"The greatest achievement from Flight Two, which the ERB's findings underscored, was that we successfully incorporated aerodynamic knowledge gained from the first flight into the second flight," said Air Force Maj. Chris Schulz, DARPA program manager, in a press release.
The first flight of the aircraft corrected engineers' models regarding the HTV-2's aerodynamic design, which allowed the aircraft to retain aerodynamic stability for the duration of the second flight, he said.
Data the ERB learned from the second flight will inform future design decisions about the properties of thermal protective material for maintaining an aircraft speed of Mach 20 inside the Earth's atmosphere, according to DARPA, which found that thermal modeling and ground testing were not enough to predict what protection the HTV-2 would need in actual flight.
This information "can now be used to adjust our assumptions based on actual flight data and modify our modeling and simulation to better characterize thermal uncertainties and determine how to assess integrated thermal systems," according to Schulz.
Going forward, DARPA will use the findings to achieve the goal of its Office of the Secretary of Defense, Acquisition, Technology & Logistics, Strategic Warfare directorate, which is to create an aircraft that can reach anywhere in the world in less than one hour.