Darpa Hypersonic Glider: The Pentagon has explained why it aborted the DARPA hypersonic glider last year. Apparently, the unmanned craft's skin started to peel off as it reached speeds of Mach 20.
An unmanned hypersonic glider likely aborted its 13,000 mph (20,920 kph) flight over the Pacific Ocean last summer because unexpectedly large sections of its skin peeled off, the U.S. Defense Advanced Research Projects Agency said Friday.
The Hypersonic Technology Vehicle-2, launched from Vandenberg Air Force Base, California, atop a rocket and released on Aug. 11, 2011, was part of research aimed at developing super-fast global strike capability for the Department of Defense.
The vehicle demonstrated stable aerodynamically controlled flight at speeds up to 20 times the speed of sound, or Mach 20, for three minutes before a series of upsets caused its autonomous flight safety system to bring it down in the ocean, DARPA said in a statement.
A gradual wearing away of the vehicle's skin was expected because of extremely high temperatures, but an independent engineering review board concluded that the most probable cause was "unexpected aeroshell degradation, creating multiple upsets of increasing severity that ultimately activated the Flight Safety System," the statement said.