Just as a sailboat is powered by wind in a sail, solar sails employ the pressure of sunlight for propulsion, eliminating the need for conventional rocket propellant.

The primary objective of the ACS3 technology demonstration is the successful deployment of the composite boom solar sail into low-Earth orbit. After reaching space, the ACS3 spacecraft will deploy its solar power arrays and then begin unfurling its solar sail via four booms that span the diagonals of the square and unspool to reach 23 feet (about 7 meters) in length.

After approximately 25 minutes, the solar sail is fully deployed, and the square-shaped solar sail measures approximately 30 feet (about 9 meters) per side, or about the size of a small apartment. A suite of onboard digital cameras will obtain images of the sail during and after deployment in order to assess its shape and alignment.

ACS3’s sails are supported and connected to the spacecraft by booms, which function much like a sailboat’s boom that connects to its mast and keeps the sail taut. The composite booms are made from a polymer material that is flexible and reinforced with carbon fiber. This composite material can be rolled for compact stowage, but remains strong and lightweight when unrolled. It is also very stiff and resistant to bending and warping due to changes in temperature.

Solar sails can operate indefinitely, limited only by the durability of the solar sail materials and spacecraft electronic systems in the space environment. The ACS3 technology demonstration will also test an innovative tape-spool boom extraction system designed to minimize jamming of the coiled booms during deployment.

Mission Objectives:

• Demonstrate successful deployment of the composite boom as well as sail packing and deployment systems in low-Earth orbit
• Evaluate the efficacy of the shape and design of the solar sail
• Characterize the thrust functionality of the sail as the spacecraft gradually changes orbit
• Collect data on the sail’s performance to inform the design of larger, more complex systems

Courtesy of NASA

Designed, manufactured, and launched by Rocket Lab, Electron 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 rideshares.

Specs

Height: 18 meters (59 feet)

Diameter: 1.2 meters (4 feet)

Payload Capacity: Up to 300 kilograms (660 pounds) to low Earth orbit (LEO)

Stages: Two-stage rocket

First Stage Engines: Nine Rutherford engines

Second Stage Engine: One Rutherford engine

Propellant: Liquid oxygen (LOX) and kerosene (RP-1)

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

Technical Specifications

Height: 18 m / 59 ft
Diameter: 1.2 m / 3.9 ft
Stages: 2 + Kick Stage
Wet mass: 13,000 kg / 28,660 lb
Payload to LEO: 300 kg / 661 lb

Electron is powered by the in-house designed and produced additively manufactured Rutherford engines.

First Stage

Electron’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.

Second Stage

Electron’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 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

Kick Stage

Rocket Lab’s Kick Stage offers our 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.

Courtesy of Rocket Lab

Rocket Lab's Launch Complex 1A (LC-1A) on the Māhia Peninsula on New Zealand's North Island is part of the company's first launch site, with another under construction at the Mid-Atlantic Regional Spaceport on Wallops Island, Virginia.

An isolated location, the Māhia launch site hosted its first orbital launch attempt of Electron in May 2017 and its first successful orbital launch in January 2018.

Together with Rocket Lab's third launch pad in Virginia, their launch sites can support up to 132 Electron launch opportunities every year.

The Māhia location has two launch pads (LC-1A and LC-1B) and two separate integration hangers to permit simultaneous and protected processing of two payloads for flight at the same time.

LC-1A is the original pad at the Māhia site, with LC-1B launching its first mission in February 2022.

Photo: Rocket Lab