RFA's Helix engine stands among the world's most advanced engine types, featuring a staged combustion system. Unlike conventional engines that use open combustion cycles, the Helix engine employs an oxygen-rich preburner to channel exhaust gases into the main combustion chamber, thus driving the turbopump for enhanced fuel burn. This staged combustion process raises Helix's efficiency by 7%, boosting RFA ONE micro launcher's payload capacity by 30%. Additionally, the Helix engine produces significantly fewer highly sooty exhaust gases than traditional engines, making it more eco-friendly.

The Helix engine employs RP-1 as propellant and liquid oxygen as an oxidizer, generating a thrust of 100kN and an Isp of 325s (SL) / 350s (Vac). The first stage of the rocket employs nine Helix engines, while the second stage uses a vacuum-optimized Helix engine.

The Helix(vac) is a vacuum-optimized version of the Helix Engine. RFA's Helix engine stands among the world's most advanced engine types, featuring a staged combustion system. Unlike conventional engines that use open combustion cycles, the Helix engine employs an oxygen-rich preburner to channel exhaust gases into the main combustion chamber, thus driving the turbopump for enhanced fuel burn. This staged combustion process raises Helix's efficiency by 7%, boosting RFA ONE micro launcher's payload capacity by 30%. Additionally, the Helix engine produces significantly fewer highly sooty exhaust gases than traditional engines, making it more eco-friendly.

The Helix engine employs RP-1 as propellant and liquid oxygen as an oxidizer, generating a thrust of 100kN and an Isp of 325s (SL) / 350s (Vac). The first stage of the rocket employs nine Helix engines, while the second stage uses a vacuum-optimized Helix engine.