Aerojet Rocketdyne has completed hot-fire tests on the US Air Force’s (USAF) sub-scale, oxygen-rich pre-burner for its hydrocarbon boost technology demonstrator (HBTD) programme.

The sub-scale tests will aid design and development of the full-scale pre-burner and HBTD engine.

A pre-burner plays a key role in the oxygen-rich staged combustion (ORSC) cycle, which provides high thrust-to-weight and performance irrespective of fuel type.

"These technologies will be further advanced to support the next-generation of expendable launch systems."

Aerojet Rocketdyne HBTD programme manager Joe Burnett said: "Throughout the sub-scale fabrication and facility checkouts, we’ve documented a number of lessons learned that have directly influenced the full-scale pre-burner design.

"We are looking forward to what more we will learn during the hot-fire test series."

The company will evaluate multiple injector configurations to design a high-performance, reliable, liquid oxygen / kerosene rocket engine.

Designed as a re-usable system, the engine uses liquid oxygen and liquid kerosene (RP-2) to generate 250,000lb of thrust. It can power up to 100 flights supported by its long-life technologies and advanced materials.

The engine will incorporate burn-resistant alloys manufactured under Metals Affordability Initiative with the USAF.

These technologies will be further advanced to support the next-generation of expendable launch systems, as well as rapid turn-around usability for future re-usable launch systems.

USAF’s advanced liquid rocket engine stability tools programme (ALREST) will use the test results to advance its capabilities in combustion stability modelling.