Relativity Space aims to not only 3D print its rocket engines but also nearly all of the booster itself. And now it has raised a considerable amount of money for a company with just 17 employees. On Tuesday, Relativity Space announced an additional $35 million round of funding to help bring its Terran rocket to market.

The funds were raised as part of "Series B" financing, a second round of venture capital fundraising in which investors pay a higher price for stock than original investors. The latest round of investment was led by Playground Global, and it included returning participation from Social Capital, Y Combinator, and Dallas Mavericks owner Mark Cuban.

According to Relativity, the new funding will allow the company to accelerate its efforts to attract launch contracts for future constellations of satellites. Already, company co-founder Tim Ellis has said Relativity has secured more than $1 billion in commitments for future orders provided it can become operational on a reasonable schedule.

Along with announcing the new round of financing, Relativity released a new video (below) showcasing the manufacturing, and a recent test firing, of its Aeon 1 engine. To test lots of engines for future flights, the company has signed a new 20-year agreement with NASA for an exclusive lease of the 25-acre E4 Test Complex at Stennis Space Center in Southern Mississippi. Full-scale tests of a flight-weight engine should come before the end of 2018.

Other companies have used 3D printing technology to manufacture components, or most of their rocket engines, such as Rocket Lab's Rutherford engine or Stofiel Aerospace and its Hermes solid-fueled rocket. However, Relativity Space is the first company to attempt to 3D print nearly all of its launch vehicle, from engines to the fairing.

For the Terran rocket, Relativity plans to integrate nine Aeon engines into the first stage with a single-engine upper stage. The Terran booster will hit what the company believes is a sweet spot between smaller rockets under development by Rocket Lab (and others) and the much larger Falcon 9 built by SpaceX. It has a planned capacity to deliver 1,250kg to low-Earth orbit and a per-launch cost of $10 million. Ellis said a test flight is presently planned for late 2020, with commercial launches beginning in 2021.