Jeff Bezos visited the new headquarters of Relativity Space, the 3D-printing rocket builder

The founders of two private rocket-building companies met today – one, the richest person on Earth; the other, leader of a venture pushing the boundaries of manufacturing.

Jeff Bezos stopped by the gleaming new “factory of the future” of Relativity Space on Friday, a person familiar with the visit told CNBC, for a tour of the Long Beach, California facility with CEO Tim Ellis. Relativity moved into the new facility last summer from its prior headquarters in Inglewood.

The nature of the visit to Relativity’s headquarters was unclear.

Ellis previously worked at Bezos’ space company Blue Origin as a propulsion engineer – and was credited for bringing the process of 3D printing metal rocket parts in-house. Ellis then left Blue Origin in 2015 to found Relativity with Jordan Noone, a college classmate and former SpaceX propulsion engineer.

Relativity declined CNBC’s request for comment on Bezos’ visit, while Blue Origin did not respond to requests for comment.

Relativity has gone all in on the 3D-printing approach, using enormous printers and metallurgy developed in-house to build 95% of the parts of its rockets. Ellis emphasizes that 3D-printing drastically cuts down on the complexity of its rockets, but also makes them faster to build and modify. Eventually, Relativity says its simpler process will be able to turn raw materials into a rocket on the launchpad in under 60 days.

The company’s first rocket, Terran 1, is expected to launch for the first time later this year. Terran 1 is priced at $12 million per launch and is designed to carry about 1,250 kilograms to low Earth orbit. That puts Terran 1 in the “medium lift” section of the U.S. launch market, between Rocket Lab’s Electron and SpaceX’s Falcon 9 in both price and capability.

Relativity is also working on a second, larger rocket called Terran R – aiming to compete with SpaceX’s Falcon 9 rocket in both launch capability and reusability. Terran R is the first of several new initiatives that Ellis expects Relativity to unveil in the year ahead, with the company having raised more than $680 million since its founding five years ago.