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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.

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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.

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.

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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.

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’s xAI Secures $3B Investment From Saudi AI Firm HUMAIN

The transaction converts HUMAIN’s xAI stake into SpaceX shares, positioning the Saudi-backed firm as a significant minority shareholder in the newly combined entity.

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Credit: xAI

Saudi artificial intelligence firm HUMAIN has confirmed a $3 billion Series E investment in xAI just weeks before the startup’s merger with SpaceX.

The transaction converts HUMAIN’s xAI stake into SpaceX shares, positioning the Saudi-backed firm as a significant minority shareholder in the newly combined entity.

The investment gives HUMAIN exposure to what has been described as one of the largest technology mergers on record, combining xAI’s artificial intelligence capabilities with SpaceX’s scale, infrastructure, and engineering base, as noted in a press release.

“This investment reflects HUMAIN’s conviction in transformational AI and our ability to deploy meaningful capital behind exceptional opportunities where long-term vision, technical excellence, and execution converge, xAI’s trajectory, further strengthened by its acquisition by SpaceX, one of the largest technology mergers on record, represents the kind of high-impact platform we seek to support with significant capital” HUMAIN CEO Tareq Amin stated.

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The investment also positions HUMAIN for potential long-term equity upside should SpaceX proceed with a public offering.

The investment expands on an existing partnership announced in November 2025 at the U.S.-Saudi Investment Forum. Under that agreement, HUMAIN and xAI committed to jointly develop more than 500 megawatts of next-generation AI data center and compute infrastructure in Saudi Arabia.

The collaboration also includes deployment of xAI’s Grok models within the kingdom, aligning with Saudi Arabia’s broader strategy to build domestic AI capacity and attract global technology players.

HUMAIN, backed by the Public Investment Fund, is positioning itself as a full-stack AI player spanning advanced data centers, cloud infrastructure, AI models, and applied solutions. The Series E investment deepens its role from development partner to major shareholder in the Musk-led AI and space platform.

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Tesla Giga Berlin plant manager faces defamation probe after IG Metall union complaint

Prosecutors in Frankfurt (Oder) confirmed they have opened a defamation probe into Gigafactory Berlin plant manager André Thierig.

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Credit: @Gf4Tesla/X

Tesla’s Giga Berlin plant manager is now under investigation after a complaint from trade union IG Metall, escalating tensions ahead of next month’s works council elections. 

Prosecutors in Frankfurt (Oder) confirmed they have opened a defamation probe into Gigafactory Berlin plant manager André Thierig, as per a report from rbb24.

A spokesperson for the Frankfurt (Oder) public prosecutor’s office confirmed to the German Press Agency that an investigation for defamation has been initiated following a criminal complaint filed by IG Metall against Thierig.

The dispute stems from Tesla’s allegation that an IG Metall representative secretly recorded a works council meeting using a laptop. In a post on X, Thierig described the incident as “truly beyond words,” stating that police were called and a criminal complaint was filed.

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“What has happened today at Giga Berlin is truly beyond words! An external union representative from IG Metall attended a works council meeting. For unknown reasons, he recorded the internal meeting and was caught in action! We obviously called police and filed a criminal complaint!” Thierig wrote in a post on X.

Police later confirmed that officers did seize a computer belonging to an IG Metall member at Giga Berlin. Prosecutors are separately investigating the union representative on suspicion of breach of confidentiality and violation of Germany’s Works Constitution Act.

IG Metall has denied Tesla’s allegations. The union claimed that its member offered to unlock the laptop for review in order to accelerate the investigation and counter what it called false accusations. The union has also sought a labor court injunction to “prohibit Thierig from further disseminating false claims.”

The clash comes as Tesla employees prepare to vote in works council elections scheduled for March 2–4, 2026. Approximately 11,000 Giga Berlin workers are eligible to participate in the elections.

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Tesla wins FCC approval for wireless Cybercab charging system

The decision grants Tesla a waiver that allows the Cybercab’s wireless charging system to be installed on fixed outdoor equipment.

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Credit: Tesla AI/X

Tesla has received approval from the Federal Communications Commission (FCC) to use Ultra-Wideband (UWB) radio technology in its wireless EV charging system. 

The decision grants Tesla a waiver that allows the Cybercab’s wireless charging system to be installed on fixed outdoor equipment. This effectively clears a regulatory hurdle for the company’s planned wireless charging pad for the autonomous two-seater.

Tesla’s wireless charging system is described as follows in the document: “The Tesla positioning system is an impulse UWB radio system that enables peer-to-peer communications between a UWB transceiver installed on an electric vehicle (EV) and a second UWB transceiver installed on a ground-level pad, which could be located outdoors, to achieve optimal positioning for the EV to charge wirelessly.”

The company explained that Bluetooth is first used to locate the charging pad. “Prior to the UWB operation, the vehicular system uses Bluetooth technology for the vehicle to discover the location of the ground pad and engage in data exchange activities (which is not subject to the waiver).”

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Once the vehicle approaches the pad, the UWB system briefly activates. “When the vehicle approaches the ground pad, the UWB transceivers will operate to track the position of the vehicle to determine when the optimal position has been achieved over the pad before enabling wireless power charging.”

Tesla also emphasized that “the UWB signals occur only briefly when the vehicle approaches the ground pad; and mostly at ground level between the vehicle and the pad,” and that the signals are “significantly attenuated by the body of the vehicle positioned over the pad.”

As noted by Tesla watcher Sawyer Merritt, the FCC ultimately granted Tesla’s proposal since the Cybercab’s wireless charging system’s signal is very low power, it only turns on briefly while parking, it works only at very short range, and it won’t interfere with other systems.

While the approval clears the way for Tesla’s wireless charging plans, the Cybercab does not appear to depend solely on the new system.

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Cybercab prototypes have frequently been spotted charging at standard Tesla Superchargers across the United States. This suggests the vehicle can easily operate within Tesla’s existing charging network even as the wireless system is developed and deployed. With this in mind, it would not be surprising if the first batches of the Cybercab that are deployed and delivered to consumers end up being charged by regular Superchargers.

DA-26-168A1 by Simon Alvarez

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