A Washington state startup achieved a milestone last weekend toward what its founders call the “holy grail” of a fully reusable commercial space rocket. Suburban Seattle-based Stoke Space successfully flight tested the reusable upper stage of its rocket prototype.
The vertical launch followed by a hover and then an upright landing next to the launch pad happened at Grant County International Airport in Moses Lake, Washington. The test flight lasted less than half a minute.
"It was a relatively small, low-altitude flight -- only 30 feet high,” said Stoke Space co-founder and CEO Andy Lapsa. “But… it was a huge success and we're all pretty excited."
Stoke Space is a four-year-old startup that is pursuing the goal of building fully reusable two-stage cargo rockets with rapid turnaround capability. Such an achievement promises to dramatically lower the cost of launching satellites and commercializing space.
“It was absolutely incredible to watch it rise off the ground,” said Moses Lake airport director Rich Mueller, who observed from about one-quarter mile away. “It was surprisingly quiet. It looked totally weightless. There was no shaking.”
“It was probably the most exciting thing I've seen in my 14 years with the Port of Moses Lake,” Mueller said, who's witnessed his fair share of military stunts and airplane first flights.
— Stoke Space (@stoke_space) September 18, 2023
Few outsiders knew about the rocket test in advance, so Mueller said the fiery event did not attract spectators from surrounding communities to the airfield on a calm Sunday morning. The liquid hydrogen-powered test vehicle looked more like a big, shiny flying tea kettle than a slender and tall space rocket. For the short “hop,” it flew without a nose cone and the payload compartment to come.
Stoke Space has rivals in the race to design a 100% rapidly reusable launch vehicle. Current market leader SpaceX, owned by billionaire Elon Musk, is designing its new heavy-lift Starship rocket to be fully reusable. SpaceX’s current workhorse rocket – the Falcon 9 – has a reusable first stage, but the second stages burn up upon reentry into Earth’s atmosphere.
Other U.S. commercial launch startups, such as Relativity Space, and the Chinese space agency are designing fully reusable medium or heavy-lift rockets to achieve cheaper and quicker trips to orbit. Stoke Space was founded by two engineers formerly with billionaire Jeff Bezos’ rocket firm Blue Origin, which also has experience with reusable launch vehicles.
SpaceX has demonstrated the practicality of recycling the first-stage booster of a commercial space rocket more than 200 times since 2015. But making the second stage reusable is a much harder problem to solve because of conflicting demands. On the one hand, there is pressure to keep the space vehicle lightweight to maximize payload capacity. But to survive reentry into the atmosphere the upper part of a reusable rocket has to have a robust heat shield, plus additional fuel for maneuvering to a precision landing, ideally.
Lapsa said Sunday’s flight test of the “Hopper2” second-stage prototype “proved out all of the really new and novel technology elements that go into our vehicle. So, things like our actively-cooled heat shield.”
He said Stoke Space would next pivot to designing its first-stage booster and was pushing hard to get a complete rocket into orbit by 2025. The startup has attracted tens of millions of dollars in venture capital investment led by Bill Gates’ Breakthrough Energy Ventures.
Stoke Space has secured a launch pad at Cape Canaveral in Florida for future high-altitude flight tests and commercial launches. Lapsa said he expects to continue rocket engine testing on the ground, known as static tests, at the company’s rural Moses Lake facility, which is about three hours east of company headquarters. Launching to space from Moses Lake is not feasible because there are homes under the flight path in all directions.
Sunday’s low-altitude hop by the rocket stage prototype necessitated the temporary closure of one smaller runway at Grant County International Airport closest to the flight test. The rest of the airport, which has five runways in all, stayed open. It wasn’t very busy at the time, Mueller said.
Mueller said he was reminded of a time in Moses Lake’s history nearly 25 years ago when the port district had aspirations to host launches and landings for a next-generation space shuttle pitched by NASA contractor Lockheed Martin. The Spaceport Washington idea faded when the NASA-Lockheed Martin venture didn’t come to fruition.
“It couldn’t help thinking back to that on Sunday,” Mueller said. “Maybe they were ahead of their time. But here we are, we’re having space activity.”