The ambitious rocket company Relativity announced its first customer on Friday, the global satellite operator Telesat. The contract for flights on the Terran 1 rocket includes "multiple" launches, but Relativity chief executive Tim Ellis said he could not provide additional details.

"This is a monumental contract for Relativity," Ellis told Ars in an interview. Although this is the first contract the company has chosen to announce, he said, Relativity has signed other binding deals earlier.

Relativity considers this a huge win because it offers another validation of its—and really, this is not an exaggeration—revolutionary approach to launch. The company aspires to use large 3D printers to manufacture nearly the entirety of a rocket, thereby automating the process and taking another step toward low-cost, launch-on-demand service. It's one thing for a private company to build a new rocket to launch small satellites, it's another to try and remake the manufacturing process as well.

Ellis said Telesat has been in discussions with Relativity for awhile, so the satellite operator has had good access to Relativity's launch technology. After this due diligence, Telesat chose Relativity in addition to previous deals with SpaceX, Arianespace, and Blue Origin. Effectively, Telesat has decided that Relativity's Terran 1 booster, with a capacity of 1.25 tons to low Earth orbit, has the right stuff to help launch a major low Earth orbit satellite constellation that will provide global broadband connectivity.

"It’s amazing, especially when you look at Telesat's track record," Ellis said. "We're joining the ranks of some of those blue-chip companies."

Ellis compared the Telesat deal to an announcement by SpaceX in 2011, when that company inked its first major commercial customer for the Falcon 9 rocket with fleet operator SES. This became the SES-8 mission, which launched in December 2013 and became the first time a Falcon 9 rocket sent a payload into geostationary transfer orbit. "That was a huge marker of credibility and validation for SpaceX," Ellis said.

Of course, Relativity doesn't have its Terran 1 rocket flying yet—when SpaceX made that 2011 announcement the company had already performed two successful test flights of the Falcon 9. Ellis said development of the Terran 1 rocket continues on schedule, with plans to conduct its first orbital test launch at the end of 2020. The company continues to grow, too, with a staff of 80 now. They will have plenty of work to do over the next 18 months to reach the company's Florida launch pad.