Rocket Lab Prepares to Launch First Electron Rocket with 3D Printed Rutherford Engines

Two years ago, New Zealand company Rocket Lab announced that they had developed  the world’s first battery-powered rocket, and that the engine would be almost entirely 3D printed. This week or next, that rocket will finally be going into space, if everything goes according to plan. Rocket Lab has been given a window of between today and June 3 to fire the Electron rocket into orbit, as long as the weather cooperates and no last-minute technical difficulties keep the rocket grounded.

If and when the launch succeeds, it will be a first for New Zealand, which has no space program.

“If we get to orbit on the first flight, we will have done something most countries have never achieved,” said Peter Beck, founder of Rocket Lab. “The vehicle will be in a state of readiness for the next week-and-a-half. If we get a favourable met report the day before, we’ll prepare to launch.”

Determining acceptable launch conditions is a lot more complex than just looking outside to see if it’s storming or not. Equipment such as radar and weather balloons will be used to measure wind velocities and air pressure both at ground level and at higher levels. According to John Law of MetService, things are looking good for the first part of the week, meaning that the decision to fire the rocket could be made as early as today. New Zealand’s weather can change fast, though, so the plan will remain up in the air until the very last minute.

“New Zealand’s weather is unpredictable enough that there’s no point in really targeting a day. We’re just hoping during the window there’s a good probability of getting the conditions we need to launch,” said Beck. “If we don’t, we’ll close the window and open another one at a later date and go again.”

Last Tuesday, a “dress rehearsal” was conducted, with everything conducted except for the actual lighting of the ignition, right up to fueling the rocket and closing the airspace. According to Beck, however, it’s impossible to rule out any last-minute technical problems that could prevent launch, no matter how prepared the team is.

“Right now, everything is looking good. But I must stress, a launch vehicle is an incredibly complicated machine,” he said. “There’s over 20,000 sensors that we’re monitoring and if any of those sensors turn red then we won’t fly.”

It won’t be the first time that Rocket Lab has fired a rocket; in 2009, the company launched the Atea-1 suborbital sounding rocket. However, that rocket had no telemetry downlink, so determining its altitude was impossible, meaning that there’s no way to verify whether it actually reached space. That won’t be an issue with the Electron, though. In 2010, Rocket Lab was granted an Operationally Responsive Space Office (ORS) contract from the US government, leading the company to begin exploring low-cost launch systems for nanosatellites.

A low-cost launch system came in the form of the Electron, whose Rutherford engine can be 3D printed in 24 hours. The engine’s main prop valves, injectors, pumps and engine chambers are all 3D printed through electron beam melting, and the engine itself is the first of its kind, using an electric motor instead of gas and creating a more lightweight, efficient machine.

How it will work: an electric rotodynamic pump will use a rotor to deliver energy and pressure to the fuel and oxidizer as they flow down from their propellant tanks into the fuel and oxidizer pumps. The rotodynamic pumps will spin at 40,000 rpm and are actuated by a brushless DC electric motor, fed by a lithium polymer battery bank and powered by DC (Direct Current) electricity via an inverter/switching power supply which produces the Alternating Current (AC) that then drives the various phases of the motor via a closed loop controller.

“At engine start up, LOX [liquid oxygen] will flow from its propellant tank into the electric oxidizer pump, from which it will travel directly into the engines’ combustion chambers,” explained NASA, a Rocket Lab customer. “The RP-1 [refined kerosene] will likewise drain from its propellant tank into the electric fuel pump; however, it will first be directed through heat exchange tubing down the outside of the engine nozzles before travelling back up into the combustion chambers, where it will meet the LOX.”

The system is nearly 50% more efficient than traditional gas generator cycle engines. The Rutherford engine is capable of producing a maximum thrust of 5,000 lbs in a vacuum, enough to launch a 150 kg (330 lb) payload. The first Electron rocket, appropriately nicknamed “It’s a Test,” stands 17 m tall, has a diameter of 1.2 m, and weighs 10,500 kg fully fueled. Nine Rutherford engines will be used for the first stage of launch, and a single vacuum-optimized engine for the second stage.

The biggest issue in getting the rocket off the ground has been finding a suitable launch site, so Rocket Lab developed their own dedicated launch facility on New Zealand’s Mahia Peninsula. The firing of the rocket will be the first commercial launch from a fully commercial launch site, marking a new era in which small private companies compete with national space agencies to reach space more often, and more frequently. Beck has said that he hopes to eventually launch a nanosatellite-carrying rocket as frequently as once a week.

3D printing makes for a rocket that is light enough and inexpensive enough to do so. New Zealand may not have a space program, but it does have a company that’s about to make space history. Will that history happen this week? We’ll find out soon. Discuss in the Rocket Lab forum at 3DPB.com.