[[Home|🏠]] <span style="color: LightSlateGray">></span> [[Hardware]] <span style="color: LightSlateGray">></span> Rutherford
## Summary
Rutherford is a liquid-propellant rocket engine designed by Rocket Lab and manufactured in Long Beach, California. It uses LOX (liquid oxygen) and RP-1 (refined kerosene) as its propellants and is the first flight-ready engine to use the electric-pump-fed cycle. The rocket uses a similar engine arrangement to the Falcon 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 an octaweb. The sea-level version produces 24.9 kN (5,600 lbf) of thrust and has a specific 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).
đź”— https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)
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## Specifications
| Spec | Value |
| ---------------------------------------- | ----------------------------------------------------------------------------------------------- |
| **Lift-off Thrust (sea level / vacuum)** | 25 kN / 26 kN |
| **ISP (sea level / vacuum)** | 311 s / 343 s |
| **Cycle** | Electric-pump-fed |
| **Thrust to Weight Ratio** | 72.8 |
| **Dry Mass** | 35 kg |
| **Diameter** | .25m / 9.8 in |
| **Propellant** | [LOX](https://en.wikipedia.org/wiki/Liquid_oxygen) / [RP-1](https://en.wikipedia.org/wiki/RP-1) |
The Rutherford engine’s production scalability is facilitated by additively manufactured, or 3D printed, primary components. With a 3D printed combustion chamber, injectors, pumps, and main propellant valves, Rutherford has the most 3D printed components of any rocket engine in the world. These primary components can be printed in 24 hours, drastically reducing production timelines compared with traditional production methods. Rutherford engines are manufactured at Rocket Lab’s headquarters in Long Beach, California.
Instead of being powered by traditional gas turbine pumps, Rutherford uses a cycle of brushless DC electric motors and high-performance lithium polymer batteries to drive its propellant pumps. This cuts down on much of the complex turbomachinery typically required for gas generator cycle engines, meaning that the Rutherford is simpler to build than a traditional engine but still can achieve 90% efficiency.
## Electric Pumps
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% ([Source](https://web.archive.org/web/20160304053054/http://aviationweek.com/space/rocket-lab-unveils-battery-powered-turbomachinery)). However, the battery pack increases the weight of the complete engine and presents an energy conversion issue.
Each engine has two small motors that generate 37 kW (50 hp) while spinning at 40 000 rpm. 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.
![[Pasted image 20250720171454.png]]
## Battery Hot Swap and Jettison
The electric pumps are powered by lithium-polymer batteries. The second stage uses three batteries which are "hot swapped", two of the batteries are jettisoned once depleted to shed mass.
đź”— Backup Link: https://youtu.be/yD0qIdUOYnU?t=1483
## Testing + Qualification
First test-firing took place in 2013. The engine was qualified for flight in March 2016 and had its first flight on May 25th 2017.
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