Most investors demand a pitch deck, a formal board presentation, and several rounds of due diligence before they agree to write a check. Former “Shark Tank” investor Mark Cuban took a different approach, and it started with a cold email he received in Dallas from a young engineer who wanted to build rockets.
Cuban committed $500,000 to that stranger’s company, Relativity Space, without a single phone call or face-to-face meeting, and the two have still never met.
That bet has ballooned into a stake in a company last publicly valued at $4.2 billion in its 2021 Series E, with launch contracts from NASA and the U.S. Space Force.
Cuban wired $500,000 to Relativity Space after a cold email
Cuban shared the story during a September 2024 episode of comedian Theo Von’s podcast “This Past Weekend,” describing how Ellis and his friends emailed him from Dallas proposing a space startup.
Cuban admitted he had no knowledge of the aerospace sector, but something about the founders’ ambition convinced him to take the risk anyway. “I don’t know s**it about space, but I’ll get you started and see what happens,” Cuban recalled telling them, Fortune reported.
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Ellis had previously worked at Blue Origin, the rocket company founded by Jeff Bezos, where he was credited with bringing metal 3D printing in-house.
Cuban was quick to credit the founders rather than himself, noting that his only real contribution was providing the initial funding to get the venture moving.
“And they’ve to their credit, right? It’s not like I helped them get there, right? The guys were just insanely smart and good. Right. I got lucky, you know? … But, like, helping them have some. … Yeah, I just got him started,” Cuban said during the Von interview.
Relativity’s 3D printing strategy has shifted under new leadership
The company initially built its strategy around massive 3D printers, though under Schmidt, it has scaled back full-rocket additive manufacturing in favor of a mixed approach that outsources select structural components while keeping 3D printing for engines and key parts, the Washington Post reported.
Relativity is developing the Terran R, a two-stage, reusable rocket with first-stage downrange landing.
The rocket, capable of carrying up to 23,500 kilograms to low Earth orbit in its reusable configuration, aims to compete directly with SpaceX’s Falcon 9. Relativity Space Chief Revenue Officer Josh Brost said it’s designed “for the sweet spot of the market in medium-to-heavy lift launch,” according to a company press release.
Our payload capacity is large enough to provide great economics on a dollar-per-satellite basis but small enough to ensure we’re filling it for each launch.
The first launch is planned for late 2026 from Launch Complex 16 at Cape Canaveral, Florida, the company confirmed in the press release.
Relativity went through a significant leadership transition after experiencing cash-flow difficulties in late 2024, threatening the company’s ability to reach the launchpad, The New York Times reported.
Former Google CEO Eric Schmidt stepped in as Relativity’s CEO in March 2025, making a large personal investment and acquiring a controlling interest, The Times reported.
Tim Ellis, the co-founder who originally emailed Cuban, stepped away from the top job but remains on the company’s board of directors.
The Washington Post/Getty Images
Relativity stacks $2.9 billion in launch contracts from NASA and military clients
Relativity has assembled more than $2.9 billion in launch service agreements for Terran R from a client list that includes NASA, the U.S. Space Force, SES, Intelsat, and OneWeb, TSG Invest reported.
That order backlog reflects broad demand for a credible alternative to SpaceX, which controls the vast majority of the American commercial launch services market.
The backlog “shows how desperate the market is for another cost-effective launch services provider,” given SpaceX’s dominant position, Brost told SpaceNews.
Cuban summed up the competitive dynamic on the Von podcast in three words: “Coming for you, Elon.”
SpaceX IPO filing adds competitive pressure across launch sector
SpaceX publicly released its S-1 prospectus with the Securities and Exchange Commission on May 20, 2026, after confidentially filing in April, and is expected to begin trading on the Nasdaq under the ticker SPCX around June 12, 2026.
The company is currently targeting a $1.75 trillion valuation, down from an earlier $2 trillion goal. SpaceX is pricing shares at $135 to raise about $75 billion in what would become the largest stock market debut in history, Reuters reported.
The broader space economy is projected to grow from $630 billion in 2023 to $1.8 trillion by 2035, according to a World Economic Forum and McKinsey & Company report.
For Relativity and other SpaceX competitors, the IPO could reshape the competitive landscape by giving SpaceX access to unprecedented levels of public market capital.
Cuban built a billion-dollar career on instinct and cold emails
The Relativity investment fits a broader pattern in Cuban’s career, where the billionaire has repeatedly committed large sums of money with limited traditional due diligence.
He once bought a 24,000-square-foot Dallas mansion sight unseen for around $12 million, roughly half its $25 million construction cost, basing his decision entirely on photographs, he told GQ in a 2022 interview.
Cuban’s net worth now stands at an estimated $10.3 billion, Bloomberg’s Billionaires Index reported.
He built his initial fortune by selling Broadcast.com to Yahoo for $5.7 billion in 1999, and he later turned a $285 million purchase of the Dallas Mavericks into a multibillion-dollar return after selling his majority stake, according to Fortune.
His most visible recent venture is Cost Plus Drugs, the generic-pharmacy company he co-founded in 2022 with a mission to offer prescription medications at significantly lower prices.
On the Von podcast, Cuban credited his open inbox with the Relativity opportunity, saying that making himself available opened the door.
The same instinct that drove the Broadcast.com sale, the Mavericks purchase, and the Cost Plus Drugs launch produced a stake in one of the few rocket startups now positioned to challenge SpaceX directly.
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