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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.

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.

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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.

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

SpaceX just cleared a key FCC hurdle in its fight with Verizon and AT&T

The FCC accepted SpaceX’s bid for Grain’s 800 MHz spectrum, opening review for Starlink Mobile.

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A hand holds a smartphone displaying the Starlink Mobile app interface showing a strong “Connected – Direct to Cell” signal, with a Starlink satellite beaming connectivity signals down to Earth from orbit. The background features the planet’s night side glowing with city lights against the curve of the atmosphere, set above a scenic twilight landscape.

The Federal Communications Commission has formally opened its review of SpaceX’s plan to buy a nationwide block of 800 MHz spectrum from Grain Management, moving Starlink Mobile one step closer to operating as a full U.S. wireless carrier.

In a public notice issued Tuesday, the FCC’s Wireless Telecommunications Bureau said it accepted for filing the applications to transfer control of two Grain license companies, Prism License Co. 1 and Prism License Co. 2, to Starlink Spectrum Holdings, a wholly owned SpaceX subsidiary. The deal covers 546 paired licenses across 3,224 counties, reaching roughly 100% of the U.S. population in all 50 states, Washington, D.C., Puerto Rico and the U.S. Virgin Islands. The proceeding sits under WT Docket No. 26-313.

Acceptance is not approval. It means the applications cleared an initial review and the public comment window is now open. Comments and petitions to deny are due December 1, and oppositions are due December 8. The bureau also said the conditions attached to Grain’s July purchase of the licenses from T-Mobile, which require rapid buildout for terrestrial and direct to device service, would carry over to SpaceX if the transfer is approved.

SpaceX announced the agreement on October 8, saying the new airwaves would let Starlink Mobile’s signal reach phones inside buildings, something its 2 GHz spectrum from EchoStar cannot do as well. The portfolio includes up to 14 MHz of paired spectrum in the 817 to 824 MHz and 862 to 869 MHz bands, which most existing phones already support. Elon Musk called it “the last critical piece of the spectrum puzzle needed for SpaceX to provide complete phone coverage in America.”

According to the filing, SpaceX would hold up to 89 MHz of total spectrum in any given market after the deal closes, including up to 14 MHz below 1 GHz. That is far under the 385 MHz threshold the FCC uses to flag a transaction for closer competitive scrutiny, and well short of the roughly 300 MHz each of AT&T, Verizon and T-Mobile holds.

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Tuesday’s notice does not decide how SpaceX can use the spectrum from orbit. A separate application SpaceX filed on October 27 seeking authority to provide supplemental coverage from space on the same frequencies, along with related waiver requests, is still pending before the commission.

The ground network is already taking shape. Last week, SpaceX picked Qualcomm to supply radios, baseband units and software for a nationwide 5G build, with deployment across tens of thousands of U.S. cell sites starting in 2027. The FCC also voted on October 29 to advance a proposal opening another 482 MHz to direct to device service, though AT&T, Verizon and T-Mobile hacritive pushed to strip nearly 300 MHz from it. SpaceX President Gwynne Shotwell has said service on SpaceX’s own airwaves is targeted for early 2028.

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Cybertruck

Tesla upfitter offers to keep Cybertruck alive

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Credit: Unplugged Performance

A Tesla upfitter has offered to take over Cybertruck lines from the company in a last-ditch effort to save the all-electric pickup from being completely canceled in the middle of 2027.

Unplugged Performance, the Hawthorne, California-based Tesla aftermarket specialist, has publicly offered to take over Cybertruck production from Tesla, funding the effort “through a consortium of investors.”

The proposal comes as Tesla prioritizes its Cybercab Robotaxi program and prepares to wind down Cybertruck assembly at Gigafactory Texas around mid-2027.

Founded in 2013 by Ben Schaffer and located adjacent to Tesla’s Design Studio and SpaceX, Unplugged Performance has become a leading provider of premium upgrades for Tesla vehicles, including extensive Cybertruck packages under its UP INVINCIBLE line.

Through its UP.FIT division, the company has also developed purpose-built police and fleet versions of the Cybertruck, including deliveries to agencies such as the Las Vegas Metropolitan Police Department.

In an X post on Tuesday, Unplugged said:

“An open offer to Tesla: We fully support putting Cybercab first, and we’d be glad to take the Cybertruck line off your hands. We’d fund it with a consortium of investors and run it at no cost to Tesla’s floor space, headcount, or focus. All of that goes to Cybercab. Cybercab gets first call on battery cells too. We’ll wait our turn. Tesla gains incremental profit: a license fee, plus FSD and Robotaxi network revenues on every vehicle built. We’d build the Cybertruck, a three-row CyberSUV, and an unmanned CyberCargo hauler. More autonomous miles, across every surface of this planet and beyond. Worth a conversation?”

The arrangement would free Tesla resources and manufacturing capacity for Cybercab while allowing continued production of the stainless-steel pickup and expanded variants. Unplugged Performance indicated it would wait for battery cells after Cybercab needs are met and would generate ongoing revenue for Tesla through licensing and software/network services on the vehicles it produces.

Following strong initial interest, Unplugged Performance posted a follow-up inviting potential investors and strategic partners to email cyber@unpluggedperformance.com. The company clarified that the outreach is solely to gauge interest and does not constitute an offer to sell securities or acceptance of funds at this stage.

The proposal arrives shortly after Elon Musk indicated that Cybertruck production in Texas would be phased out by roughly the middle of 2027 to expand Cybercab output.

Whether Tesla engages with the offer remains to be seen, but the public overture highlights both the aftermarket specialist’s deep experience with the Cybertruck platform and the growing focus on autonomy within Tesla’s manufacturing plans.

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Elon Musk

Elon Musk says Tesla Cybercab future is ‘obvious to anyone with eyes and a brain’

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Elon Musk said the Tesla Cybercab will perform “a majority of all passenger miles” where it is allowed to operate and that point is “obvious to anyone with eyes and a brain.”

Musk used the point to double down on the company’s decision to ax the cult-favorite Cybertruck, as its production space will be removed and transitioned into additional Cybercab lines. The move has catalyzed a polarizing conversation on whether its right or wrong.

Whatever side you are on — it’s happening.

Regardless, Musk seems to be getting to the point that he is done talking about the choice. At some point, you have to think that this was truly a difficult decision for him and the company as well, and this is not something he took lightly. In fact, he’s probably a little bit disappointed with it, too.

But the point remains that the Cybertruck is gone. Musk’s focus is purely on developing an autonomous platform that the world will utilize for transportation, and he’s telling you that anyone “with eyes and a brain” can see it:

Tesla is betting that all of its passengers in the future will be okay with not owning their own personal cars and will be fine with ride-hailing for the rest of their lives. Every dinner, every errand, every trip to the airport and transportation thereafter, will all be operated by ride-sharing, and in Tesla’s perfect world, it will happen in a Cybercab.

As of now, Cybercab is only active in Austin, but it has been spotted all over the country with a driver behind the wheel in those prototypes. In Austin, the car has no steering wheel or pedals for people to control the vehicle.

The Cybertruck dilemma is one that has truly come across the entire Tesla community and while it seems to be a great idea to keep it because people love it, the business side of things is steering Musk and Tesla in another direction.

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