The narrative shared reveals that Relativity Space once embarked on a pioneering project to 3D print an entire rocket, a concept far ahead of traditional aerospace methods. Originating from California, the company brought forth an idea of not only printing rocket engines but also the fairings and various other structural components. This comprehensive approach to using 3D printing technology aimed to facilitate rapid iterative designs and reduce the traditional complexities of rocket assembly, thereby potentially reducing overall weight due to fewer connectors.
As part of their ambitious plan, Relativity Space developed a specialized large-format metal 3D printer named “Stargate” specifically for rocket manufacturing. Their initial creation using this technology was the Terran-1, a rocket wholly conceived from their advanced 3D printing capabilities.
In the year 2023, Terran-1’s inaugural voyage was largely a success. The rocket’s first stage performed flawlessly, yet an issue during the second stage stopped the payload from reaching its orbital destination. Prior to this, there had been significant doubts about employing a rocket with a 3D printed structure, particularly the risk of the fuselage splitting along its layered seams under stress.
However, these fears were unfounded during the test flight, which validated the viability of using 3D printing technology for rocketry.
After this success, an unexpected development occurred.
The manufacturing company decided to cease production of the Terran-1 model to focus on their next project, the Terran-R. This new rocket model, noticeably larger than SpaceX’s Falcon 9, marked a shift in manufacturing technique by opting for traditional aluminum sheeting for the fuselage instead of extensive 3D printing.
At the time of the transition, I found myself pondering if the move from 3D printing was influenced by the enormous scale of the Terran-R or if there were obstacles inherent in the 3D printing technique itself. Relativity Space remained silent on this issue.
We have since gained more insight into this shift from an article on Are Technica, written by Eric Berger.
Berger discovered a dubious image shared by Relativity Space, suggesting they had manufactured a large fairing for the Terran-R. Yet, Berger’s investigative work disclosed that the image was, in fact, showcasing a fairing for ESA’s Ariane 6 rocket.
During an interview with a co-founder of Relativity Space, Berger unearthed issues related to the 3D printing methodology:
“As for 3D printing, Relativity had experienced some growing pains with issues like cracking. The company planned to lean heavily into 3D printing for engines and other parts of the Terran R rocket. But Ellis said he could no longer claim that Terran R would be 90 percent additively manufactured.”
There’s more:
“According to internal documents reviewed by Ars, Relativity had difficulty printing pressure domes for the Terran R rocket. One of the documents references a ‘large buckling event’ with a printed dome. As a result, Relativity seems likely to purchase these pressure domes from a European aerospace company.”
Because of these issues, it appears that Relativity Space is drifting towards a design that is quite similar to the Ariane 6, likely to take advantage of parallel manufacturing.
Unfortunately, this will further decrease the proportion of 3D printed parts in the Terran-R.
This is not the greatest news for 3D printing, as it confirms the infeasibility of fully 3D printed rocketry, at least with the approach used by Relativity Space. While there have been tremendous applications of metal 3D printing in space applications, there are also limits to what is possible.
Via Ars Technica and Relativity Space