Stoke Space
Stoke Space has offered only a few hints about the design of a fully reusable launch vehicle, whose development starts with work on an upper stage. Credit: Stoke Space

PARIS — Stoke Space raised $65 million in a Series A round announced Dec. 15, funding development and testing of the upper stage of a reusable launch vehicle.

The company, based in the Seattle suburb of Kent, Washington, said Breakthrough Energy Ventures led the round. Several other new investors also joined the round, including Spark Capital, Point72 Ventures, Toyota Ventures, Alameda Research and Global Founders Capital. Several investors in the company’s $9.1 million seed round, announced in February, participated as well.

Stoke announced earlier this year its intent to create a fully reusable launch vehicle, starting with the second stage. This round, the company said, will allow it to complete development of a prototype of that stage and conduct a series of flight tests starting at the end of 2022.

Those tests will start as low-altitude vertical takeoff and landing tests, said Andy Lapsa, co-founder and chief executive of Stoke, in an interview, moving progressively toward higher-altitude tests. The first flights will be at the company’s test site in Moses Lake, Washington, although he said high-altitude flights may need to take place elsewhere.

“We’re not going to go to super high altitudes right off the bat, but it’s certainly in our test plan,” he said. “There’s some good objectives from the low-altitude testing, from GNC and controls to having a functioning rocket engine.”

The company hasn’t disclosed many details about its vehicle concepts or key technologies. He did say the vehicle won’t use “brittle ceramic tiles” for thermal protection, since they don’t meet their requirements for a system that can be turned around rapidly with minimal inspections. “Solving that problem was the crux of our early days, and, frankly, if we didn’t come up with something that we thought was executable, we probably wouldn’t have started the company.”

The vehicle does feature an engine that looks “very different from conventional engines,” Lapsa said, but didn’t reveal design details. That design will enable it to operate both at low altitudes and in vacuum. “It’ll be by far the highest performing rocket engine for any of the small launchers.”

Stoke previously won Small Business Innovation Research awards from NASA and the National Science Foundation for a “novel rocket engine configuration” intended for upper stages and planetary landers, as well as an “integrated propulsion solution to enable reusable upper stages.”

Stoke started the year with five employees and has now grown to 29. Lapsa said the company intends to hire more people, although not at a fast rate. “We’re not going to build an entire rocket and all the infrastructure behind it with 29 people. But, that being said, it’s not going to be hundreds of people within the next phase here.”

He said the company went with Breakthrough Energy Ventures because they had similar viewpoints. “Our goal for this round was to find investors who are long-term thinkers, who are looking at frontier tech and hardware manufacturing. It’s kind of our founding objective to use space for making life on Earth better, more scalable and sustainable,” he said. “It turns out they had developed a similar thesis on space, and that is a major vertical that’s needed to make the world more environmentally sustainable.”

Breakthrough Energy Ventures, part of the Breakthrough Energy organization founded by Bill Gates in 2015 to support development of technologies for net-zero emissions, said in a statement that space is critical to understanding climate change.

“We see two main barriers for such innovation in space: high cost and lack of launch availability,” said Carmichael Roberts, colead of the investment committee of Breakthrough Energy Ventures, in that statement. “However, Stoke’s unique vehicle design and operational capabilities provide a path to achieving ultra-low-cost, fast-turnaround launch for dedicated orbital delivery.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...