow and Monday, depending on weather and technical considerations, the Air Force said in a statement.

The project, started by Nasa in the late 1990s and later adopted by the military, is intended to test technologies for a next-generation space shuttle.

The military is looking at the space plane as a way to test new equipment, sensors and material in space, with the intention of incorporating successful technologies into satellites and other operational systems.

The Air Force imposed a news blackout on the X-37B's activities while it was in orbit, although it was tracked by amateur satellite-watchers throughout the nine-month mission.

The X-37B looks like a space-shuttle orbiter, with a similar shape and payload bay for cargo and experiments. But it measures 8.9m in length and has a 4.5m wing, compared with the 37m orbiters with wing spans of 23.8m.

Unlike Nasa's space shuttles, which can stay in orbit for about two weeks, X-37B is designed to spend as long as nine months in space, then land autonomously on a runway.

The Air Force plans to fly its second X-37B vehicle next year.

The vehicles were built by Boeing's advanced research lab, Phantom Works.