Aerojet Rocketdyne [AJRD] said on July 21 that it has finished a second series of propulsion system tests under the Defense Advanced Research Projects Agency’s (DARPA) Operational Fires (OpFires) program to develop a ground-launched hypersonic missile for tactical use.

“During the propulsion tests, called cold gas testing, the test articles operated successfully with all components providing critical data to the operation of the OpFires propulsion system,” Aeroject Rocketdyne said in a statement. “The test series followed last year’s successful subscale propulsion test firings.”

Hypersonic is a top DoD research and development effort. James Faist, the director of Defense Research and Engineering for Advanced Capabilities (DDR&E AC), has established a Joint Hypersonics Transition Office (JHTO) with $100 million in funding. Congressional appropriators funded the office “to develop and implement an integrated science and technology roadmap for hypersonics and to establish a university consortium for hypersonics research and workforce development.”

The U.S. Army said last year that it plans to field a hypersonic weapon in fiscal 2023.

“DARPA’s OpFires program aims to develop a two-stage missile capable of engaging high-value, time-sensitive targets from standoff range in contested environments,” Aerojet Rocketdyne said on July 21. “The effort to date has advanced the technology for an upper stage featuring a tunable propulsion system, according to DARPA.”

The company said that it has deep experience in hypersonics, including scramjets, solid rocket motor boosters, warheads and missile defense, and that the company has been supporting DARPA’s OpFires program “through a Phase 1 contract to design propulsion concepts and technologies.”

“The contract continued with an $8.8 million option for Phase 2 of the program, which is expected to culminate in late 2020 following multiple test firings,” Aerojet Rocketdyne said.