DARPA has released video footage of the Falcon HTV-2 flight earlier this month, which ended unceremoniously after just three minutes when it lost contact with the vehicle. And, guess what, DARPA says the flight was a great success.
On August 11, the HTV-2 separated from the Minotaur IV rocket at a sub-orbital altitude - and went silent, before plunging into the Pacific Ocean.
But, says DARPA, it did demonstrate stable aerodynamically controlled Mach 20 flight for nearly three minutes. Further, the Minotaur IV launch vehicle again successfully delivered the HTV-2 to its preprogrammed release point, at the appropriate velocity and orientation.
This involved safely and reliably performing a series of aggressive banks and turns.
DARPA's also released a blink-and-you'll-miss-it video of the Mach 20 flight, taken with a hand-held camera. "It gives us a visceral feel for what it means to fly at Mach 20,” says DARPA director Regina Dugan.
According to Air Force Major Chris Schulz, HTV-2 program manager, as much as 30 percent of the total test flight cost was spent on ways of collecting data.
"We’ve been working for more than 50 years to identify how to predict when the transition from laminar to turbulent flow will occur. This allows us to assess when a vehicle is about to experience its highest drag and heat load. Initial assessment of the data indicates that our pre-flight models successfully predicted transition to within ten seconds of actual transition point," says Dugan.
"If this information proves true upon further analysis, we’ll have a better understanding of overall system capability and flight dynamics — how far it can fly with more accuracy."