Artist's illustration of the U.S. Air Force's X-37B space plane in orbit. The vehicle's latest
mission marked 675 days in space on March 25, 2017, setting a new duration record for the X-37B program.
Credit: NASA Marshall Space Flight Center
The ongoing mission of the U.S. Air Force's robotic X-37B space plane is now the longest in the clandestine program's history.
As of today (March 25), the X-37B has spent 675 days on its latest Earth-circling mission, which is known as Orbital Test Vehicle-4 (OTV-4). The previous record was 674 days, set during OTV-3, which lasted from December 2012 to October 2014.
It's unclear what the new duration record will end up being; most X-37B activities and payloads are classified, and the Air Force has historically been tight-lipped about landing plans. [The X-37B's Fourth Mystery Mission in Photos] https://www.livescience.com/58415-x-37b-space-plane-breaks-orbital-record.html
