Rocket Lab designs and builds its engines in-house — from the 3D-printed, electric-pump-fed Rutherford on Electron to the reusable methalox Archimedes powering Neutron. The in-space Curie and HyperCurie engines also propel the Photon spacecraft.
Engine Operational
Rutherford
The world's first 3D-printed, electric-pump-fed orbital rocket engine.
Rutherford is Rocket Lab's small liquid bipropellant engine and the first orbital-class engine to fly an electric-pump-fed cycle — brushless DC motors and lithium-polymer batteries drive the LOX/RP-1 pumps instead of a conventional turbopump. Most of the engine, including the chamber, injector, pumps and valves, is 3D printed, letting Rocket Lab build engines in roughly a day. A sea-level variant clusters nine-strong on Electron's first stage; a vacuum-optimized variant powers the second stage. Flight-proven Rutherfords have been recovered and re-fired as part of Electron reuse.
- Type
- Electric-pump-fed liquid bipropellant
- Cycle
- Electric-pump-fed (battery-driven brushless DC motor turbopumps)
- Propellants
- RP-1 (kerosene) + liquid oxygen (LOX)
- Thrust (SL)
- 24.9 kN (5,600 lbf)
- Thrust (vac)
- 25.8 kN (5,800 lbf), vacuum variant
- Isp (SL)
- 311 s
- Isp (vac)
- 343 s
- Mass
- ≈29.5–35 kg (65–77 lb)
- Manufacturing
- 3D-printed via laser powder-bed fusion (DMLS)
- First flight
- 25 May 2017 ('It's a Test', Electron Flight 1)
Used on
Electron Stage 1 (9× sea-level, gimballed)Electron Stage 2 (1× vacuum-optimized)
Key facts
- ▸ First flight-ready engine to use the electric-pump-fed cycle, replacing a turbopump with battery-powered electric motors.
- ▸ World's first 3D-printed engine to reach orbit.
- ▸ Nine on Electron's first stage produce ~190 kN of lift-off thrust, peaking near 224 kN.
- ▸ Named after physicist Ernest Rutherford. Mass is not officially published — a flight unit at the Smithsonian is listed at 29.5 kg (65 lb); 35 kg (77 lb) is also widely cited.
- ▸ Recovered and re-fired as part of Electron first-stage reuse.
Engine Operational
Curie
A compact, restartable in-space engine for precision orbital delivery.
Curie is Rocket Lab's 3D-printed, pressure-fed liquid bipropellant in-space engine using storable propellants (composition proprietary). It produces 120 N of vacuum thrust at ~320 s Isp and can re-ignite many times to circularize orbits, change planes, deorbit, and deploy satellites precisely. Curie is the propulsion for Electron's Kick Stage and the Photon spacecraft bus. It first flew on the 'Still Testing' mission in January 2018. Named after Marie Curie.
- Type
- Pressure-fed liquid bipropellant (storable; mono- and bipropellant configs)
- Cycle
- Pressure-fed (no turbopump)
- Propellants
- Storable bipropellant — composition proprietary
- Thrust (vac)
- 120 N (27 lbf)
- Isp (vac)
- ≈320 s
- Mass
- Not publicly disclosed
- Manufacturing
- 3D-printed (additively manufactured)
- First flight
- 21 Jan 2018 ('Still Testing', Electron)
Used on
Electron Kick Stage (in-space 3rd stage)Photon spacecraft bus
Key facts
- ▸ Restartable, pressure-fed in-space engine: 120 N (27 lbf) vacuum thrust at ~320 s Isp.
- ▸ Enables multiple burns for orbit circularization, plane changes, and deorbit.
- ▸ Available in monopropellant and bipropellant configurations using storable propellants.
- ▸ Exact propellant chemistry is held as a Rocket Lab trade secret.
- ▸ Named after Marie Curie; core propulsion for both the Kick Stage and Photon.
Engine Operational
HyperCurie
The hypergolic, electric-pumped engine that sent CAPSTONE toward the Moon.
HyperCurie is the higher-energy, electric-pump-fed evolution of Curie for deep-space maneuvers on Photon. It burns hypergolic propellants (which ignite on contact, removing the need for an igniter) and uses Rutherford-style electric pumps scaled for an in-space engine — fed by the spacecraft's solar arrays on interplanetary Photon. It is 3D printed. HyperCurie performed the orbit-raising and trans-lunar injection burns that sent NASA's CAPSTONE toward the Moon in 2022, demonstrating several km/s of delta-v.
- Type
- Hypergolic, electric-pump-fed liquid bipropellant (in-space)
- Cycle
- Electric-pump-fed (electric turbopumps; solar-array powered on interplanetary Photon)
- Propellants
- Hypergolic bipropellant — composition not publicly disclosed
- Thrust (vac)
- Not publicly disclosed (secondary sources report ~480 N, unconfirmed)
- Isp (vac)
- Not publicly disclosed
- Mass
- Not publicly disclosed
- Manufacturing
- 3D-printed (additively manufactured)
- First flight
- 28 Jun 2022 — NASA CAPSTONE Lunar Photon (TLI burn 4 Jul 2022)
Used on
Photon (deep-space / interplanetary)Lunar Photon (NASA CAPSTONE)
Key facts
- ▸ Hypergolic, electric-pump-fed evolution of Curie — propellants ignite on contact, eliminating a separate igniter.
- ▸ Enables >4 km/s of delta-v from LEO, supporting lunar and interplanetary transfers.
- ▸ Executed the burns that sent NASA CAPSTONE toward the Moon in 2022.
- ▸ Baselined for deep-space missions including a planned private Venus probe.
- ▸ Detailed thrust/Isp/mass figures are not officially published; cited secondary numbers conflict.
Engine In development
Archimedes
The reusable methalox staged-combustion engine powering Neutron.
Archimedes is Rocket Lab's in-house, reusable LOX/methane (methalox) engine for the Neutron rocket. It runs an oxidizer-rich staged-combustion cycle — a deliberate change from Neutron's original gas-generator design — but is run well below its limits (lower turbine temperatures and stress) for rapid, reliable reuse. Many components are 3D printed on some of the largest metal printers in the industry. Each engine makes ~733 kN at sea level (~890 kN vacuum) and throttles 50–100% for max-Q and propulsive landing. Nine power Neutron's first stage; one vacuum variant powers the second.
- Type
- Reusable methalox liquid bipropellant (sea-level + vacuum variants)
- Cycle
- Oxidizer-rich staged combustion
- Propellants
- Liquid methane (CH₄) + liquid oxygen (LOX)
- Thrust (SL)
- ≈733 kN (165,000 lbf)
- Thrust (vac)
- ≈890 kN (200,000 lbf), vacuum variant
- Isp (SL)
- ≈329 s
- Isp (vac)
- ≈365–367 s
- Mass
- Not publicly disclosed
- Manufacturing
- Largely 3D-printed (turbopump housings, pre-burner, chamber, valves)
- First flight
- In development — first hot fire Aug 2024; Neutron debut targeted Q4 2026
Used on
Neutron Stage 1 (9× sea-level, throttleable, reusable)Neutron Stage 2 (1× vacuum-optimized)
Key facts
- ▸ Reusable methalox engine on an oxidizer-rich staged-combustion cycle (switched from the 2021 gas-generator design).
- ▸ ~733 kN (165,000 lbf) at sea level; ~890 kN (200,000 lbf) in the vacuum variant.
- ▸ Neutron's first stage uses nine Archimedes (up from seven in the 2021 reveal) for ~1,450,000 lbf of lift-off thrust.
- ▸ Deliberately de-rated and run cooler to enable rapid, reliable reuse; throttles 50–100% for landing.
- ▸ First hot fire Aug 2024, full-duration hot fire Aug 2025; Neutron debut targeted Q4 2026.
