The US Air Force’s (USAF) unmanned, reusable space plane X-37B orbital test vehicle mission 3 (OTV-3) has successfully landed at Vandenberg Air Force Base in California, US.
Launched aboard an Atlas V rocket from Cape Canaveral Air Force Station, Florida, in December 2012, the OTV-3 conducted on-orbit experiments for 674 days during its mission, extending the total number of days spent on-orbit for the OTV programme to 1367.
An unnamed X-37B programme manager said: "The landing of OTV-3 marks a hallmark event for the programme.
"The mission is our longest to date and we’re pleased with the incremental progress we’ve seen in our testing of the reusable space plane."
Built by Boeing Phantom Works, the X-37B is a derivative of the company’s X-40A space manoeuvre vehicle, and can operate at Mach 25 velocity range upon its re-entry.
Boeing Experimental Systems director Ken Torok said: "With a programme total of 1,367 days on orbit over three missions, these agile and powerful small space vehicles have completed more days on orbit than all 135 Space Shuttle missions combined, which total 1,334 days.
"The innovative X-37B combines the best of an aircraft and a spacecraft into an affordable, responsive unmanned vehicle and continues to demonstrate that reusable space vehicles are affordable options that support vital missions."
Managed by the Air Force Rapid Capabilities Office, the X-37B programme performs space experimentation, risk reduction and concept-of-operations development for reusable space vehicle technologies that could become key enablers for future space missions.
The programme’s first mission, OTV-1, was launched in April 2010 and it for lasted 225 days, while the second X-37B space plane spent 469 days in orbit following its launch in March 2011.
The USAF is preparing to launch the fourth X-37B mission from Cape Canaveral Air Force Station in 2015.
Image: USAF recovery crew members process the X-37B Orbital Test Vehicle after its landing at Vandenberg Air Force Base in California, US. Photo: courtesy of Boeing.