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Stoke Space to build SpaceX Raptor engine’s first real competitor

Stoke Space has begun testing parts of an engine similar to SpaceX's famous Raptor.

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Seattle startup Stoke Space has revealed plans to develop an efficient rocket engine similar to the Raptors that power SpaceX’s Starship.

Formed in October 2019, Stoke Space secured its first significant round of funding – $9.1 million – less than three years ago. At that time, CEO and co-founder Andy Lapsa says that the startup had just five employees, no permanent workspace, and a “barren field” for a test site. Within 18 months, Stoke Space had turned that empty field into an impressive test facility, conducted numerous component tests, and assembled its first full-scale rocket engine – an exotic UFO-like device unlike any seen before.

It also raised another $65 million – enough funding to begin earnestly developing a potentially revolutionary rocket capable of launching more than 1.65 tons (~3600 lb) into orbit for less than half a million dollars. To realize that extremely ambitious goal, Stoke Space has taken the even more ambitious step of attempting to make the first rocket it develops fully reusable. Simultaneously, the company has incorporated several exotic technologies into that rocket, recently culminating in a surprise announcement that it will attempt to develop one of the most difficult types of engines to power that rocket’s booster stage.

Full-flow staged combustion

At the end of an extended interview and tour with YouTuber Tim Dodd (The Everyday Astronaut), CEO Andy Lapsa revealed that Stoke Space has decided to build a full-flow staged combustion (FFSC) engine for the first stage of its reusable rocket. FFSC is the most efficient type of combustion cycle available for a chemical bipropellant rocket engine, but it’s also the most difficult to develop.

A full-flow engine attempts to squeeze every possible ounce of performance out of the propellant it consumes. The most powerful and efficient chemical rocket engines must consume huge volumes of propellant in a short amount of time without destroying the launch vehicle they’re attached to. To create pressure and spin the pumps that are needed to feed that propellant into their main combustion chamber, engines often burn a small amount of propellant in a separate gas generator or preburner. Gas-generator engines vent that exhaust overboard, reducing efficiency but making for a much simpler design. Staged-combustion engines use preburners to create gas that pumps liquid propellant, and that exhaust gas is eventually injected into the main combustion chamber.

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Full-flow staged combustion sets itself apart by having two separate pumps and preburners for oxidizer and fuel. Unlike simpler variants of staged combustion, FFSC engines turn all of their propellant into gas before injecting it into the combustion chamber. That hot gas increases the heat of combustion and the pressure inside the combustion chamber, ensuring that virtually all of the propellant that flows through the engine is combusted and turned into thrust as efficiently as possible. FFSC is exceptionally difficult because of the extra-high temperatures and pressures it requires, as well as the need for an oxygen-rich preburner and pump. In a high-pressure, hot-oxygen environment, virtually anything imaginable – including most metals – will spontaneously combust.

Only complex custom-designed alloys can survive those conditions. SpaceX’s Raptor, the only FFSC engine that has ever flown, is especially difficult because it’s meant to be highly reusable. To be successful, Raptor will have to survive those conditions dozens or even hundreds of times in a row with little to no maintenance in between.

The first booster engine Stoke Space ever attempts to build will be a reusable full-flow staged combustion engine powered by liquid methane and liquid oxygen – essentially a smaller version of SpaceX’s Raptor. Stoke’s booster is otherwise familiar and features deployable landing legs like SpaceX’s Falcon boosters. Lapsa says it will likely also have grid fins.

Reusing the upper stage

In some ways, the upper stage of Stoke’s first rocket is even more ambitious. Powered by hydrogen and oxygen propellant, Stoke has designed a conical capsule-like upper stage with an integral fairing. The upper stage’s propulsion is exotic and unique. A large pump will feed propellant to up to 30 combustion chambers distributed around the rim of its heat shield. The exhaust coming from those 30 chambers will expand and partially push against the upper stage’s equally exotic metallic, liquid-cooled heat shield. That expansion against the heat shield improves the efficiency of the upper stage and means that its engine will technically be an aerospike.

Stoke has already begun testing a full-scale version of the upper stage’s UFO-like rocket engine with 15 combustion chambers. Since testing began in the second half of 2022, Stoke has completed dozens of static fires. Everyday Astronaut’s tour also revealed that the startup has made significant progress fabricating and assembling its first full-scale upper stage prototype – tanks, nosecone, heat shield, engine, and all.

Reminiscent of SpaceX’s Grasshopper and Starhopper campaigns, Stoke plans to conduct hop tests with that prototype if it makes it through qualification testing. On February 7th, Stoke also revealed that it’s begun testing a crucial component of its full-flow booster engine. All told, Stoke Space is making progress at a remarkable pace and continues to tackle the hardest problems. The startup has also avoided widely publicizing any specific deadlines, instead choosing to let hardware and tangible results speak for themselves. Only time will tell if that approach pays off, but Stoke is off to an exceptionally impressive start in an industry full of impressive rocket startups.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Elon Musk

Elon Musk takes aim at Bill Gates’ Microsoft with new AI venture “Macrohard”

It is quite an appropriate name for a company that’s designed to rival Microsoft.

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Credit: xAI/X

Elon Musk has set his sights on Microsoft with a new company called “Macrohard,” a software venture tied to his AI startup, xAI. 

Musk described the project as a “purely AI software company” that’s designed to generate hundreds of specialized coding and generative AI agents that could one day simulate products from companies like Microsoft entirely through artificial intelligence.

Macrohard‘s Purpose

Musk announced Macrohard on Friday, though xAI had already registered the trademark with the US Patent Office a few weeks ago, as noted in a PC Mag report. Interestingly enough, this is not the first time that Musk has mentioned such an initiative.

Just last month, he stated that xAI was “creating a multi-agent AI software company, where Grok spawns hundreds of specialized coding and image/video generation/understanding agents all working together and then emulates humans interacting with the software in virtual machines until the result is excellent.”

At the time, Musk stated that “This is a macro challenge and a hard problem with stiff competition,” hinting at the venture’s “Macrohard” moniker. A few years ago, Musk also posted “Macrohard >> Microsoft” on X. 

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Powered by xAI and Colossus

Macrohard appears to be closely linked to xAI’s Colossus 2 supercomputer project in Memphis. Musk has confirmed plans to acquire millions of Nvidia GPUs, joining rivals such as OpenAI and Meta in a high-stakes race for AI computing power. Colossus is already one of the most powerful supercomputer clusters in the world, and it is still being expanded.

xAI is only a couple of years old, having been founded in March 2023. During its Engineering Open House event in San Francisco, Elon Musk highlighted that the company’s speed will be its primary competitive edge. “No SR-71 Blackbird was ever shot down and it only had one strategy: to accelerate,” Musk said.

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Elon Musk

Elon Musk confirms he’s still in wartime CEO mode

He is still locked in.

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Wcamp9, CC BY 4.0 , via Wikimedia Commons

Elon Musk tends to use social media platform X as his personal platform to express himself, so much so that critics tend to allege that the CEO is no longer serious about his numerous companies. 

As per Musk, he is still very much in wartime CEO mode, despite all the jokes and fun posts about Ani on X. 

Elon Musk leads several prolific companies, much more than the average CEO. And while Tesla is the only publicly traded entity that he currently leads, Musk is so visible that everyone across the internet pretty much has a strong opinion of him one way or another. For his longtime supporters and followers, however, what truly matters is if Musk is locked in.

Considering that Elon Musk’s feed on X has recently been filled with AI imagery, a good portion of which involve AI-rendered women, some X users have expressed concerns that the CEO may be losing focus once more. Musk responded to one such user by highlighting his very busy schedule and his numerous active projects. 

Needless to say, Elon Musk is still locked in. He is still in “wartime CEO” mode.

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As per the CEO, even his recent AI posts about AI are “part of a broader vision and strategy.” He also highlighted that SpaceX’s Starship Flight 10 is launching in a few days, xAI’s Grok 5 is starting its training next month, and Tesla’s Autopilot V14 is also coming next month. As per Musk, “long-term strategy is compelling.”

Elon Musk’s comments are quite accurate. While he may seem to spend all his time on X, after all, he is very much still neck-deep in all his companies’ projects. There is a reason why Musk became known as a visionary, and a lot of it is because he really is intimately involved in all of his companies’ projects. 

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Tesla watchers spot mysterious castings at Fremont Factory

The castings seem to be quite new, as they do not seem to match any of the castings that are currently being used for the Model Y.

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Credit: @metgodinwilderness7130/YouTube

A recent flyover of the Fremont Factory has triggered speculations about Tesla’s ongoing initiatives that are yet to be unveiled publicly. This was hinted at by the sighting of some apparent vehicle castings around the factory that have never really been observed before.

A Fremont Factory flyover

In a recent update, drone operator Met God in Wilderness, who has been chronicling the progress and developments of the Fremont Factory for years, shared some footage from his August 14, 2025 flyover. Based on the video, the Fremont Factory seemed very much alive. Vehicles were being pumped out of the factory, and a rather interestingly covered car could be seen going around the test track.

What is quite fascinating about the footage from the Fremont Factory is the fact that the vehicles that were moving from the production line to the outbound logistics lot are not driven manually anymore. As per Tesla in previous updates, vehicles produced at the Fremont Factory navigate to the outbound logistics lot on their own using Unsupervised FSD

Mysterious castings

Perhaps most interestingly, the drone operator also managed to capture some footage of some castings that were being gathered just outside one of the facility’s sprung structures. These castings seem to be quite new, as they do not seem to match any of the castings that are currently being used for the Model Y. This has brought speculations suggesting that the new components, which seem smaller than standard Model Y megacasts, may be for a different, perhaps more compact, vehicle. 

As per Tesla in its second quarter earnings call, the company actually started the initial production of more affordable models sometime in June. These vehicles, as per Elon Musk, will be made available for consumers in the fourth quarter. “Given that we started in North America and that our goal is to maximize production with higher rates by the end of Q3, we’re going to keep pushing hard on our current models to avoid complexity… We’ll be running with the more affordable models available for everyone in Q4,” Musk said.

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Watch the recent drone footage of the Fremont Factory in the video below.

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