Inside The Startup Building Reusable Rockets

Tom says Stoke is building rockets designed to travel to space and return, with the aim of lowering cost and improving availability and reliability. He says roughly 150 commercial launches a year leave limited room for customers, and that cost and availability constrain new space applications.

Nova is a two-stage rocket: its first stage returns to land, while its second stage, Andromeda, is designed to survive re-entry and be reused. Tom describes a heat shield that circulates cold liquid hydrogen through a heat exchanger, plus 24 thrusters to help the capsule slow down and land at the right angle. He says upper stages face re-entry speeds around 17,000 miles per hour and temperatures above 2,700 degrees Fahrenheit.

Tom says he grew up launching model rockets and chose propulsion as an engineer. He and Andy left Blue Origin to start Stoke in 2019, giving themselves six months to find traction. They built an early thruster test setup in a shipping container; Tom welded the structure while Andy worked on the company pitch.

Tom says the founders underestimated fundraising, especially as COVID disrupted the market, and turned to YC for help with investor introductions and the process. He says Stoke has raised about $990 million and built a 168,000-square-foot factory designed for roughly seven vehicles a year. Making rocket parts in-house lets the team move from a month-long test and repair cycle to a day or two, he says.

Stoke built an operations tool called Bolt Line to track vehicle parts, service life, and maintenance as it aims to reuse vehicles across flights. The team is also testing engines, structures, avionics, and flight software, while constructing a launch site at Complex 14 in Cape Canaveral. Tom says the goal is to fly frequently and that the idea was worth trying even before success was certain.