Seven years ago, Tim Ellis sent Mark Cuban a life-changing cold email.
Ellis was an engineer at Jeff Bezos' space startup, Blue Origin, and he dreamed of launching his own rival company. His cold email to Cuban was an investment pitch that called space "sexy" and teased the idea of 3D printing an entire rocket.
The pitch worked – almost immediately. "A few minutes after cold emailing Mark Cuban, we had a half a million dollar commitment," Ellis, 31, tells CNBC Make It.
Today, Ellis is the co-founder and CEO of Los Angeles-based Relativity Space, which is months away from launching the world's first 3D-printed rocket into space. Along the way, Ellis and his co-founder Jordan Noone – who interned with Ellis at Blue Origin before landing an engineering job at SpaceX – have raised more than $1.3 billion from investors like BlackRock and Tiger Global.
That money has given Relativity Space a valuation of $4.2 billion, while funding its mission of 3D-printing rockets to compete in a private aerospace industry expected to be worth well over $1 trillion by the end of the decade.
Ellis' penchant for rockets started early: After studying at the University of Southern California's Rocket Propulsion Lab and landing summer internships at Blue Origin for three consecutive years, Ellis landed a full-time engineering job at Bezos' company.
At Blue Origin, Ellis 3D-printed individual rocket parts, and became fascinated by the idea of using mega-sized 3D printers to create entire rockets. It could reduce costs, he reasoned, and potentially even pave the way for the sort of multiplanetary society that SpaceX CEO Elon Musk has often discussed.
"I realized, for that future to exist, someone was going to have to found a company somewhere that built an industrial base on Mars," says Ellis. "You need a small, lightweight factory that you can launch on a rocket to another planet that can build a wide range of products with very little human involvement."
Ellis figured that someone might as well be him. He and Noone say they've built the world's largest metal 3D printer, the 24-foot-tall Stargate — and used it to build their first 3D-printed rocket, called the Terran 1. Last month, Ellis told Florida Today that the Terran 1 is on track to launch from the Cape Canaveral Space Force Station for its first space flight later this year.
"I'm now realizing a lot of the things that I got made fun of for [while] growing up – whether it was researching every topic under the sun, and following all of these threads, and being hyper-curious, and pattern-matching information – all of those skills have let me scale and run Relativity," Ellis says.
To learn how Ellis built Relativity Space into a $4.2 billion company competing with the likes of Jeff Bezos and Elon Musk, watch the video above.