27, 2019 at NASA's Shuttle Landing Facility, marking the second time an X-27B has done so. It also carried several other experiments and small satellites, Air Force officials said. The mission lasted 780 days (another record) carried the Air Force Research Laboratory Advanced Structurally Embedded Thermal Spreader, an experiment designed to 'test experimental electronics and oscillating heat pipe technologies in the long-duration space environment,' according to an Air Force statement. 7, 2017 on SpaceX's Falcon 9 rocket, lifting off from the historic Launch Complex 39A at NASA's Kennedy Space Center (KSC) in Florida. The three previous missions landed at Vandenberg Air Force Base. It was the first X-37B landing at NASA's Shuttle Landing Facility at the Kennedy Space Center in Cape Canaveral, Florida. After 718 days in space, the OTV-4 mission ended with a smooth runway landing on May 7, 2017. OTV-4 began on May 20, 2015, and broke OTV-3's duration record on March 25, 2017.

The OTV-4 mission marked the second flight for the X-37B that flew OTV-2. OTV-3, which uses the same vehicle that flew the OTV-1 mission, began on Dec. OTV-2 stayed in space for more than twice as long, launching in March 2011 and returning to Earth 468 days later, in June 2012. OTV-1 blasted off in April 2010 and stayed aloft for 224 days. The fifth launched in September 2017 on a SpaceX Falcon 9 rocket. Four flights have reached space with the help of United Launch Alliance's Atlas V rocket. Two different X-37B vehicles have flown a total of five missions, which are known as OTV-1, OTV-2, OTV-3 and OTV-4 (short for Orbital Test Vehicle). The space planes are built by Boeing's Phantom Works division. The X-37B program is now run by the Air Force's Rapid Capabilities Office, with mission control for orbital flights based at the 3rd Space Experimentation Squadron at Schriever Air Force Base in Colorado. NASA's envisioned Orbital Vehicle was never built, but it served as the inspiration for the space plane that came to be called the X-37B. At that point, X-37 became a classified project.ĭARPA finished the ALTV part of the program in 2006, conducting a series of captive-carry and free-flight tests. military in 2004 - specifically, the Defense Advanced Research Projects Agency (DARPA).

The X-37 program started in 1999 with NASA, which initially planned to construct two vehicles: an Approach and Landing Test Vehicle (ALTV) and an Orbital Vehicle.

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