Photos: Air Force's 2nd Secretive X-37B Space Plane Flight

X-37B in Space

The U.S. Air Force's X-37B (shown here in an illustration) is an unpiloted military space plane capable of long-duration flights in Earth orbit. The robotic spacecraft has a solar array for power and a payload bay the size of a pickup truck bed.

It's An Orange-y Sky

Early artist concept of the X-37 advanced technology flight demonstrator re-entering Earth’s atmosphere. The X-37 was billed by NASA as a testbed for dozens of advanced structural, propulsion and operational technologies that could dramatically lower the

Weather Delay

An Atlas 5 rocket holding a U.S. Air Force X-37B space plane in its nose cone sits on the launch pad in Floriday on Friday, March 4, 2011. Bad weather delayed the launch, with another attempt coming March 5.

X-37B: Let's Work

This NASA Marshall Space Flight Center image shows on-orbit functions for the reusable X-37B space plane, now under the wing of the U.S. Air Force.

Robotic Space Plane Rises Again

A United Launch Alliance Atlas 5 rocket carrying the Air Force's second X-37B robot space plane, the Orbital Test Vehicle 2 (OTV-2), launches from its Space Launch Complex-41 at Florida's Cape Canaveral Air Force Station on March 5, 2011 at 5:46 p.m. EST.

Mystery Mission Begins for OTV-2

The Air Force's second X-37B robot space plane blasts off from Cape Canaveral Air Force Station in Florida on March 5, 2011 to begin its secret Orbital Test Vehicle 2 mission.

Do I Have to Draw a Diagram?

This exploded view details the components of the Atlas V 501 vehcle. The configuration consists of a single Atlas V booster stage and the Centaur upper stage, with the OTV mission encapsulated within the payload fairing.

All Stacked Up

The U.S. Air Force’s X-37B space plane prototype, called the Orbital Test Vehicle 1, is primed for its debut launch into space in April 2010.

Home Again

Despite its robotic nature, the X-37B space plane received a warm welcome from Air Force crews at Vandenberg. Here, the vehicle appears to be undergoing safing procedures after landing on Dec. 3 at 1:16 a.m. PST (0916 GMT). Significant weathering, or discoloration, can be seen on the spacecraft's upper thermal blanket insulation.

X-37B Transferring Cargo at the ISS

This series of illustrations depicts the sequence of events for a potential X-37B space plane delivery flight to the International Space Station. The Boeing-built X-37B is a robotic space plane currently flying classified missions for the U.S. Air Force.