3D rocket printing for fun and profit

Even in an era during which the aerospace industry faces significant disruption from myriad new competitors, Relativity Space stands out. The company, led by a pair of twenty-somethings who used to work for Blue Origin and SpaceX, seeks to 3D print rocket engines and the boosters themselves, reducing the number of parts in an orbital rocket from 100,000 down to fewer than 1,000.

Founded in late 2015, Relativity remained in stealth mode until last year, but now it is starting to come out of the shadows. And in doing so, the California-based company is revealing some pretty outsized ambitions. One day, in fact, the company intends to 3D print a rocket on Mars for a return trip to Earth. "We have a pretty broad long-term vision," Tim Ellis, a co-founder of Relativity, admitted in an interview with Ars.

Before it reaches Mars, of course, Relativity must first successfully 3D print a rocket on Earth. Ellis said Relativity is making good progress toward that goal, having already printed engine components for test firings.

So far, Ellis said, the gamble is paying off. Building and 3D printing an engine has been, he says, "a little bit easier than expected." The metals they are using for engine chamber parts, based on their strength and grain structure, are actually 20-percent stronger and have higher ductility than similar alloys not printed using the 3D process.

Automation has allowed Relativity to remain a very lean company—it still has just 17 full-time employees at a time when it is beginning to perform full-scale and flight-weight engine tests. Turbopumps will be added to the engine tests this year for a much more flight-like configuration. Ellis said Relativity will probably expand to about 45 people by the end of this year, as it scales up production.
https://arstechnica.com/science/2018/03/relativity-space-reveals-its-ambitions-with-big-nasa-deal/