Even at a time when the aerospace industry is being seriously disturbed by countless new competitors, Relativity Space stands out. The company, led by two twenty-year-olds working for Blue Origin and SpaceX, is trying to print 3D rocket engines and the boosters themselves, reducing the number of parts in an orbital rocket from 100,000 to less than 1,000.  The Theory of Relativity, established in late 2015, remained in stealth mode until last year, but now it's starting to get out of the shadows. And while the California company reveals some exaggerated ambitions. One day, the company intends to print a rocket on Mars for a return trip to Earth. "We have a pretty long-term vision," admitted Tim Ellis, a co-founder of the Theory of Relativity, in an interview with Ars.
Before it reaches Mars, relativity must first successfully launch a rocket on Earth. Ellis said Relativity is making good progress toward this goal after having already printed engine components for test burners. (The company has so far performed more than 85 engine tests of various kinds). Now the company has taken an important step towards more engine test ignitions.
Relativity announced Wednesday that it has signed a 20-year partnership with NASA's Stennis Space Center for an exclusive lease of 25-acre E4 test complex in southern Mississippi. The four on-site test rigs will allow Relativity to develop and test enough engines to build 36 missiles a year. The agreement includes an option for the company to expand its presence on the site to 250 acres.
Ellis said this is the first agreement to launch a commercial spaceport that Stennis has signed. As part of these agreements, NASA locations with launch facilities will be able to share them with the private sector. Kennedy Space Center has made similar agreements, such as: For example, the deal that allows SpaceX to use Launch Complex-39A. The Stennis agreement allows the relativity to test 24 hours a day, seven days a week, as Ellis said, and used construction site and contract work as needed. The company estimates the partnership at $ 30 million.
Unlike SpaceX, which built engines in McGregor, Texas, or Blue Origin, a test site in West Texas, Ellis said he was looking to partner with NASA to avoid similar infrastructure costs. "With this partnership, we do not really have to reinvent the wheel," he said. "Since we use the site exclusively, we do not have to ask for permission if we want to test it."
Relativity is working intensively on the development of its rocket engine Aeon 1, which uses a mixture of oxygen and methane fuels. The Aeon engine has a modest vacuum surge of about 19,500 pounds, less than a tenth of a Merlin 1D engine used in SpaceX's Falcon 9 rocket. It's also nearly four times stronger than the small Rutherford engines that drive Rocket Lab's smaller electron rocket.
The key to the Aeon engine is not so much its raw performance, but its lack of complexity. Ellis said the engine could be printed in less than 20 days, accelerating the development and testing cycle. In addition, the Aeon engine has only 100 parts, compared to a few thousand for most other engines.
For its first rocket, Relativity plans to integrate nine Aeon engines into the first stage of its Terran rocket with a single-engine uppercarriage stage. The Terran Booster will hit an area that the company believes is a "sweet spot" between smaller rockets developed by Rocket Lab (and others) and the much larger Falcon 9. It has a planned capacity of 1,250 kg to the near-Earth orbit. Start costs of 10 million US dollars.
Ellis said a test flight is currently scheduled for late 2020, with commercial launches in 2021. (As always, missile development plans are subject to a delay). At this price, there seems to be a healthy market as relativity has promised more than $ 1 billion for future orders, provided it can be put into operation on a reasonable schedule.
The company has a clear-cut vision far-off that ultimately all missiles are 3D printed because the highest cost today is human labor. "We really feel that way, extrapolating into the future, if we 3D print 90 to 95 percent of the components of a rocket, we would have a launcher that would be very disturbing," said Ellis. "Basically, this is the cheapest possible rocket."
Prior to Relativity, he worked at Blue Origin and helped develop the company's high-performance BE-4 rocket engine. He pleaded for the introduction of 3D printing of metals in the production process. Co-founder of Relativity, Jordan Noone, worked at SpaceX on the crew of the DragonDriver SuperDraco bow thruster program.
Both Ellis and Noone were interested in 3D printing and felt like two of the most innovative aerospace companies Origin and SpaceX have not pushed the technology far enough. So they founded relativity. They believe that 3D printing not only has the potential to dramatically reduce costs, but also to iterate new designs quickly and make them scalable to much larger vehicles.
So far, according to Ellis, the game is worth it. Building and 3D printing is an engine, he says, "a bit easier than expected." The metals they use for engine compartment parts are actually 20 percent stronger due to their strength and grain structure and have higher ductility than similar alloys not printed in the 3D process.
Automation has given a very light weight to the theory of relativity-it has only 17  full-time employees at a time when it begins to perform full-scale and airborne engine tests. Turbopumps will be added to the engine tests this year to get a much more flight-like configuration. Ellis said that by the end of this year, relativity is likely to increase to around 45 people as it increases production.
Listing image by Relativity Space