The US Defense Advanced Research Projects Agency (DARPA) prematurely lost contact with the hypersonic test vehicle (HTV-2) on its second and final flight.
After a 24h delay due to inclement weather, the Orbital Sciences Minotaur IV rocket lifted off from Vandenberg AFB, California, lifting HTV-2 above the atmosphere.
DARPA confirmed successful separation from the launcher, telemetry data reception and entry into the high-speed glide phase. It then posted a notification on its official Twitter feed that ground stations had lost telemetry feed from HTV-2.
During the first flight of HTV-2, on 23 April, 2010, telemetry was lost 9min into the flight. A subsequent investigation found that the vehicle encountered unexpected yaw, followed by an uncontrollable roll. The onboard computer proceeded to steer the vehicle into the ocean.
The premature loss of HTV-2 marks the second major hypersonic loss of 2011; the June flight of the Boeing X-51 waverider failed when its scramjet encountered an inlet unstart upon startup.