Secret Air Force X-37B Space Plane

By James Donahue

When its 15-month-long test flight in space recently came to a successful conclusion, the Air Force’s X-37B space plane drew only brief media attention when it landed at California’s Vandenberg Air Base. But what is this strange craft and what is its purpose?

What we know about the X-37B is that it is an orbital test vehicle built by Boeing’s Phantom Works. It has been described as a reusable spacecraft that operates like a miniature space shuttle and is remotely controlled from the ground. It was launched on its secret mission on March 5, 2011, using an Atlas 5 rocket to send it into orbit from the Cape Canaveral Air Force Station in Florida.

This was the second aircraft of this type constructed by Boeing, and the second extended flight of its kind. The first test flight that occurred in 2010 lasted 225 days. A third flight is planned for liftoff sometime this fall.

These mystery planes measure only about 29 feet in length and are 15 feet wide. They have a payload bay about the size of a pickup truck bed. They are equipped with a deployable solar array power system.

While the Air Force is remaining tight lipped about the X-37B, Arthur Grantz, chief engineer in the Experimental Systems Group at Boeing Space suggested in a recent interview that he had a vision for this type of spacecraft to carry astronauts and cargo to and from the International Space Station and elsewhere in space.

The concept began as a NASA project but was turned over to the Air Force in 2004 as funding for NASA began to dry up. The original plan, according to Wikipedia, was to carry the craft into orbit in the cargo bay of the Space Shuttles. The thought was that the X-37 could rendezvous with satellites to refuel them, replace failed solar arrays using a robotic arm and support Space Control defense systems.

NASA once announced that the development of the X-37 would "aid in the design and development of a full-sized Orbital Space Plane capable of carrying crew to and from the Space Station, thus replacing the retired shuttles.

Once it rides the rocket into orbit, the X-37 is independently powered by an Aerojet engine that uses storable propellants. According to an article in Air & Space Magazine, the craft is powered in space by Gallium Arsenide solar cells and lithium-ion batteries.