C4ISR

Air Force's unmanned 'shuttle' breaks orbital endurance record

The Air Force’s secretive X-37B space plane surpassed its previous space endurance record as it continues stay in lower earth orbit. The current unmanned space mission has lasted 471 days, as of March 28, and counting.

Launched on Dec. 11, 2012, the unmanned space shuttle surpassed its previous record on Mar. 26 while conducting the Orbital Test Vehicle 3 (OTV-3) mission, the third flight of the space program. The previous record of 469 days was set by OTV-2, which was launched in 2011.

The X-37B is designed to explore the use of a reusable space vehicle in support of long-term space objectives. The program was originally funded by Boeing, NASA, and the Defense Advanced Research Projects Agency, and was transferred to the Air Force in 2004.

The OTV-2 lands in 2012 after 469 days in orbit.


Resembling the now-retired Space Shuttle, the X-37B utilizes the same lifting-body design. At about one-fourth of the size of the original shuttle, the spacecraft has a small payload bay that measures seven feet long by four feet wide. However, it has been upgraded with lighter composite structures, a new generation of high-temperature wing leading-edge tiles, and more durable heat-resistant tiles. Additionally, the design eschews the use of hydraulics – all flight controls and brakes use electromechanical actuation.

All avionics on the spacecraft are designed to make de-orbiting and landing functions autonomous. In both the OTV-1 and OTV-2 flights, the X-37B returned to Earth on autopilot, reports Huffington Post.

The OTV missions are classified and have sparked speculation among amateur satellite trackers and military enthusiasts as they continue to keep an eye out for the X-37B. The spacecraft is designed to be “highly flexible and maneuverable” according to Boeing.

It has been widely speculated that the X-37B could be carrying intelligence or scientific payloads as a test vehicle for new space-based surveillance technologies. Comments by the Air Force to the Christian Science Monitor have mentioned the transportation of “satellite sensors, subsystems, components, and associated technology” into space. The spacecraft’s missions have also been carried out under the Air Force Rapid Capabilities Office, which is rumored to have close ties to the intelligence community, according to Computerworld UK.

In any case, the Air Force will have plenty of data on hand for examining in-flight capabilities and the long-term effects on system components and future payloads as the X-37B continues to spend time in space.

About the Author

Joey Cheng is an editorial fellow with Defense Systems.

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