Relativity Space will print the entire rocket

In the aerospace industry, many new companies are created annually, however, Relativity Space stands out among them. The company, led by two young entrepreneurs who previously worked for Blue Origin and SpaceX, aims to produce rockets created using additive technology, reducing the number of parts in an orbiting rocket from 100,000 to less than 1,000.
In the foreground on the left is a printed test sample .

Founded in late 2015, Relativity remained hidden until last year, but now it is beginning to emerge from the shadows. And while the California company reveals its ambitious plans. One fine day, the company intends to print a rocket on Mars to return to Earth. “We have a fairly broad long-term vision,” said Tim Ellis, one of the founders of Relativity, in an interview with Ars Technica.

Before the company reaches Mars, Relativity Space must first successfully create rockets on Earth. Ellis said Relativity has made significant progress toward this goal by already printing engine components for test burns. To date, the company has completed more than 85 fire tests of engines of various types.

Agreement with NASA

Relativity Space announced on Wednesday that it has signed a 20-year partnership with NASA Stennis Space Center (NASA SSC) for the exclusive rental of the 25-acre E4 test facility in South Mississippi. Four test benches in the complex will allow Relativity to develop and test enough engines to build 36 missiles per year, and the agreement includes the opportunity for the company to ultimately expand its presence to 250 acres.

Test site at the E4 NASA SSC complex.

Ellis said that this is the first commercial space agreement signed with the Stennis Space Center - under these agreements, NASA launch facilities can also be used by the private sector. Kennedy Space Center used similar agreements, such as a deal allowing SpaceX to use Launch Complex-39A. This agreement allows Relativity to test 24 hours a day, seven days a week, Ellis said. The company estimates the partnership at $ 30 million.

Unlike SpaceX, which built new engine testing facilities in McGregor, Texas, or Blue Origin, which has a West Texas test site, Ellis said he sought to partner with NASA to avoid similar infrastructure costs. “With this partnership, we really don't need to reinvent the wheel,” he said. “Since we have the right to use the test suite exclusively, we don’t need to ask for permission when we want to test something.”

Driving force


Relativity Space is well advanced in developing the Aeon 1 rocket engine, which uses a mixture of oxygen and methane. The Aeon engine has a modest traction in vacuum of about 19,500 pounds, which is less than 10% of the Merlin 1D engine used in the Falcon 9 rocket. However, it is almost four times more powerful than the small Rutherford engines that stand on the smaller Rocket Lab Electron rocket size.

Testing the Aeon engine
The main thing in the Aeon engine is not so much its performance as the lack of difficulty in manufacturing. Ellis said the engine can be printed in less than 20 days, which speeds up the development and testing cycle. In addition, the Aeon engine has only 100 parts, compared with several thousand for most other engines.

Stargate is the largest metal printing printer developed by Relativity Space.

The Terran rocket will soon leave the laboratory walls and rush into orbit, bringing closer the start of commercial operation. For its first rocket, Relativity plans to combine nine Aeon engines in the first stage with one engine in the upper stage, which is already becoming the standard. Terran launch vehicle is aimed at that part of the market that lies between the Electron rockets from Rocket Lab (and others) and the much larger Falcon 9. It has a planned payload of 1,250 kg for delivery to low Earth orbit, the launch cost is $ 10 million. A test launch is currently scheduled for late 2020, and commercial launches will begin in 2021. As always, missile development schedules are delayed.

Long term vision

The company has a clear vision that, ultimately, all missiles will be printed in large 3D printers, because today the biggest cost is the cost of human labor. “We really feel, extrapolating into the future, if we can use 3D printing for 90-95 percent of the components of the rocket, we will have a launch rocket that will be a painful blow for competitors,” Ellis said. “This is the cheapest rocket possible.”

Prior to Relativity, Ellis was an intern and then worked at Blue Origin, helping develop the BE-4 rocket engine. He participated in the creation of a business case for the introduction of 3D printing with metals in the production process. Relativity co-founder, Jordan Noon, worked for SpaceX with the SuperDraco program, which was used for the Crew Dragon spacecraft.

Both Tim and Jordan were interested in 3D printing and felt that two of the most advanced companies in the aerospace industry Blue Origin and SpaceX were not pushing the technology far enough. Therefore, they founded Relativity. They believe that three-dimensional printing can not only significantly reduce costs, but also allow them to quickly redo and scale new designs.

Cheaper, faster, easier

3D printed car parts are now commonplace. Ellis still believes the game is worth the candle. According to him, the creation and 3D printing of the engine is "a little easier than expected." The metals they use for parts of the engine chamber, depending on their strength and 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 small company - it still has only 17 full-time employees at the time it begins to perform flight tests. Turbo pumps close to the flight configuration will be added to engine tests this year. Ellis said that by the end of this year, the staff will expand to about 45 people, as production will expand.

Source: Ars Technica
Company website: Relativity Space