The U.S. Air Force has rescheduled the second flight of the Defense Advanced Research Projects Agency’s Hypersonic Technology Vehicle 2 (HTV-2) to tomorrow after unfavorable weather forced today’s attempt to be scrubbed.
The flight was originally scheduled from Space Launch Complex 8 at Vandenberg AFB, Calif., at 7 a.m. As launch time approached for the Lockheed Martin-built hypersonic glider, Darpa said the countdown was holding at 70 min. due to weather constraints. This was held until around 8 a.m. PDT, at which point the launch was finally scrubbed. Tomorrow’s attempt will see the Minotaur IV-boosted HTV-2 fly a planned route covering 4,100 nm across the Pacific in 30 min. The splash-down point is off Kwajalein Atoll.
The HTV-2 is designed to demonstrate the high lift-to-drag aerodynamics and high-temperature materials needed for sustained hypersonic flight, with the goal of validating technology for a vehicle able to reach anywhere in the world in 60 min.
The second HTV-2 incorporates a more robust flight control system to counter the issues that led to the loss of the first vehicle 9 min. into the flight on April 22, 2010. The revised control system incorporates changes to the center of gravity to reduce the lateral/directional coupling that occurred on the first flight, as well as adaptations to allow the vehicle’s nitrogen-gas reaction control system to be used for yaw control both in the atmosphere and in space.
The Air Force says the launch will be the fourth of Orbital Sciences Corp.'s Minotaur IV, which uses decommissioned Peacekeeper intercontinental ballistic missile motors. It will also be the ninth launch for the Minotaur program from Vandenberg AFB.
The HTV-2 is the final surviving element of Darpa’s Falcon program to demonstrate technology for a prompt global strike system. The program will terminate with the second launch.