The US Air Force's experimental X-37B space plane is off on its travels again, blasting off from Cape Canaveral yesterday atop an Atlas V rocket.
The X-37B, known as OTV-1, is a smaller, unmanned version of the Space Shuttle, measuring 29 feet long and 15 feet wide. It launches into orbit on a conventional rocket but, like the shuttle, lands on a runway like a plane.
"This is a unique spacecraft, since it is the first to launch on an Atlas V, return to Earth landing at Vandenberg Air Force Base in California and then fly again on this mission," says Jim Sponnick, vice president of operations for launch specialist United Launch Alliance.
Built by Boeing, the six-ton craft's official mission is to try out technologies for a reusable, unmanned space platform, and to carry out unspecified experiments. Many have questioned what those might be, however, suggesting instead that the vehicle is intended for spying or even as a weapons platform.
"The second mission for OTV-1 demonstrates the vehicle is capable of multiple missions and affordable access to space," says Paul Rusnock, vice president of Boeing Government Space Systems.
OTV-1, the first of two vehicles in the program, took its first spin in 2010 on an eight-month flight.
A second vehicle, OTV-2, set a record for a reusable space vehicle in June this year when it completed a 469-day mission.
Yesterday's launch was delayed by two months due to a technical problem with the Delta 4 rocket's RL-10B-2 upper stage engine.