 Sea-level Rutherford engine | |
| Country of origin |  United States New Zealand |
|---|---|
| Designer | Rocket Lab |
| Manufacturer | Rocket Lab |
| Application | First- and second-stage |
| Status | Active |
| Liquid-fuel engine | |
| Propellant | LOX /RP-1 |
| Cycle | Electric-pump-fed |
| Pumps | 2 |
| Configuration | |
| Chamber | 1 |
| Performance | |
| Thrust, vacuum |
|
| Thrust, sea-level |
|
| Thrust-to-weight ratio | 72.8 |
| Specific impulse, vacuum | 343 s (3.36 km/s) |
| Specific impulse, sea-level | 311 s (3.05 km/s) |
| Dimensions | |
| Diameter | .25 m (9.8 in) |
| Dry mass | 35 kg (77 lb) |
| Used in | |
| Electron, HASTE | |
| References | |
| References | [1][2][3][4][5][6][7] |
Rutherford is aliquid-propellant rocket engine designed by aerospace companyRocket Lab[8] and manufactured inLong Beach,California.[9] The engine is used on the company's own rocket,Electron. It usesLOX (liquid oxygen) andRP-1 (refined kerosene) as its propellants and is the first flight-ready engine to use theelectric-pump-fed cycle. The rocket uses a similar engine arrangement to theFalcon 9; a two-stage rocket using a cluster of nine identical engines on the first stage, and one vacuum-optimized version with a longer nozzle on the second stage. This arrangement is also known as anoctaweb.[10][5][6] The sea-level version produces 24.9 kN (5,600 lbf) of thrust and has aspecific impulse of 311 s (3.05 km/s), while the vacuum optimized-version produces 25.8 kN (5,800 lbf) of thrust and has a specific impulse of 343 s (3.36 km/s).[11]
First test-firing took place in 2013.[12] The engine was qualified for flight in March 2016[13] and had its first flight on 25 May 2017.[14] As of April 2024, the engine has powered 47 Electron flights in total, making the count of flown engines 369, including one engine flown twice.[15]
Rutherford is named after renowned New Zealand-born scientistErnest Rutherford. It is a smallliquid-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.[5][6] To reduce its cost, it uses theelectric-pump feed cycle, being the first flight-ready engine of such type.[4] It is fabricated largely by3D printing, using a method called laser powder bed fusion, and more specifically Direct Metal Laser Solidification (DMLS®). Its combustion chamber, injectors, pumps, and main propellant valves are all 3D-printed.[16][17][18]
As with allpump-fed engines, the Rutherford uses arotodynamic pump to increase the pressure from the tanks to that needed by the combustion chamber.[4] 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.[19]
The pumps (one for the fuel and one for the oxidizer) inelectric-pump feed engines are driven by anelectric motor.[19] The Rutherford engine uses dualbrushless DC electric motors and alithium polymer battery. It is claimed that this improves efficiency from the 50% of a typicalgas-generator cycle to 95%.[20] However, the battery pack increases the weight of the complete engine and presents an energy conversion issue.[19]
Each engine has two small motors that generate 37 kW (50 hp) while spinning at 40 000 rpm.[20] 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.[21]
The engine isregeneratively cooled, meaning that before injection some of the coldRP-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.
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