A four-year-old Seattle-area startup called Stoke Space executed a successful up-and-down test of its “Hopper” developmental rocket vehicle today, marking a major milestone in its quest to create a fully reusable launch system.
Hopper2’s 15-second flight took place at Stoke’s test facility at Grant County International Airport in Moses Lake, Wash. A hydrogen-fueled rocket engine sent the test vehicle up to a height of 30 feet, with a landing 15 feet away from the launch pad, Stoke CEO Andy Lapsa told GeekWire.
“It’s the last test in our development program for Hopper, and by all accounts, it’s been very successful,” Lapsa said.
Today’s test follows up on work that was done this spring with an earlier prototype, Hopper1, and a static engine firing for Hopper2 that was conducted this month.
In a Sept. 12 posting to X / Twitter, Stoke Space said “we’ve now learned everything we were looking for from this dev test vehicle in order to finalize the orbital design … but HELL YES we’re gonna hop it for icing on the cake.”
“This Hopper program was really geared to develop the reusable second-stage system, and specifically prove out a lot of the new and novel technology elements that go into it,” Lapsa explained today. “There’s the actively cooled, regeneratively cooled heat shield. We have a very unique rocket engine … with a single set of turbo machinery that feeds an array of thrusters. Both of those two, the heat shield and the engine, are coupled.”
Lapsa said Stoke Space’s rocket may well mark the first use of differential-thrust vector control for attitude control since 1972, when that approach was used for the last Soviet N1 moon rocket.
In addition to testing out the technical innovations, Stoke’s team also had to go through a steep learning curve on launch logistics. “We’re a young company, so developing operational procedures, ground support equipment, guidance, navigation and control, flight software, flight computers, comms — all of these things are new,” Lapsa said. “We have a very experienced team, but this is the first time that we’ve been doing all those things as a Stoke team.”
Stoke Space was founded in 2019 by Lapsa, a veteran of Jeff Bezos’ Blue Origin space venture; and Tom Feldman, who worked at Blue Origin after interning at SpaceX. In addition to the testing grounds at Moses Lake’s airport, the company has a 21,000-square-foot engineering and manufacturing headquarters in Kent, Wash., not far from Blue Origin’s HQ.
In 2021, the company raised $65 million in a funding round led by Microsoft co-founder Bill Gates’ Breakthrough Energy Ventures. And earlier this year, Stoke won the go-ahead to take over Cape Canaveral Space Force Station’s Launch Complex 14 in Florida, the site of John Glenn’s history-making Mercury launch in 1962.
Going forward, Stoke’s team will concentrate more fully on developing its rocket’s first stage and ramping up operations in Florida, Lapsa said.
“The focus is now very centrally on getting to orbit, and the first stage is the most critical part of that,” he said. “We’ll be focusing on first-stage engine development. I would say it’s a custom-designed engine, but in terms of novelty and world-first, it’s not intended to be one of those.”
Eventually, Stoke plans to offer a fully reusable launch system, including a second stage that can be brought back to Earth without having to rely on exotic shielding.
The concept behind Stoke Space’s launch system has been compared to the much larger two-stage Starship system that’s being developed by SpaceX for trips beyond Earth orbit. You can extend that comparison to characterize today’s Hopper flight as a parallel to SpaceX’s Grasshopper test flights in 2012 and 2013, or the Starhopper tests in 2019.
Lapsa said he was “incredibly proud” of his team.
“The team is unbelievable, and you know, we’ve developed everything. Two and a half years ago, this spot in Moses Lake was a blank desert. Today we’ve launched a brand-new hydrogen-oxygen engine — and it’s a very unique engine — on a vehicle that took off and landed vertically,” he said. “I think everybody’s on cloud nine.”