Electron is a two-stage, expendable orbital launch vehicle developed by Rocket Lab, a publicly traded aerospace manufacturer and launch service provider. Servicing the commercial small satellite launch market, it is the third most launched small-lift launch vehicle in history. Its Rutherford engines are the first electric-pump-fed engine to power an orbital-class rocket. Electron is often flown with a kickstage or Rocket Lab's Photon spacecraft. Although the rocket was designed to be expendable, Rocket Lab has recovered the first stage twice and is working towards the capability of reusing the booster. The Flight 26 (F26) booster has featured the first helicopter catch recovery attempt. Rocket Lab has, however, abandoned the idea of catching Electron. In December 2016, Electron completed flight qualification. The first rocket was launched on 25 May 2017, reaching space but not achieving orbit due to a glitch in communication equipment on the ground. During its second flight on 21 January 2018, Electron reached orbit and deployed three CubeSats. The first commercial launch of Electron, and the third launch overall, occurred on 11 November 2018. Since then, Electron has launched successfully 89 times, with an additional 4 failures, for a total of 93 launches.
Design Electron uses two stages with the same diameter (1.2 m (3 ft 11 in)) filled with RP-1/LOX propellant. The main body of the rocket is constructed using a lightweight carbon composite material. Both stages use the Rutherford rocket engine, the first electric-pump-fed engine to power an orbital rocket. 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. There are nine Rutherford engines on the first stage and one vacuum-optimized version on the second stage. The first stage engines deliver 162 kN (36,000 lbf) of thrust and the second stage delivers 22 kN (4,900 lbf) of thrust. Almost all of the engines' parts are 3D printed to save time and money in the manufacturing process. Rocket Lab has also developed an optional third stage, known as the "kick stage", designed to circularize the orbits of its satellite payloads. The Electron kick stage is equipped with a single Curie engine that is capable of performing multiple burns, uses an unspecified "green" bipropellant, and is 3D printed. It was first used during Electron's second flight. The kick stage can transport up to 150 kg (330 lb) of payload. Rocket Lab has also developed a derivative spacecraft of the kick stage, Photon, which is intended for use on lunar and interplanetary missions. Photon will be capable of delivering small payloads of up to 30 kg (66 lb) into lunar orbit. The Electron payload Fairing is 2.5 m (8 feet and 2.4 inches) in length with a 1.2 m (3 feet and 11.2 inches) diameter and a total mass of 44 kg (97 lbm).
Production Manufacturing the carbon composite components of the main flight structure has traditionally required 400 hours, with extensive hand labor in the process. In late 2019, Rocket Lab brought a new robotic manufacturing capability online to produce all composite parts for an Electron in just 12 hours. The robot was nicknamed "Rosie the Robot", after The Jetsons character. The process can make all the carbon fiber structures as well as handle cutting, drilling, and sanding such that the parts are ready for final assembly. The company objective as of November 2019 is to reduce the overall Electron manufacturing cycle to just seven days. Rutherford engine production makes extensive use of additive manufacturing and has since the earliest flights of Electron. This allows the capability to scale production in a relatively straightforward manner by increasing the number and capability of 3D printers.
Reusability On 6 August 2019, Rocket Lab announced recovery and reflight plans for the first stage of Electron, although plans had started internally from late 2018. Electron was not originally designed to be a reusable launch vehicle as it is a small-lift launch vehicle but was pursued due to increased understanding of Electron's performance based on analysis of previous flights through sensors on the vehicle. In addition, reusability was pursued to meet launch demands. To counteract decreased payload capacity caused by the added mass of recovery hardware, performance improvements to Electrons are expected. Early phases of recovery included data gathering and surviving atmospheric reentry also known as "The Wall". The next phase will require a successful deployment of an aerodynamic decelerator or ballute to slow the booster followed by the deployment of parafoil concluded by a touchdown in the ocean. After a successful touchdown in the ocean, the stage would be moved onto a ship for refurbishment and reflight. Rocket Lab has not released information on aerodynamic decelerator that would be required to slow down the booster after atmospheric reentry. Late phases of Electron reuse would involve using a parafoil and mid-air retrieval by a helicopter. After a successful mid-air retrieval the helicopter would bring the Electron to a ship that would bring the stage to the launch site for refurbishment and launch. Later, Rocket Lab abandoned the plan to catch the stage with a helicopter, and will use ocean landing instead. One recovered Rutherford engine passed five full-duration hot fire tests and is declared ready to fly again. Rocket Lab's 40th Electron mission successfully reused a refurbished Rutherford engine from a previous flight.
Aerothermal decelerator Rocket Lab, while investigating reusability, decided that they will not pursue propulsive recovery like SpaceX. Instead they will use the atmosphere to slow down the booster in what is known as "aerothermal decelerator" technology. The exact methods used are proprietary but may include keeping proper orientation when reentering the atmosphere and other technologies.
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