Los Angeles, California-based Relativity Space is an orbital launch company founded in December 2015 by Jordan Noone, who serves as Executive and Tim Ellis, who serves as CEO at Relativity Space.
Relativity just received $140 million worth of Series C funding towards its overarching aim of being the first company to launch an (almost) entirely 3D printed rocket into orbit. Relativity plans on 3D printing about 95 percent of a rocket, compared to other companies like SpaceX, Blue Origin, Rocket Lab, and others who only 3D print selected parts.
Ellis claims that the heart of Relativity’s robotic rocket factory is Stargate, a massive metal 3D printer that is possibly the largest in the world. The giant 3D printer, with its 20-foot-long arms. unlike traditional 3D printers, works with molten metal that is heated up by lasers.
To print a large component, such as a fuel tank or rocket body, the printer feeds miles of a thin, custom-made aluminum alloy wire along the length of an arm to its tip, where a plasma arc melts the metal, according to Wired.
The arm then deposits the molten metal in thin layers, orchestrating its movements according to patterns programmed in the machine’s software. Meanwhile, the printer head at the tip of the arm blows out a non-oxidizing gas to create a sort of “clean room” at the deposition site.
Relativity now has a new version of Stargate and it is twice as tall as the original and only has two arms. However, it can 3D print bigger rocket components at a single go – like the rocket’s fairing or fuel chambers. Ellis – looking to the future – said its next Stargate will double in size yet again, which will eventually allow the company to produce larger rockets.
To print smaller rocket parts, Relativity used commercially available 3D printers because these parts require more precision. Relativity Space aims to build a fully autonomous factory that can fabricate a complete 90-foot-tall Terran rocket in a month or two.
The launch company is expecting to see the first flight of its Terran rocket by the year 2021. The rocket should be able to put a 2,000-pound payload into orbit. The company says the anticipated price will be $10 million, compared to Space-X’s published price of $62 million for a Falcon rocket launch.
Machine learning is the ticket
Fitting in with Relativity’s forward-thinking goal of printing a rocket on Mars, not only does the company have the huge 3D printers, but the robotic printers use machine learning algorithms. The platform allows the printer to recognize mistakes, corrects its own work, and learn from these errors to get better in the future.
Stargate also has multiple printer heads, that when coordinated together allow for increased building rates. On-board machining allows the robot to build traditionally impossible geometric shapes and Stargate is very flexible in its scalability.
As for the materials used in printing rocket parts, stronger alloys can be designed because the company has an in-house metallurgy and material characterization lab.
Ellis told Wired: “To print stuff on Mars you need a system that can adapt to very uncertain conditions. So we’re building an algorithm framework that we think will actually be transferable to printing on other planets.”
