The U.S. Air Force space plane X-37B is set to return to Earth on Tuesday, after spending 22 months in orbit for a unique mission that some have called covert.
The officials in the Vandenberg Air Force Base in California have been preparing for its landing since Friday. The exact arrival time is uncertain because the vehicle is flying autonomously and weather, along with technical conditions, may cause a delay, Reuters reported. The Air Force is expecting the vehicle from 8 a.m. to 5 p.m. PT Tuesday.
"Team Vandenberg stands ready to implement safe landing operations for the X-37B Orbital Test Vehicle, the third time for this unique mission" said Col. Keith Baits, 30th Space Wing commander.
The Air Force sent out two X-37B Orbital Test Vehicles (OTVs) since 2010 for missions that are not yet revealed to the public. The OTV returning on Oct. 14 was deployed in December 11, 2012 aboard an unmanned Atlas 5 rocket from Cape Canaveral Air Force Station in Florida.
But according to the Air Force, there was no secret mission happening; the space plane was developed to demonstrate reusable unmanned spacecraft technologies to fly and return experiments to Earth.
"Technologies being tested in the program include advanced guidance, navigation and control, thermal protection systems, avionics, high temperature structures and seals, conformal reusable insulation, lightweight electromechanical flight systems, and autonomous orbital flight, re-entry and landing," the Air Force said.
Some speculations surfaced after the space plane spent longer than its nine-month mission, including testing secret weapons or surveillance activities, according to CNN. The officials plan to carry out more missions for their objectives.
It is expected that the X-37B vehicle will be moved to the newly-leased space hangars that the Air Force recently secured. The military decided to relocate the X-37B mission to Florida to reduce operation costs. Renovations of the two space shuttle hangars are ongoing and expected to be completed by end of the year.
