The U.S. Air Force's robotic X-37B space plane is now the longest in the clandestine program's history. The X-37B has spent 675 days on its latest Earth-circling mission, which is known as Orbital Test Vehicle-4 (OTV-4).
The space plane has broken the previous record of 674 days that was set during OTV-3. The mission started in December 2012 to October 2014.
It’s not yet clear how long the new record will last. Most X-37B activities and payloads are classified. The Air Force has historically been silent about the landing plans of the space plans.
Captain AnnMarie Annicelli, an Air Force spokeswoman said that the completion of the program's on-orbit demonstrations and objectives for the mission will determine the landing date of the space plane.
The OTV-4 is yet to meet the overall record for longest space mission. Some Earth-observation satellites have operated for decades.
Some of these satellites include Landsat-5 which has studied the planet from 1984 to 2013. The Voyager 1 and 2 probes are still sending data to earth, they were launched back in 1977.
It’s a known fact that the Air Force has two X-37B vehicles. Both were built by aerospace giant Boeing. The X-37B launches vertically and lands horizontally on a runway.
The X-37B looks like small version of the space shuttle. The solar-powered X-37B is just 29 feet (8.8 meters) long and 9.6 feet (2.9 m) tall, with a wingspan of about 15 feet (4.6 m).
The two X-37Bs have flown four space missions to date, each of which has set a new duration record. The OTV-1 launched on April 22, 2010, and landed on Dec. 3 of that year.
The OTV-1 spent a total of 224 days in orbit. The OTV-2 took off on March 5, 2011, and landed on June 16, 2012 a total of 468 days.
The OTV-3 launched on Dec. 11, 2012, and landed on Oct. 17, 2014 a total of 674 days. Finally, the OTV-4 lifted off on May 20, 2015.
The plane’s orbital lifetime is designed to be 270 days. Therefore, the latest three missions surpassed the expected lifetime.
Many have speculated that the X-37B may be a space weapon because of the secrecy surrounding the program. However, experts say the space plane does not seem big enough or maneuverable enough to be used to manipulate other satellites.
The Air Force has emphasized that the X-37B has two primary objectives: testing reusable spacecraft technologies, and helping to conduct experiments that can be returned to Earth for examination.
The four X-37B missions have launched from Florida's Cape Canaveral Air Force Station. The first three landed at Vandenberg Air Force Base in California.