Our Sites

The Stargate 3D printer is being used to build rockets

Additive manufacturing is reaching new heights as Relativity Space uses building-size, custom-built 3D printing equipment to manufacture spacecraft

The sky’s the limit for a small Los Angeles-based startup with big plans for its building-size 3D printer.

The firm, Relativity Space, was launched by former college classmates Tim Ellis and Jordan Noone. After graduation, Ellis was hired by Blue Origin and Noone signed on with SpaceX, two high-profile spaceflight companies with famous founders (Jeff Bezos and Elon Musk, respectively).

Ellis and Noone reconnected in 2015 and decided to start a competing firm. The founders distinguished their company from Blue Origin and SpaceX by setting a novel and ambitious goal: be the first to 3D-print an entire rocket.

The venture has drawn financial support from numerous well-known sources, including billionaire investor Mark Cuban.

Why Print a Rocket?

There’s more to Relativity’s focus on 3D printing than just its novelty value. For one thing, printing a rocket drastically reduces part count, thereby boosting the strength and stability of the structure. Other benefits include simplified assembly, a streamlined supply chain, and greater freedom in the design of part geometries.

According to Noone, Relativity’s chief technology officer, printing also speeds up the process of turning new designs into manufactured parts. To accommodate a design change, “you’re not spending years retooling a factory,” he said. “All you’re doing is changing software.”

In addition, he noted, Relativity’s singular focus on printing slashes overhead, since the company needn’t concern itself with managing the processes and equipment used in conventional rocket manufacturing.

Relativity is currently developing a launcher and rocket engine that it plans to use to deploy and resupply satellite constellations. The launch vehicle, called Terran 1, will be an expendable two-stage rocket.

To make its rockets, Relativity will use two printing technologies. One is direct metal laser sintering (DMLS), for producing detailed, smaller components. The company has already used DMLS to produce many prototypes of its Aeon 1 rocket engine, which comprises about 100 different parts.

3D Printing on a Large Scale

According to Noone, powder-bed printing technologies such as DMLS are becoming common in the aerospace industry. But he noted that DMLS printers and technology are too small and limited in scale to manufacture an entire rocket.

stargate 3d printer

Rocket man Jordan Noone looks at Stargate, the 3D printer his company is using to build the first all-3D-printed spacecraft. Stargate features an industrial robot arm with an end effector that houses arc- and laser-deposition technologies.

He said some organizations have addressed the challenge of large-scale printing and worked on solutions, but they never developed a technology to the point that it could produce components of the quality and complexity required for rockets.

This lack of a suitable large-scale 3D printer led Relativity develop its own. Called Stargate, the company claims it is the biggest such printer of its kind in the world. The Stargate printing system sits in a cube-shaped structure measuring about 20 feet on a side. Capable of printing components as large as 9 ft. in diameter and about 15 ft. high, Stargate will print all the fuel tanks and other rocket components bigger than about 1 cu. ft., Noone said.

Noone came up with the original Stargate design in early 2016. Relativity subsequently hired a team to develop more advanced versions of the printer.

“Our goal was to develop a printer that could streamline complicated assemblies by printing them in one piece,” said Noone, who leads the development team. “We architectured a printer that was ideal for our rocket launch vehicle, which is a long, skinny tube with thin walls and unique material properties and inspection criteria.”

Developing the world’s largest 3D metal printer required expertise in a variety of fields. “We had to tackle challenges in areas such as physics, metallurgy, controls, machine learning, big data, and CAM,” Noone said. And since nothing like Stargate had ever been built before, “there was no knowledge base or research for us to reference.”

The Stargate 3D Printer Isn't EBAM

One printing option that was rejected was electron beam additive manufacturing (EBAM®), which must be performed in a vacuum chamber. The designers viewed that as an impediment to making a large printer. In addition, Relativity planned to print primarily aluminum alloys, which boil in a vacuum.

As with EBAM, though, Relativity feeds a wire-based material into its printer. To melt and fuse the material during the printing process, Stargate uses a high-powered laser and plasma arc technology. A vacuum chamber isn’t required, since both the arc and laser machines can function in a normal atmosphere.

The combination also allows Stargate to control thermal input sufficiently to produce the required part properties and geometries, Noone explained.

Stargate’s patented printing system features an industrial robot arm with an end effector that houses the arc- and laser-deposition technology. An array of sensors surrounds the deposition system and constantly collects data, providing the real-time control necessary to ensure that printing is done with the required precision.

Each printing process generates about 10 terabytes of data, which Relativity analyzes after a build session in an ongoing effort to improve process control.

Terran 1 rocket

Thanks to 3D printing, the Terran 1 design has fewer than 1,000 parts, compared to the nearly 100,000 in conventional rockets.

In addition to the robot arm with the deposition head, the Stargate cube houses two other robot arms that are used for in-situ postprocessing. During the printing process, these arms can be used to produce a fine surface finish in certain places on the part.

Though Relativity currently focuses mainly on aluminum alloys, Stargate can print any weldable material, as well as certain nonweldable materials that respond well to the process. As development of Terran 1 has proceeded, Relativity has started exploring the use of materials such as stainless steel and nickel alloys.

In the development of Terran 1, Relativity reports that 3D printing has allowed it to change designs quickly and use less tooling and labor than would normally be required in rocket development.

And thanks to printing, the Terran 1 design has fewer than 1,000 parts, compared to the nearly 100,000 components in conventional rockets, Noone said, adding that Terran will have a “radically simple” supply chain.

An Ambitious Agenda for the Stargate 3D Printer

Relativity aims to print at least 95 percent of its launchers, by weight, with about half the components made by Stargate and the other half by DMLS. The production process can go from raw material to flight-ready rocket in less than 60 days.

For testing purposes, Relativity leases space at the Stennis Space Center in Mississippi, where it has completed more than 100 test firings of its Aeon 1 engine. In addition, the company will build and operate a launch complex at Cape Canaveral. Relativity plans to launch its first Terran rocket from the site in late 2020 and start its commercial satellite-launch service soon afterwards.

Beyond that, Relativity aims to be the first to produce and launch printed rockets on Mars. “The company’s vision is to build the future of humanity in space, starting with rockets,” Noone said.

As for Stargate, Relativity now has four of the large printers, which will soon be turning out parts for the first Terran rocket. Nevertheless, Noone and his team continue to work on improving their design, focusing on areas such as increasing part strength to save weight and further reducing rocket part count. The latter could involve making Stargate even larger. “Our rocket is about 105 ft. tall, and we make it in sections and join them. We see a future where we are able to make more of the rocket at one time,” Noone said, further reducing part count and assembly.

No matter what changes and improvements are made to Stargate, Noone said he and his team may never be satisfied with their creation. “I don’t know if we will ever call it a ‘finished’ product.”

Terran's (rocket) engine contains 3d printed parts

Relativity Space uses a DMLS 3D printer to build the Terran’s engine (shown), which is comprised of fewer than 100 parts, and other smaller parts of the rocket. The patented Stargate 3D-prints fuel tanks and other large components.

About the Author

William Leventon

(609) 926-6447

William Leventon is a freelance writer specializing in technology, engineering, manufacturing, and industrial processes.