An experimental missile powered by a supersonic combustion ramjet inadvertently separated from a Boeing B-52 carrier aircraft and was destroyed, according to a report.
The scramjet missile, which was developed under the joint Defense Advanced Research Projects Agency and the US Air Force Hypersonic Air-breathing Weapon Concept program, was destroyed during a recent captive-carry test, sources told Aviation Week.
Scramjets allow missiles to reach hypersonic speeds that greatly exceed the speed of sound, often reaching Mach 5 and above.
The cause of the accident, which is believed to have involved an aircraft from the 419th Flight Test Squadron at Edwards Air Force Base in California, remains under investigation, the news outlet reported.
The Air Force referred Aviation Week to DARPA, but the Department of Defense agency declined to provide any details.
“Details of those flight demonstrations are classified,” a DARPA spokesman told the outlet.
The payload may have detached from the B-52 in flight over land — possibly over a test range such as the Edwards Precision Impact Range Area or the nearby Naval Air Weapons Station test range at China Lake, according to Aviation Week.
The HAWC program is already several months behind an original schedule that called for a first flight last year, the outlet reported.
In 2017, DARPA chose Lockheed Martin to develop a HAWC demonstrator powered by an Aerojet Rocketdyne scramjet after it turned down another design submitted by Raytheon.
But a redesigned Raytheon missile impressed DARPA, leading to a contract being awarded for a second flight test in March 2019.
The contract to develop the prototype was at a cost of $174.7 million, according to Defense.info.