An unexpected degree of aeroshell degradation was "the most probable cause" of the premature flight termination of DARPA's Hypersonic Technology Vehicle during a flight over the Pacific Ocean in August 2011, according to the findings of the agency's independent engineering review board, released on April 20, 2012. This was a second flight of an experimental, expendable HTV-2 vehicle. It built upon the lessons of the first HTV-2 test flight in April 2010. Here, an artist's rendering of an HTV-2 in flight.
DARPA illustration
