Amazon Satellites Get Boost from Aerojet Rocketdyne’s 3D Printed Rockets

In early April 2022, American spacecraft launch service provider United Launch Alliance (ULA) signed the largest commercial launch contract in history with Amazon, promising to launch 38 Vulcan Centaur rockets supporting Amazon’s ambitious Project Kuiper, an initiative to increase global broadband access through a constellation of over three thousand advanced satellites in low Earth orbit (LEO). As ULA gets ready to fulfill such a monumental task, it has decided that Aerojet Rocketdyne’s engines will provide the necessary propulsion.

An innovative aerospace and defense leader, Aerojet has provided propulsion and energetics to the space industry for years. Its RL10 propulsion system has been around for over half a century. The RL10C-X is the next evolution of the company’s RL10 upper-stage engine and contains major components – including the injector and combustion chamber – produced with the company’s industry-leading 3D printing technology.

On April 11, 2022, we learned that ULA had awarded the largest RL10 contract ever to Aerojet Rocketdyne to deliver 116 RL10C-X engines for its Vulcan Centaur rockets.

ULA’s Vulcan Rocket chosen to launch majority of Amazon’s Project Kuiper satellite constellation. Image courtesy of ULA.

Commenting on the deal, Aerojet Rocketdyne CEO and President Eileen Drake said, “The RL10 engine is the nation’s premier upper-stage engine and a true workhorse in the industry. With the RL10C-X, we’ve leveraged our industry-leading 3D-printing technology to significantly reduce the cost of the engine while at the same time increasing its performance to provide our customer with enhanced mission capability.”

The original RL10 engine has undergone nine major upgrades. In addition to orbiting hundreds of satellites and sending spacecraft to explore every planet in our solar system, the engine powered the DC-X vertical takeoff and landing vehicle in the 1990s and has demonstrated a deep-throttling capability for NASA down to 10 percent of rated thrust, making it ideal for the sizeable lunar lander and future Mars lander applications.

Capitalizing on successful engine technology

In 2018, Aerojet announced the development of the RL10C-X in conjunction with the U.S. Air Force and United Launch Alliance, which already had plans to use the engine to power the Centaur upper stage of its Vulcan Centaur launch vehicle. This updated version of the RL10 uses advanced technologies, primarily additive manufacturing, to lower production costs while maintaining performance and reliability.

Its core is made entirely of 3D printed parts; both its main injector and combustion chamber are additively manufactured, as well as a 94-inch monolithic lightweight composite (carbon-carbon) nozzle. The RL10C-X creates thrust in 461 seconds, which puts it near the very top of the RL10 engine family in terms of performance.

Following a deliberate and proven development path that began with 3D printing and testing subscale components, the development of the RL10C-X then progressed to full-scale thrust chamber testing. This was followed by the incorporation and successful testing of a new re-generatively cooled nozzle that was 3D printed from a nickel-based alloy, which led to the testing of a full-scale engine system at sea level in 2019.

Designed, fabricated, and assembled at Aerojet Rocketdyne’s facility in West Palm Beach, Florida, the RL10C-X demonstrated full mission capability during an altitude hot fire test series in May 2021, when the engine successfully proved it could withstand both long-duration operation and engine ignition at extreme in-flight conditions. To date, the RL10C-X development program has accumulated more than 5,000 seconds of full engine hot-fire time, and 32 starts to date.

Considering that well over 500 RL10 engines have flown in space during nearly six decades of operation, the RL10C-X has neat chances of following its predecessor’s footsteps. In addition, Drake pointed out that Aerojet’s extensive experience building rocket engines for most of the nation’s preeminent launch vehicles are a solid base for the company to continue that legacy with the RL10C-X engine.

3D Printed RL10C-X Prototype Rocket Engine Soars Through Initial Round of Testing. Image courtesy of Aerojet Rocketdyne.

Powering 38 upcoming launches on ULA’s Vulcan Centaur rocket, which will have its first liftoff as early as this year, the RL10X-C will help carry Amazon’s ambitious Project Kuiper broadband internet constellation to orbit. If all goes according to plan, then Aerojet will need to supply its engines sometime this decade since the Federal Communications Commission (FCC) license requires Amazon to launch at least half of its planned 3,236-satellite constellation by 2026.

Aiming to compete with SpaceX’s Starlink internet satellite constellation, Amazon signed a deal with three companies, including ULA, to secure as many as 83 launches on three types of heavy-lift rockets to put more than 1,500 satellites into LEO over the course of five years. Although it might be difficult to surpass SpaceX at this point, notably since the space giant has already deployed 1,469 Starlink satellites into orbit and is targeting a total of 30,000, it’s always great to learn about more engines with 3D printed parts driving the space revolution of the next decade.