The Boeing X-37B, a highly classified robotic spacecraft built for the US Air Force, is to make its third landing after spending more than 670 days in low-Earth orbit. The space plane’s purpose remains a mystery, though surveillance is a likely candidate.
X-37B is expected to land automatically at Vandenberg Air Force Base in California, a facility serving as a testing base for the DoD.
“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.
While the base officials say the exact date and timing of the landing would depend on weather conditions, the base issued a notice to aviators to stay away from the area between 3 am and 4 pm. Tuesday, local time (10 am to 11 pm GMT).
The spacecraft was launched on December 11, 2012 by an Atlas V rocket from Cape Canaveral Air Force Station. It has since been flying in low-Earth orbit, performing whatever mission the Pentagon had prepared for its third test run.
In March, X-37B broke its own space longevity record for staying in orbit. Its two previous rounds in space in 2010 and 2011-2012 lasted 225 and 469 days, respectively.
The reusable spacecraft, which resembles an unmanned version of the now decommissioned Space Shuttle vehicles, remains highly classified. The secrecy shrouding X-37B led to a plethora of versions about its purpose.