It features unique design of 132 coaxial injection elements causing swirl mixing of the MMH propellants with nitrogen tetroxide oxidizer.

Hypergolic propellants spontaneously ignite on contact expanding to supersonic velocities and escaping through cooled nozzle extension.

Ignition qualification programme preparing engine for handling new Automated Transfer Vehicle that requires 3 ignitions per flight was completed in 2007 and flew with Jules Verne ATV on Ariane 5 flight 528.

Aestus II (also known as RS-72) was a turbopump-fed version of the pressure-fed Aestus developed in a collaboration between the Ottobrunn Space Propulsion Centre and Pratt & Whitney Rocketdyne (Boeing Rocketdyne at the time).

Aestus II development was supported by Pratt & Whitney Rocketdyne which provided turbopump for the engine.