On this day in 2011, the Falcon Hypersonic Technology Vehicle, the fastest plane ever built, blasted off from California’s Vandenberg Air Force Base. After hurling through space at 21,000 kilometres per hour, the unmanned plane was lost to researchers after only nine minutes. It hasn’t been seen since.
The Hypersonic Technology Vehicle is a crewless, experimental rocket glider that was developed as part of a joint project between the Defense Advanced Research Projects Agency (DARPA) and the United States Air Force. It was developed as part of Prompt Global Strike, a US military effort to pioneer a system that can deliver a precision conventional weapon strike anywhere in the world within one hour. As such, the Falcon can move at 21,000 kilometres per hour or 5.8 kilometres per second—that’s 20 times the speed of sound. Though exact specifications of the Hypersonic Technology Vehicle are not known for security purposes, the arrow-headed, aerodynamic craft is made of durable carbon composite material. Built by Lockheed Martin, the craft is lightweight, has a high lift to drag ratio, and automatic navigation control.
The Falcon’s maiden voyage launched on 22 April 2010 and the craft was to fly 7,700 kilometres across the Pacific From California to Kwajalein in the Marshall Islands. Nine minutes into the flight, however, contact was lost and the flight was terminated remotely. Researchers believe the searing high speeds caused portions of the craft’s skin to peel from its aerostructure and resulting gaps created strong shock waves around the vehicle, causing it to roll abruptly.
A second voyage took place 11 August 2011. The unmanned craft successfully launched from Vandenberg Air Force Base near Santa Barbara, California, separated from its Minotaur IV Lite rocket booster, and entered glide phase, but again lost contact with control about nine minutes into the flight. Monitoring stations were positioned along the craft’s flight path, but none could detect the lightning-fast craft. The unmanned craft has not been seen since, though researchers believe it terminated itself somewhere over the Pacific Ocean as a safety precaution.
Those two voyages may have been among the most expensive flights ever: Two test runs of the Falcon cost $308 US million and estimates for developing a fully functional glider have run as high as $10 US billion.