Stoke Space: Forging a New Path to Full Reusability

The 151st Rocket Company

When aerospace engineers Andy Lapsa and Tom Feldman founded Stoke Space in 2019, the commercial space industry was in the midst of a historic boom. By their own count, there were already something like 150 rocket startups competing for venture capital and satellite contracts. On the surface, the last thing the world seemed to need was company number 151.

But Lapsa and Feldman, veterans of the industry’s most advanced propulsion labs, saw a fundamental flaw in the market. The revolution started by SpaceX with its reusable Falcon 9 booster was incomplete. While the industry had become fixated on landing first-stage boosters, every other company was, at best, trying to replicate that one trick. This approach, in Stoke’s view, was a dead end. Partial reusability was just a stepping stone, not the destination.

The real bottleneck, the industry’s expensive secret, was the expendable second stage.

In a typical satellite launch, the first-stage booster does the initial heavy lifting, pushing the vehicle to the edge of the atmosphere before separating and returning to Earth. The second stage then ignites, accelerating the payload to orbital velocity – speeds in excess of 17,000 miles per hour. This second stage is a complex, high-performance machine, complete with its own sophisticated rocket engines, flight computers (avionics), propellant tanks, and navigation systems. It’s a machine that costs millions of dollars to design, build, and test. And at the end of every single mission, it is thrown away, either burning up in the atmosphere or being abandoned in orbit as space junk.

This practice is the single greatest limiter on both launch cost and launch frequency. For satellite constellation operators, launch still represents 30% to 70% of their total deployment cost. As long as companies are forced to build and discard a new multi-million-dollar rocket engine and vehicle for every satellite they put in orbit, the dream of truly low-cost, “aircraft-like” access to space remains impossible.

There was also a reliability paradox. The founders at Stoke analyzed the launch data and found a telling pattern. In a long series of recent Falcon 9 launches, the few failures that occurred were all traced back to the disposable second stage – the one part of the rocket that was brand new on every flight. The “flight-proven,” reusable first stage, which had flown and landed multiple times, had a perfect record of success in that same span. The data suggested a powerful conclusion: full reusability, where every component of the launch vehicle is flight-proven, would lead to a dramatically more reliable and safer system.

Stoke was founded to solve this problem. It wasn’t created to be just another launch company; it was created with the “end game in mind” from day one. Its mission was to build the world’s first 100% fully and rapidly reusable rocket. They weren’t just iterating on the status quo; they were building a direct critique of it, tackling the one, impossibly hard piece of the puzzle that everyone else was avoiding.

The Founders: A Vision from Inside the Industry

Stoke’s conviction to solve this problem came from a place of deep technical expertise. The company wasn’t founded by software billionaires or venture capitalists; it was founded by two of the propulsion engineers who had been building the engines for the first generation of reusable rockets. They had spent their careers on the inside, staring at the physics, and they believed they had a unique solution.

Andy Lapsa, the company’s CEO, holds a PhD in Aerospace Engineering from the University of Michigan and a BS from Cornell. His career led him to Blue Origin, where he became a central figure in the company’s propulsion division. He rose to become the Director of BE-3 and BE-3U Engines. The BE-3 is the liquid hydrogen-fueled engine that powers the New Shepard rocket on its suborbital flights. This role gave Lapsa world-class, hands-on expertise in the most finicky, high-performance propellant in rocketry: liquid hydrogen. He also played a lead role in developing the company’s powerful BE-4 methane engine. At Stoke, Lapsa serves as the business-facing co-founder, responsible for guiding the company’s strategy and, most importantly, raising the significant capital required to build a new rocket from scratch.

Tom Feldman, Stoke’s Chief Technology Officer, holds both a Master’s and a Bachelor’s degree in Aerospace Engineering from Purdue University. He is also a Blue Origin veteran, where he served as a Senior Propulsion Design Engineer working on key components for the BE-4 engine, including its oxidizer boost pump and thrust chamber. Before his time at Blue, Feldman also held positions at SpaceX. This combined experience gave him a rare, first-hand perspective on the design philosophies of the two leading reusable rocket companies in the world. As CTO, Feldman is the technical-focused leader, with a self-described job of gathering information and helping the team make smart, technically-sound choices.

The background of the founders is the key to understanding Stoke’s entire technological approach. Both Lapsa and Feldman are, at their core, engine experts. Lapsa’s specific, deep knowledge of liquid hydrogen propulsion from his work on the BE-3 is not a coincidence. Stoke’s entire solution to the “unsolvable” problem of second-stage reusability is not a structural one, but a propulsion-based one. They didn’t design a vehicle and then look for an engine. They started from their first-principles understanding of thermodynamics, fluid dynamics, and advanced rocket propulsion and designed a novel, integrated vehicle around a unique propulsion cycle. Their background is the company’s core technology.

Assembling the Team

While Lapsa and Feldman provide the technical vision, they have systematically built a corporate structure around them that signals a high-level of industrial and strategic maturity. This is not a research project; it’s a serious operational and defense-focused company.

The executive leadership team includes experienced operators like Kelly Hennig as Chief Operating Officer and Paul Croci as Chief Financial Officer. This team is capable of managing the complex day-to-day logistics of manufacturing and finance, freeing the founders to focus on technology and strategy.

The company’s Board of Directors and advisors, in particular, demonstrate Stoke’s strategic positioning. The board includes Lieutenant General John Shaw (Retired), the former Deputy Commander of U.S. Space Command. His presence provides an invaluable, direct line of insight into the needs of the U.S. Department of Defense and has been instrumental in aligning Stoke’s vehicle with national security priorities. The board also features Steve Angel, the Chairman and former CEO of Linde. Linde is one of the world’s largest suppliers of industrial gases, including the liquid hydrogen and liquid oxygen that Stoke’s rocket runs on. This high-level connection to a key part of the supply chain is a powerful strategic advantage.

The list of advisors includes industry “legends.” The most notable is Hans Koenigsmann, SpaceX’s fourth-ever employee and its former Vice President of Build and Flight Reliability. Koenigsmann was the technical authority who oversaw the development and operational success of the Falcon 9, arguably the most reliable rocket in history. His decision to advise Stoke lends immense practical and reliability-focused credibility to their design. He is joined by other key figures like Robb Kulin, a former SpaceX Chief Engineer and COO of Firefly Aerospace, and Caryn Schenewerk, a leading expert in space law and policy.

This carefully assembled team of NewSpace veterans, high-level defense leadership, and legacy industry titans shows that Stoke is building not just a novel rocket, but a robust, long-term industrial and defense company.

Nova: A Different Kind of Reusable Rocket

The vehicle at the center of this effort is named “Nova.” It is a two-stage, medium-lift rocket designed from its very first sketch for 100% full and rapid reusability.

From the outside, it has a familiar rocket shape, standing approximately 40.2 meters (132 feet) tall with a diameter of 4.2 meters (14 feet). These specifications have been deliberately chosen. Stoke is not trying to build a small satellite launcher, a market that is heavily oversaturated, nor is it attempting the monumental (and colossally expensive) task of building a super-heavy-lift vehicle like SpaceX’s Starship.

Instead, Stoke is targeting the “Goldilocks” zone: the medium-lift class. This is the commercial and government sweet spot, perfectly sized for the primary business of the modern space economy: deploying large satellite constellations into low-Earth orbit. The Nova rocket is a direct, head-on competitor to the workhorse Falcon 9 and the in-development Rocket Lab Neutron.

While the vehicle’s payload specifications have naturally evolved during the design and testing process, the company’s published figures are specific. In its fully reusable configuration – where both the first and second stages return for landing – Nova is designed to deliver 3,000 kg (over 6,600 lbs) to low-Earth orbit. This is its baseline mission. The vehicle also has a “max payload” capacity of 7,000 kg (over 15,400 lbs), which would likely involve expending the second stage or having the booster land downrange on a barge. It is also designed to deliver 2,500 kg to higher-energy orbits, such as a geostationary transfer orbit (GTO).

The Workhorse: Nova’s First Stage

Nova’s first stage, or booster, is the workhorse of the launch system. It’s designed for maximum robustness, reliability, and rapid turnaround. Like the Falcon 9, it is designed to fly back to the launch site and perform a powered vertical landing, ready to be refueled and reflown. But while the function is similar, the technology powering it is a generation ahead.

Zenith: The Power of Full-Flow

The booster is powered by seven “Zenith” engines, each designed and manufactured in-house by Stoke. Every Zenith engine is capable of producing over 100,000 pounds of thrust. These engines are not simple. They employ a full-flow staged combustion (FFSC) cycle, which is widely considered the pinnacle of rocket propulsion technology.

This design is incredibly complex and difficult to master, but it offers enormous benefits for performance and reusability.

In a typical rocket engine, only a small portion of the fuel or oxidizer is sent through a “preburner” to create gas, which then spins a turbine to power the main propellant pumps. It’s an efficient but imperfect system. In a full-flow staged combustion engine, all of the fuel and all of the oxidizer are sent through separate preburners. The fuel-rich gas spins the turbine for the fuel pump, and the oxidizer-rich gas spins the turbine for the oxidizer pump.

This “gas-gas” process, where both propellants are fully gasified before they meet in the main combustion chamber, results in a more complete and efficient mixing and combustion. This allows the engine to run at extremely high pressures in the main chamber, generating more thrust for the same amount of propellant.

The main advantage for Stoke is reusability. Because 100% of the propellant is flowing through the turbines (not just a small fraction), the turbines can spin at full power while running at significantly cooler temperatures and lower pressures. A turbine that isn’t subjected to extreme heat and pressure is under far less stress. Less stress means it doesn’t degrade, allowing for a much longer service life, higher reliability, and the confidence to fly it again and again with minimal inspection. It’s the difference between an engine screaming at its redline and a high-torque engine loping along at an easy, sustainable pace.

This technology is so difficult that for decades, it was considered impractical. Today, only two companies in the world have successfully built and hotfired their own FFSC engines: SpaceX, with its Raptor engine for Starship, and Stoke, with its Zenith engine for Nova. Stoke’s team, leveraging its founders’ deep expertise, managed to design, build, and successfully test this engine in just 18 months, a testament to their rapid development-and-test model.

Methane as a 21st-Century Fuel

The Zenith engines run on methalox: liquid methane (LNG, or liquefied natural gas) and liquid oxygen (LOX). This was a deliberate and pragmatic choice for the first stage, balancing three key factors.

First, and most importantly for reusability, methane burns clean. The rocket-grade kerosene (RP-1) used by rockets like the Falcon 9 and Soyuz is a complex hydrocarbon that, when burned, leaves behind a sooty, oily residue known as “coking.” This gunk gets into the engine’s turbines, injectors, and plumbing, and must be extensively cleaned and refurbished between flights – a time-consuming and costly process. Methane, a much simpler molecule, burns almost completely, leaving virtually no residue. This is a non-negotiable requirement for a rocket designed to be turned around in 24 hours.

Second, methalox is a “Goldilocks” propellant. It’s more efficient and delivers higher performance than kerosene, but it is dramatically cheaper and easier to source and handle than liquid hydrogen, which is reserved for the upper stage.

Third, as LNG, it’s a readily available commercial fuel. This combination of clean-burning reusability, high performance, and low operational cost makes it the ideal, pragmatic choice for the booster stage, which does the brute-force work of lifting the vehicle off the ground.

The Crown Jewel: The Reusable Second Stage

If the first stage is an advanced workhorse, the second stage is Stoke’s crown jewel. This is the piece of technology that makes Stoke “company number 151,” and it is their answer to the “holy grail” of rocketry: building an upper stage that can return from orbit and land, ready to fly again.

The problem is the heat. A second stage travels to orbital velocity, over 17,000 mph. When it re-enters the atmosphere, it slams into the air with exponentially more kinetic energy than the first stage, generating temperatures of thousands of degrees that can melt any known structural metal.

Historically, spacecraft have used two solutions to this problem, and both are flawed for a system that needs to be rapidly reusable. The first is an “ablative” heat shield, like those on the Apollo capsules. These shields are designed to char, melt, and burn away, carrying the heat with them. They work perfectly, but only once, as they are destroyed in the process.

The second solution is a passive thermal protection system, most famously the ceramic tiles used on the Space Shuttle. These tiles are incredibly delicate, brittle, and susceptible to damage from launch debris, rain, or even handling. After every flight, the Shuttle’s tiles required thousands of person-hours of painstaking inspection, repair, and replacement. This operational nightmare was a primary driver of the Shuttle’s high costs and slow, months-long turnaround time. SpaceX’s Starship is attempting a modern version of this tile-based system, betting that it can mass-produce tiles so cheaply that the inspection and replacement burden becomes manageable.

Stoke looked at this history and chose a third, radically different path: an active thermal protection system.

An Engine Built for Two Jobs

The innovation begins with the second stage’s engine, named “Andromeda.” It’s not a single, large engine bell. Instead, Andromeda is a unique architecture composed of a ring of thrusters integrated directly into the circular base of the vehicle.

This design has evolved as Stoke has tested and iterated. The first version, “Andromeda 1,” was used on the company’s “Hopper” test vehicle. It featured a ring of 30 individual thruster chambers. The newer “Andromeda 2,” the flight-intent version, has been optimized. The number of thrusters was reduced to 24, but each individual thruster is larger. This change simplifies the complex internal plumbing, reduces the total number of parts, and saves weight, all while maintaining the engine’s performance and unique steering capabilities.

This ring architecture is key because it allows the engine to perform two distinct jobs.

1. In-Space Propulsion: In the vacuum of space, the exhaust plumes from the 24 thrusters expand and merge, creating an “aerospike-like” effect. This phenomenon allows the ring to function as a single, large, and highly efficient engine, giving it the high performance it needs to deliver payloads to precise orbits.
2. Steering and Landing: The Andromeda engine completely eliminates the need for heavy, complex hydraulic gimbals that physically “steer” a normal rocket engine. Instead, the vehicle steers using differential throttling. To turn the rocket left, the flight computer simply commands the thrusters on the left side of the ring to fire at a slightly lower power level than the thrusters on the right. This precise, instantaneous control provides all the steering the vehicle needs for both orbital maneuvers and a soft, propulsive landing.

The Heat Shield That ‘Sweats’

The ring of thrusters on the Andromeda engine is built around Stoke’s single greatest innovation: a metallic, actively cooled heat shield.

The simplest way to understand this system is to think about the human body. When your body overheats during exercise, your circulatory system pumps a coolant (blood) to your skin, which then sweats, and the evaporation of that sweat cools you down. Stoke’s heat shield does the same thing, but with liquid hydrogen.

Here is how it works:

1. Durable Metal: The heat shield itself is built from a robust, ductile metal, not fragile ceramic tiles. It is designed to be tough, resilient to damage, and capable of flying again and again.
2. Internal Channels: This metal shield is not solid. It’s built with a network of tiny, intricate channels running just beneath its surface, much like a car’s radiator or the circulatory system under your skin.
3. Active Cooling: During the fiery inferno of atmospheric reentry, the vehicle’s flight computer uses the same pumps and propellant tanks for its engine to pump its own ultra-cold liquid hydrogen fuel (stored at a frigid -423°F, or -253°C) from the main tanks and circulates it through these tiny channels in the heat shield.
4. The “Heat Sponge”: This cryo-cold hydrogen acts as a massive “heat sponge.” It absorbs the thousands of degrees of reentry energy, wicking it away from the metal shield and preventing it from melting.

The true elegance of the design is that the heat isn’t just absorbed and wasted. The system is regenerative. The immense heat absorbed by the liquid hydrogen causes it to flash into a hot, high-pressure gas. This gas, which is now full of captured thermal energy, is then used. It’s channeled directly to the engine’s turbopumps, spinning the turbines that power the entire system.

This creates a beautiful, self-regulating feedback loop. The hotter the reentry, the more heat the hydrogen absorbs. The more heat it absorbs, the more high-pressure gas it creates. The more gas it creates, the faster it spins the turbopumps. The faster the pumps spin, the more cold hydrogen they pump to the heat shield, which cools it down.

This integrated system – where the engine is the heat shield and the heat shield is the engine – is designed to be robust, resilient to damage, and operate with passive failure modes. It can survive the most extreme reentry environments and be ready to fly again in hours, not months.

Why Hydrogen? The Dual-Purpose Propellant

This brings up a key question: why does the Nova rocket use two different types of fuel? Methane for the first stage, and hydrogen for the second. This “split-propellant” strategy adds operational complexity at the launch pad, so there must be a compelling reason for it.

The reason is that Stoke’s entire reusable upper stage design is only possible with liquid hydrogen. The propellant is the system.

Reason 1: Performance. Liquid hydrogen and liquid oxygen (hydrolox) is, by a wide margin, the most efficient, high-performance chemical rocket fuel combination. It has the highest “specific impulse” (Isp), which is the rocket-science equivalent of gas mileage. This superior performance is what gives the upper stage the “legs” it needs to perform high-energy missions, like delivering a satellite directly to a geostationary transfer orbit, with fuel to spare for landing.

Reason 2: Cooling. Liquid hydrogen is also the best coolant known to engineering. It has an incredibly high specific heat capacity (it can absorb a lot of energy) and is stored at an extremely low temperature (-423°F). Stoke has stated that hydrogen has five times the cooling capacity of hydrocarbon fuels like methane.

This unique combination makes liquid hydrogen the only substance in the universe that can serve as both a top-tier, high-performance rocket fuel and the industrial-strength coolant required for the regenerative heat shield. The choice was not a choice at all; it was a fundamental requirement of the physics Lapsa and Feldman had built their company upon.

The Return Trip: From Orbit to Landing

This collection of technologies comes together to create a unique and elegant operational cycle for the second stage’s return from space.

Step 1: De-Orbit. After deploying its payload, the Andromeda engine fires briefly, acting as a brake to slow the vehicle down and cause it to drop out of orbit.

Step 2: Reentry. The stage is designed to re-enter the atmosphere base-first, with its engine and heat shield facing forward. Its unique conical shape provides aerodynamic stability and gives the vehicle a “meaningful cross range.” This means it can “fly” slightly during reentry, allowing it to steer toward its precise landing target.

Step 3: Active Cooling. As it hits the upper atmosphere and temperatures skyrocket, the liquid hydrogen cooling system activates. The -423°F coolant begins circulating through the metallic heat shield, absorbing the thermal load and keeping the vehicle intact.

Step 4: Aerodynamic Braking. The vehicle’s wide, conical base acts as a highly effective drag brake. It uses the friction of the atmosphere to slow itself down from over 17,000 mph to less than 224 mph before it ever needs to restart its engine. This aerodynamic braking does most of the work for free, saving an enormous amount of propellant for landing.

Step 5: Propulsive Landing. Once it has slowed to a safe speed at a low altitude, the Andromeda engine ring re-ignites. Using its differential throttling for pinpoint steering, it performs a soft, precise, powered vertical landing back at the launch site, where it is ready to “refit, refuel, refly.”

Proving the Concept: The Hopper Test Program

A radical design like Stoke’s is useless if it only works on paper. The company’s core philosophy is to “test-as-you-fly,” building and testing hardware at a rapid pace to gather real-world data, learn from it, and iterate. This approach has been put into practice through their “Hopper” test program, a series of full-scale prototypes of the reusable upper stage.

From Hopper1 to a Successful ‘Hop’

The test program began in early 2023 with “Hopper1.” This was a full-scale ground-test article, bolted to the ground at Stoke’s test site. It was used to test the vehicle’s complex fluid mechanics and conduct “Wet Dress Rehearsals” (WDRs), where the team practices loading the vehicle with its cryogenic propellants – liquid oxygen and liquid hydrogen – and running through all the operational procedures short of ignition.

After learning from Hopper1, the team built “Hopper2,” the flight-test vehicle. On September 17, 2023, at their test site in Moses Lake, Washington, the Stoke team conducted a successful vertical takeoff and vertical landing (VTVL) test.

The flight was, by design, a “tiny little bunny hop.” The Hopper2 vehicle ignited its engine, ascended to an altitude of 30 feet, flew for 15 seconds, and then settled back down for a soft, controlled landing at its planned landing zone.

This 15-second flight was a monumental validation of Stoke’s entire, radical design. In those few seconds, Stoke successfully demonstrated, all at once:

• The novel liquid hydrogen/oxygen Andromeda engine.
• The vehicle’s ability to steer and stabilize itself using differential throttle.
• The integrated avionics, flight software, and ground control systems.

Most importantly, it proved the functionality of the actively cooled heat shield. High-resolution photos and videos from the test were unmistakable. As the Hopper2 vehicle hovered, with its hydrogen engine firing, a thick layer of ice and frost could be seen forming on the outside of the metallic heat shield. This was the “smoking gun.” It was visible, tangible proof that the -423°F liquid hydrogen was successfully circulating through the shield’s internal channels so effectively that it kept the metal cryogenically cold, even while the rocket engine was firing just feet away. It proved, in a single, elegant test, that the integrated engine and cooling system worked.

Firing Up the First Stage

In parallel with the upper stage “Hopper” tests, Stoke’s first-stage team has been developing the “Zenith” FFSC engine. This program has also moved at an incredible pace.

In June 2024, Stoke announced the first successful hotfire test of its full-flow, staged-combustion engine. This was a “major leap forward,” as it officially made Stoke only the second company in history to build and fire this advanced engine class. The team has continued to test the engine, including on a new vertical test stand, which is essential for gathering data that reflects the “test-as-you-fly” philosophy.

It’s worth noting that Stoke’s test campaign has been characterized by a string of public successes. While developmental rocket testing is notoriously difficult and explosive, and some online reports have conflated Stoke with other companies, Stoke’s public record has been one of rapid, successful, data-driven iteration. A loud “boom” heard near their test site in late 2023, for example, was later confirmed by the company to have been from a test that proceeded exactly as designed, just “louder than expected.”

A National Footprint: Design, Test, and Launch

Stoke’s rapid development speed is not an accident. It is the direct result of a “vertically integrated” and strategically co-located “infrastructure triangle,” a set of facilities designed for one purpose: maximum iteration velocity.

The Kent Headquarters: Vertical Integration

The company’s headquarters is a 168,000-square-foot facility in the Seattle suburb of Kent, Washington. This is the “design” and “build” point of the triangle. It’s not just an office building; it is a vertically integrated design and manufacturing center. Inside, Stoke’s team designs and builds its own rocket engines, vehicle structures, and avionics in-house. This vertical integration means they aren’t stuck waiting in a long supply chain for critical parts. It allows them to design a component, build it, and get it on a truck for testing, a process they say allows them to build rocket hardware in “days, not months or years.”

Moses Lake: The Need for Speed

The “test” point of the triangle is Stoke’s 75-acre private rocket test facility in Moses Lake, Washington. This is where the Hopper tests and Zenith engine firings take place. The facility has multiple test stands for engines, components, and full vehicles.

Its most important feature is its location. It is just a three-hour drive from the Kent factory. This proximity is Stoke’s secret weapon. A team can design a new injector, 3D-print it in Kent in the morning, and have it on the test stand in Moses Lake for a hotfire test that same evening. This creates an incredibly tight feedback loop. The engineers who design the hardware can be the ones running the test, seeing the data, and driving back to the factory to implement changes the next day. This ability to “test, learn, iterate, and test again” faster than any competitor is the engine of Stoke’s innovation.

Launch Complex 14: From Mercury to Nova

The “launch” point of the triangle is at Cape Canaveral Space Force Station in Florida. For its orbital missions, the U.S. Space Force has allocated Stoke a launch site.

It’s not just any pad. Stoke has been entrusted with historic Launch Complex 14 (LC-14). This pad is a National Historic Landmark, a hallowed site in American history. It is the exact launch pad from which NASA astronaut John Glenn launched on the Mercury-Atlas 6 mission in 1962, becoming the first American to orbit the Earth.

The site, which sat “quiet and dark” for over 50 years, is now being reactivated by Stoke. The company is building a modern launch facility capable of supporting the Nova rocket’s high-cadence operations, while simultaneously working to preserve the site’s historic landmarks, including the original blockhouse and monuments.

The symbolism is potent. The U.S. government is entrusting the very birthplace of America’s orbital spaceflight legacy to a startup. At LC-14, Stoke is literally building the next generation of American space access on the foundations of the first, a powerful narrative connecting the nation’s space-faring past to its commercial, reusable future.

The Market and the Money

A revolutionary idea and a rapid test program are worthless without the capital to build them and the customers to buy the final product. On this front, Stoke has executed a business strategy that is arguably as brilliant as its engineering.

A $990 Million Vote of Confidence

Stoke Space has been exceptionally successful at fundraising, securing a total of $990 million in capital. This funding, which gives the company a multi-billion-dollar valuation, has been raised in a rapid series of rounds, with each new investment validating the company’s latest technical milestones:

• Seed Round ($9.1M, Feb 2021): Led by NFX and MaC Ventures.
• Series A ($65M, Dec 2021): Led by Breakthrough Energy Ventures.
• Series B ($100M, Oct 2023): Led by Industrious Ventures, following the successful Hopper tests.
• Series C ($260M, Jan 2025):
• Series D ($510M, Oct 2025): A massive round led by Thomas Tull’s US Innovative Technology Fund (USIT).

This investor list is not typical for an aerospace company. It reveals a “dual-narrative” strategy that has unlocked a massive, diversified pool of capital.

On one side is the climate and sustainability camp, led by Breakthrough Energy Ventures, Bill Gates’ climate-tech fund. They aren’t just investing in a rocket; they are investing in a sustainable rocket. A 100% reusable vehicle that doesn’t dump millions of dollars of hardware into the ocean on every flight dramatically slashes the material waste, manufacturing footprint, and atmospheric impact of space launch. Stoke’s vision aligns perfectly with a “green” technology portfolio.

On the other side is the national security camp, led by USIT and supported by investors like In-Q-Tel (the venture capital arm of the U.S. intelligence community). Their rationale is one of strategic competition. As USIT’s Thomas Tull stated, “Launch capacity is now a defining factor in the U.S.’s ability to compete and lead in the space economy.” They see Stoke’s rapidly reusable, damage-resilient, and domestically-built rocket as a national security asset – a way to ensure “resilient, high-frequency launch operations” for the U.S. government.

By successfully framing its rocket as both a “green” solution for the climate and a “defense” solution for national security, Stoke has insulated itself from the whims of a single market and built one of the most robust capital foundations in the industry.

Validation: The U.S. Space Force

The most significant validation of Stoke’s technology and its national security narrative came in March 2025. The United States Space Force selected Stoke Space for its National Security Space Launch (NSSL) Phase 3 Lane 1 program.

This is a “kingmaker” contract. It places Stoke, a startup that has not yet reached orbit, into an elite group of only five launch companies (alongside SpaceX, ULA, Blue Origin, and Rocket Lab) deemed eligible to compete for a massive $5.6 billion pool of national security launch contracts.

This selection is not a small research grant. It is a definitive statement from the U.S. Space Force, the nation’s most demanding launch customer, that it views Stoke’s Nova rocket as a viable and necessary future vehicle for launching its most critical and sensitive national security missions. This move effectively de-risks the company’s development for all other investors and guarantees a powerful, stable anchor customer for its launch manifest.

Target Customers: A New Space Economy

With its technology validated and its funding secured, Stoke is targeting a broad spectrum of the new space economy, unlocked by the unique capabilities of its 100% reusable system.

• Satellite Constellation Deployment: This is the primary market. The Nova is perfectly sized to be a “workhorse” for deploying the next generation of satellites for global internet, Earth observation, and communications.
• National Security: The NSSL contract solidifies Stoke as a future prime launcher for defense, intelligence, and civil government payloads.
• In-Space Mobility: The reusable upper stage, with its unlimited engine restarts, isn’t just a delivery truck. It can function as a “space tug.” It can deliver a satellite to one orbit, then re-ignite its engine, travel to a different orbit to reposition or rendezvous with another asset, and then return.
• Downmass Capability: This is a market that, today, barely exists. Because the upper stage comes back, it can bring cargo from space to Earth. This “downmass” service is the key to unlocking the future of in-space manufacturing, where high-value products like perfect fiber-optics, exotic alloys, or 3D-bioprinted organs can be manufactured in the unique zero-gravity environment and then returned to Earth for sale.

The New Space Race: Stoke’s Position

Stoke Space is not operating in a vacuum. It has entered a high-stakes race with established giants, and its entire corporate strategy rests on two specific, audacious bets against its main competitors.

The 100% Reusability Challenge: Stoke vs. SpaceX

Only two companies are seriously pursuing the “holy grail” of 100% full reusability: SpaceX and Stoke. In doing so, they have made a direct, head-to-head technological wager on the best way to solve the reentry problem. This is the “Heat Shield Bet.”

SpaceX, with its Starship, is betting on passive cooling. Its upper stage is covered in thousands of modern ceramic tiles. This is a bet on manufacturing. SpaceX is betting that its world-class manufacturing-and-automation systems can produce, install, and replace these tiles so cheaply and quickly that the inherent fragility and operational inspection burden that plagued the Space Shuttle will no longer matter.

Stoke, with its Nova, is betting on active cooling. Its upper stage is protected by a single, robust, integrated metal shield that “sweats” liquid hydrogen to cool itself. This is a bet on operations. Stoke is betting that while its system is mechanically more complex, its turnaround will be operationally far simpler. Their shield is designed to be resilient to damage, shrugging off the kinds of impacts that would shatter a tile. Their wager is that this “robust and resilient” metal shield will enable an aircraft-like 24-hour turnaround that a tile-based system, which will always require detailed inspection, simply cannot match.

The Medium-Lift Market: Stoke vs. Rocket Lab

In the medium-lift market, Stoke’s most direct competitor is Rocket Lab and its upcoming Neutron rocket. Here, the companies have made a second, equally high-stakes wager. This is the “Second Stage Bet.”

Rocket Lab is taking a conservative, “Falcon 9-style” approach. Its Neutron rocket is designed to be partially reusable. The first stage will be reusable, but the upper stage is designed to be expendable and thrown away on every flight. This is a less innovative design, but it is a much simpler, faster, and cheaper engineering problem to solve. Rocket Lab is betting it can get Neutron to market quickly and capture the medium-lift customer base while Stoke is still in development.

Stoke is making the opposite bet. It is tackling the hardest problem first: the reusable second stage. This path is slower, more complex, and more capital-intensive. Stoke is betting that by the time Nova is flying, its 100% reusable system will offer a launch cost so dramatically lower that it will make Rocket Lab’s partially reusable architecture, and its need to build a new second stage for every launch, instantly obsolete.

It is a high-risk, high-reward strategy. Rocket Lab is in a race to capture the market. Stoke Space is in a race to leapfrog the entire industry.

Summary

Stoke Space entered a crowded market of over 150 rocket startups by identifying the one problem most of the industry was too intimidated to solve: the immense cost, waste, and reliability bottleneck of expendable second stages. The company was founded not by financiers, but by expert propulsion engineers from Blue Origin and SpaceX, who believed they had a unique technical solution.

That solution is a revolutionary metallic, actively-cooled heat shield. This system, which is integrated directly with the upper stage’s “Andromeda” engine, “sweats” the rocket’s own -423°F liquid hydrogen fuel to absorb the heat of reentry. It’s a design that is both the engine’s power source and the vehicle’s thermal protection. This concept was brilliantly validated in the 2023 “Hopper” test flight, when ice was seen forming on the heat shield’s exterior while the engine was firing, proving the integrated system worked.

Stoke has matched its technical audacity with a flawless business and infrastructure strategy. It has built a high-velocity “infrastructure triangle,” from its Kent manufacturing hub to its private Moses Lake test site just a three-hour drive away, enabling a development speed that competitors cannot match. It has secured the historic Launch Complex 14 at Cape Canaveral, symbolically linking the dawn of America’s space age with its reusable future.

Most tellingly, Stoke has raised nearly a billion dollars by building a unique coalition of investors. It has attracted climate-tech funds that see a sustainable “green” rocket and national-security funds that see a resilient, high-cadence defense asset. This strategy culminated in Stoke’s selection by the U.S. Space Force for the NSSL program, placing it in an elite tier of defense contractors alongside SpaceX and ULA before it has even reached orbit.

Stoke Space is not just another rocket company. It is a focused, high-stakes wager on a single, elegant piece of technology. It is betting against SpaceX’s passive tiles and Rocket Lab’s expendable second stages. If this bet on its actively cooled metallic heat shield pays off, Stoke will have solved the final and most difficult piece of the reusability puzzle, positioning itself to finally deliver the affordable, aircraft-like access to space that has been the industry’s elusive goal for decades.