A report indicting the cause of problems for an advanced super-sonic glider was released and points to structural failure as the cause.
The United States Defense Advanced Research Projects Agency said on Friday that the unmanned hypersonic glider probably self-aborted during its 13,000 mph test flight over the Pacific Ocean last summer.
The agency explained that it was likely due to a structural failure of the outer shell of the aircraft that caused the existing safety measures to activate, destroying the glider in flight.
The glider, called the Hypersonic Technology Vehicle-2, left for its test flight from Vandenberg Air Force Base in California attached to a rocket to get it into low-Earth orbit last August.
The glider is part of a research program tasked with developing a supersonic global strike capability for the military.
The report indicated that the glider was aerodynamically stable considering that it reached speeds that were 20 times the speed of sound for approximately three minutes. Afterwards, though, part of the outer shell began to peel away, which activated the flight safety system.
Researchers were aware that there would be some damage to the outer casing given the extremely high temperatures the aircraft experienced caused by air friction.
An independent engineering review board concluded that the glider's destruction was likely due to "unexpected aeroshell degradation, creating multiple upsets of increasing severity that ultimately activated the Flight Safety System," the statement said.
Even though the glider crashed and was not recovered, data from that flight will be used to make modifications for the next series of tests, according to DARPA program manager Air Force Major Chris Schulz.
"The result of these findings is a profound advancement in understanding the areas we need to focus on to advance aerothermal structures for future hypersonic vehicles. Only actual flight data could have revealed this to us," he said.