Electron Rocket; Rocket Lab Space Launch Vehicle.

Electron Rocket lifts off from Rocket Lab LC-1 Pad A

Electron Rocket is an orbital launch vehicle designed specifically to place small satellites of up to 300 kg / 660 lbm into a wide range of low Earth orbits (LEO). It is 18 m (59 ft) tall with a diameter of 1.2 m (3 ft 11 in) and total mass of 12.5 t (28,000 lb). Every aspect of Electron has been designed for frequency and reliability to meet the evolving needs of government and commercial small satellite operators.

Illustration of Electron Rocket on Launch Platform
Electron Rocket on Launch Platform

The two-stage, partially recoverable orbital launch vehicle developed by Rocket Lab, an American aerospace company with a wholly owned New Zealand subsidiary. 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. Rocket Lab has recovered the first stage twice and is working towards the capability of reusing the booster.

Electron’s Flight Heritage

Since its first launch in 2017, Electron Rocket has become the leading launch vehicle dedicated to small satellites and one of the most frequently launched orbital rockets in the world. More than 50 satellites have been deployed to orbit by Electron for commercial and government partners, including NASA, the U.S. Air Force, DARPA, and the National Reconnaissance Office.

Electron Rocket lifts off from Rocket Lab LC-1 Pad A
Electron Rocket lifts off from Rocket Lab LC-1 Pad A

Electron Features, Design and overview

Designed, manufactured, and launched by Rocket Lab, Electron Rocket is a two-stage launch vehicle powered by liquid oxygen (LOx) and rocket-grade kerosene (RP-1). By incorporating an orbital transfer vehicle stage (Kick Stage) that can deploy multiple payloads to unique orbits on the same mission, Electron can support dedicated missions and rideshare options without the complexity and schedule risk typically associated with launching on medium or heavy lift launch vehicles.

Electron Rocket utilizes advanced carbon composite technologies throughout the launch vehicle structures, including all of Electron’s propellant tanks. The all carbon-composite construction of Electron decreases mass by as much as 40 percent compared with traditional aluminum launch vehicle structures, resulting in enhanced vehicle performance. Rocket Lab fabricates tanks and other carbon composite structures in-house to improve cost efficiency and drive rapid production.

Electron Rocket is powered by the in-house designed and produced additively manufactured Rutherford engines. Since its first launch in 2017, Rocket Lab has released additional performance from Rocket Lab’s Rutherford engines boosting the Electron’s total payload lift capacity up to 300 kg / 660 lbm.

Electron’s First Stage

Electron Rocket’s first stage consists of nine sea-level Rutherford engines, linerless common bulkhead tanks for LOx and RP-1, and an interstage.

Rocket Lab’s flagship engine, the 5,600 lbf (24 kN) Rutherford, is an electric pumped LOx/ kerosene engine specifically designed for the Electron launch vehicle. Rutherford adopts an entirely new electric propulsion cycle, making use 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 can achieve 90% efficiency. 130 Rutherford engines have been flown to space on Electron as of July 2020.

Rutherford is also the first oxygen/hydrocarbon engine to use additive manufacturing for all primary components, including the regeneratively cooled thrust chamber, injector pumps, and main propellant valves. The Stage 1 and Stage 2 Rutherford engines are identical, with the exception of a larger expansion ratio nozzle for Stage 2 for improved performance in near-vacuum-conditions. All aspects of the Rutherford engines are completely designed in-house and are manufactured directly at our Long Beach headquarters in California, USA.

Electron Rocket Rutherford Engines and layout
First Stage Rutherford Engine (Left) & Rutherford Stage 1 Configuration (Right)

Electron Rocket Second Stage

Electron Rocket’s second stage consists of a single vacuum optimized Rutherford engine, and linerless common bulkhead tanks for LOx and kerosene. With an expanded nozzle, Electron’s second stage engine produces a thrust of 5,800 lbf and has a specific impulse of 343 sec.

The 1.2 m diameter second stage has approximately 2,000 kg of propellant on board. The Electron Stage 2 has a burn time of approximately five minutes with a Rutherford vacuum engine as it places the Kick Stage into orbit.

High Voltage Batteries (HVBs) batteries provide power to the LOx and kerosene pumps for the high-pressure combustion while a pressurant system is used to provide enough pump inlet pressure to safely operate. During the second stage burn, two HVBs power the electric pumps until depletion, when a third HVB takes over for the remainder of the second stage burn. Upon depletion, the first two HVBs are jettisoned from Electron to reduce mass and increase performance in flight.

The engine thrust is directed with electromechanical thrust vector actuators in two axes. Roll control is provided via a cold gas reaction control system (RCS).

Electron Rocket Kick Stage

Rocket Lab’s Kick Stage offer customers unmatched flexibility for orbital deployment. The Kick Stage is a third stage of the Electron launch vehicle used to circularize and raise orbits to deploy payloads to unique and precise orbital destinations. The Kick Stage is powered by Rocket Lab’s in-house designed and built Curie engine.

In its simplest form, the Kick Stage serves as in-space propulsion to deploy payloads to orbit. It its most advanced configuration the Kick Stage becomes Photon, Rocket Lab’s satellite bus that supports several-year duration missions to LEO, MEO, Lunar, and interplanetary destinations.

Electron Rocket kick stage & Second Stage
Electron Rocket kick stage (Front) & Second Stage (Behind)

Electrons Rocket Fairing

Electron Rocket’s payload fairing protects the payload from encapsulation through flight. Electron’s payload fairing is a composite split clam shell design and includes environmental control for the payload. During separation, each half of the fairing is designed to rotate on a hinge away from the payload, resulting in a safe separation motion. Expanded and tailored fairing options are available.

Electron Rocket Fairing
Rocket Lab’s fairing in clean room 1 after encapsulation at Launch Complex 1

Electron Rocket Flight Profile

In the launching of and electron rocket, payload deployment occurs approximately 3,000 seconds after liftoff for a standard dedicated mission to low Earth orbit. In this scenario, Electron’s second stage inserts the Kick Stage into a low elliptical orbit, before the Kick Stage initiates a burn of the Curie engine to circularize into the final orbit. For rideshare missions requiring multiple deployments, as well as those requiring higher orbits, the Kick Stage performs multiple engine burns to raise orbits and deploy to different, precise orbits for each payload.

Electron Launch History

In December 2016, Electron Rocket 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, due to it still being a test flight called “It’s a Test”. During its second flight on 21 January 2018, Electron reached orbit and deployed three CubeSats, in a mission called “Still Testing”. The first commercial launch of Electron, and the third launch overall, occurred on 11 November 2018, in a mission called “It’s Business Time”.

The Electron Rocket has flown 21 times since May 2017, with a total of 18 successes and 3 failures. In August 2019, a mission named “Look Ma, No Hands” successfully delivered four satellites to orbit, and in October 2019, the mission named “As the Crow Flies” successfully launched from Mahia LC-1, deploying a small satellite and its kick stage into a 400 km parking orbit. In July 2020, the thirteenth Electron rocket launch failed with customer payloads on board, the first failure after the maiden flight. In May 2021, the twentieth launch also failed.

Electron Reusability

Peter Beck the Founder and Chief Executive of Rocket Lab believes the project cost of $100m to get to orbit was too much, and probably too the Cost per launch estimated at about US$7.5 million and reusability would by far lessen the general launch cost.

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 Rocket 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 though 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 rocket reuse will 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.

Electron 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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