Aerojet Rocketdyne successfully completed two hot-fire tests of a rocket motor designed to boost an air-launched tactical glide hypersonic vehicle during its initial phase of flight.

The tests, which were done under simulated extreme cold and hot conditions, took place on an undisclosed “recent” date at the Air Force Research Laboratory (AFRL) at Edwards AFB in California, Aerojet Rocketdyne said.

The motors were tested at extreme temperatures to verify they would perform as expected across the full range of anticipated operational conditions, the company says.

In a boost glide hypersonic system, a rocket accelerates its payload to high speeds; the payload then separates from the rocket and glides unpowered to its destination at hypersonic speeds up to Mach 20. Lockheed Martin is leading the development of the USAF’s boost glide programme, called the Air-launched Rapid Response Weapon (ARRW), and Aerojet Rocketdyne is subcontracted to supply the booster rockets.

Aerojet Rocketdyne rocket booster test for hyperso

"These ground hot-fire tests demonstrate the robustness of our motor technology to enable the next generation of air-launched boosters,” said Aerojet Rocketdyne CEO and President Eileen Drake. “Data from these tests will be used to confirm our ballistic, thermal, structural and ignition models as we develop the next generation operational booster rocket motor.”

The USAF’s other hypersonic programme is an air-breathing, ram-jet-powered cruise missile called the Hypersonic Conventional Strike Weapon (HCSW) and is also being developed by Lockheed Martin. According to USAF specifications, the hypersonic cruise missile must be capable of being carried on fighter and bomber aircraft and have precision strike capability against high-value, time-critical fixed and relocatable surface targets in a single or multi-theater challenged environment.

The USAF is accelerating its efforts to develop hypersonic weapons and aircraft in light of advances and investments made in hypersonic technology by China and Russia. Recently, China conducted the maiden flight of a new hypersonic test vehicle, claiming the aircraft reached speeds of Mach 5.5 for more than six minutes and also topped out at Mach 6, according to a report by government mouthpiece China Daily on 6 August.

The difficulty in defending against hypersonic weapons has pushed the Pentagon into an arms race. Developing hypersonic weapons is the “highest technical priority” for the US military, said Michael Griffin, undersecretary of defense for research and engineering, in March 2018.