Rutherford (rocket engine)

Rutherford is named after renowned New Zealand-born scientist Ernest Rutherford. It is a small liquid-propellant rocket engine designed to be simple and cheap to produce. It is used as both a first-stage and a second-stage engine, which simplifies logistics and improves economies of scale.[6][7] To reduce its cost, it uses the electric-pump feed cycle, being the first flight-ready engine of such type.[5] It is fabricated largely by 3D printing, using a method called electron-beam melting. Its combustion chamber, injectors, pumps, and main propellant valves are all 3D-printed.[14][15][16]

As with all pump-fed engines, the Rutherford uses a rotodynamic pump to increase the pressure from the tanks to that needed by the combustion chamber.[5] The use of a pump avoids the need for heavy tanks capable of holding high pressures and the high amounts of inert gas needed to keep the tanks pressurized during flight.[17]

The pumps (one for the fuel and one for the oxidizer) in electric-pump feed engines are driven by an electric motor.[17] The Rutherford engine uses dual brushless DC electric motors and a lithium polymer battery. It is claimed that this improves efficiency from the 50% of a typical gas-generator cycle to 95%.[18] However, the battery pack increases the weight of the complete engine and presents an energy conversion issue.[17]

Each engine has two small motors that generate 37 kW (50 hp) while spinning at 40 000 rpm.[18] The first-stage battery, which has to power the pumps of nine engines simultaneously, can provide over 1 MW (1,300 hp) of electric power.[19]

The engine is regeneratively cooled, meaning that before injection some of the cold RP-1 is passed through cooling channels embedded in the combustion chamber and nozzle structure, transferring heat away from them, before finally being injected into the combustion chamber.

• Curie (rocket engine)
• TEPREL
• Merlin (rocket engine family)

• Rocket Lab Propulsion Section