Air Force X-37B returned to Earth over the weekend

The United States Air Force has announced that early the morning of June 16 its unmanned, reusable space plane called the X-37B Orbital Test Vehicle landed after spending 469 days in orbit. The Air Force says that the vehicle spent its time in orbit conducting onboard experiments and its primary mission of checking out the vehicle itself. This is one of two space vehicles the Air Force operates.

The X-37B is the longest space mission behind the NASA Discovery shuttle program. The spacecraft is designed to perform risk reduction, experimentation, and concept of operations development for reusable space technologies according to the Air Force.

The X-37B program was originally a NASA initiative and was later transferred to DARPA in 2004. The spacecraft first launched in 2006. The space vehicle weighs 11,000 pounds and is about one-fourth the size of the space shuttle. The spacecraft was designed to take experiments into orbit and return them safely.

"The vehicle was designed for a mission duration of about 270 days," said Lt. Col. Tom McIntyre, the X-37B program manager. "We knew from post-flight assessments from the first mission that OTV-1 could have stayed in orbit longer. So one of the goals of this mission was to see how much farther we could push the on-orbit duration."