US Air Force's Secret X37-B Space Plane Launches on Fourth Mission

PHOTO: In a testing procedure, the X-37B Orbital Test Vehicle taxis on the flightline, June 2009 at Vandenberg Air Force Base, Calif.PlayU.S. Air Force
WATCH Air Force's Space Plane Returns to Earth After Secret Mission

A secretive space plane owned by the United States Air Force launched this morning on its fourth mission to space.

Strapped atop an United Launch Alliance Atlas V rocket, the X-37B space plane had a smooth ascent into space, quickly reaching Mach 1 -- the speed of sound -- as it traveled to its place in low Earth orbit.

While it is not known how long the plane's fourth mission will last, Wright-Patterson Air Force Base said last month the plane will be testing a Hall thruster, a type of propulsion system that could one day be used to power spacecraft on long-haul missions.

PHOTO: The U.S. Air Forces X37-B space plane launched today from Cape Canaveral in Florida. U.S. Air Force
The U.S. Air Force's X37-B space plane launched today from Cape Canaveral in Florida.

Measuring 29 feet in length and having a 15-foot wingspan, the unmanned re-usable orbital test vehicle looks like a miniature version of NASA's now retired space shuttles.

PHOTO: The U.S. Air Forces X37-B space plane launched today from Cape Canaveral in Florida. U.S. Air Force
The U.S. Air Force's X37-B space plane launched today from Cape Canaveral in Florida.

Like the space shuttle, the X-37B lands on runways, though it does so without pilots at the helm.

PHOTO: The U.S. Air Forces X37-B space plane launched today from Cape Canaveral in Florida. U.S. Air Force
The U.S. Air Force's X37-B space plane launched today from Cape Canaveral in Florida.

The plane touched down last October at Vandenberg Air Force Base in California, marking the end of its third mission and 674 consecutive days in space.

Comments