|Country of origin||United States|
|First flight||21 January 2018|
|Thrust (vac.)||27 lbf (120 N)|
Curie is a liquid-propellant rocket engine designed and manufactured by Rocket Lab. It uses a "green" monopropellant as its propellant and is used for the third stage/kicker stage of the Electron rocket as well as the Photon. It produces 120 newtons (27 lbf) of thrust, and has an unreleased specific impulse.
It was first used on 21 January 2018 during Rocket Lab's first successful orbital rocket launch, and helped to boost two small CubeSats, the weather and ship-tracking Lemur-2 CubeSats built by the company Spire Global, into a circular orbit.
The Curie engine, named after Polish scientist Marie Curie, is a small liquid-propellant rocket engine designed to release "small satellites from the constricting parameters of primary payload orbits and enables them to fully reach their potential, including faster deployment of small satellite constellations and better positioning for Earth imaging". It is 3D printed.
The Electron third stage, which is powered by Curie, is equipped with its own reaction control system, avionics, power, and communication systems. During the first flight in January 2018 where Curie was tested, the Electron third stage also referred to as the "kick stage", coasted for roughly 40 minutes after successfully deploying an Earth-imaging Dove satellite built by the company Planet Labs, and then ignited the Curie engine on its first in-space test. After this test, the stage was left in orbit. However, Rocket Lab stated that future launches would have the stage deorbited after releasing their payloads to prevent addition to space debris.
While Rocket Lab is not known to have specified the monopropellant used by Curie, in 2012 Rocket Lab demonstrated the use of a non-toxic Viscous Liquid Monopropellant (VLM) that it had developed.