Relativity is 3D printing rockets and raising billions. Will its technology work?

Tim Ellis, an unassuming 31-year-old with glasses who shuffles around his sprawling rocket factory in designer sneakers, has what every space company founder longs for: a seemingly endless well of investors willing to pour money into his company.

Relativity Space, the rocket startup Ellis co-founded in 2015 after he left Jeff Bezos' space company, plans to build fairly small rockets that can blast satellites into orbit cheaply and quickly. If that sounds familiar, that's because it's the same business plan touted by dozens of rocket startups all over the world.

Relativity stands out in some respects. The company raised about $1.2 billion in just eight months, a level of investment frenzy enjoyed by few in the space industry outside of Elon Musk's SpaceX. Relativity's massive factory in Long Beach, California, teems with activity as rocket parts are hauled from one area to another, workers compete for oversubscribed desk space, and massive hangar doors conceal some of the largest 3D printers in the world at work.