dtmos writes "DARPA has announced that its Falcon Hypersonic Technology Vehicle 2 flight on Thursday, 11 August, 'experienced a flight anomaly post perigee and into the vehicle's climb. The anomaly prompted the vehicle's autonomous flight safety system to use the craft's aerodynamic systems to make a controlled descent and splash down into the ocean.' 'According to a preliminary review of the data collected prior to the anomaly encountered by the HTV-2 during its second test flight,' said DARPA Director Regina Dugan, 'HTV-2 demonstrated stable aerodynamically controlled Mach 20 hypersonic flight for approximately three minutes. It appears that the engineering changes put into place following the vehicle's first flight test in April 2010 were effective. We do not yet know the cause of the anomaly for Flight 2.'"