HTV-2 Flight Anomaly Explained

An independent review board has concluded that “higher-than-predicted yaw, which coupled into roll” is the most likely reason why the inaugural flight of DARPA’s hypersonic technology vehicle (HTV-2) was cut short back in April. The roll rate eventually reached a threshold where the vehicle’s autonomous flight system terminated the flight, stated the agency’s release on the board’s findings. Armed with these findings, DARPA is marching forward towards the next flight of an HTV-2 vehicle next year. “No major changes to the vehicle or software are required to mitigate the first flight anomaly,” said David Neyland, DARPA’s Tactical Technology Office director. He said engineers “will adjust the vehicle’s center of gravity, decrease the angle of attack flown, and use the onboard reaction control system to augment the vehicle flaps when HTV-2 flies next summer.” (See also Washington Times report)