A US Air Force X-37B unmanned space plane was launched on its second mission today. The vehicle was sent into low-earth orbit from Cape Canaveral Air Force Station Launch Complex 41 atop an Atlas V rocket at 1:03 p.m. EST (1803 GMT). This mission, designated OTV-3, is the first time an X-37B has returned to orbit.

The 29-foot long (8.8 m) Boeing-built X-37B was first launched in April 2010 and returned to Earth in December of that year after a mission lasting over 220 days and became the first unmanned spacecraft to land on a runway autonomously. This year, its sister vehicle set the orbital duration record for a reusable space vehicle when it landed after 469 days in space.

As with the previous two X-37B flights, the US Air Force is not forthcoming about details the payload, mission or flight duration of the classified spacecraft. However, Paul Rusnock, vice president of Boeing Government Space Systems, said, "The second mission for [X-37B] demonstrates the vehicle is capable of multiple missions and affordable access to space."

Source: Boeing