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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 will perform Starship double catch attempt with Flight 15

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Credit: SpaceX

SpaceX plans to attempt what will be a defining moment in rocket reusability on Starship Flight 15.

As Elon Musk announced in a recent X post, SpaceX will attempt to catch both the Super Heavy Booster and the Starship upper stage during the upcoming orbital flight. If successful, it will mark the first time that all parts of an orbital rocket return to Earth intact, a breakthrough Musk has called essential to making life multiplanetary.

Previous flights have demonstrated the tower-catch technique with Super Heavy. SpaceX has successfully caught V1 boosters three times (on Flights 5, 7, and 8), with some even reflown. The Ship upper stage has never been caught.

Returning from orbital velocity after deploying payload makes it a significantly harder challenge due to higher energy, heat loads, and the need for precise belly-flop reentry, a flip maneuver, and a final landing burn to settle between the Mechazilla tower’s chopstick arms.

Flight 15, using Booster 22 and Ship 42 (both Block 3 vehicles), is targeted for no earlier than Friday, November 13, 2026, from Orbital Launch Pad 2 at Starbase, Texas. The 75-minute window opens at 4:45 p.m. CT, pending regulatory approval. After hot staging and separation, the booster is planned to return for a catch roughly 6 minutes and 35 seconds after liftoff.

The Ship will insert into a roughly 275 km orbit, deploy 26 advanced Starlink V3 satellites, complete about 14 orbits over more than 22 hours, and—if systems check out—perform a deorbit burn, reentry, flip, and landing burn for a tower catch at approximately T+22 hours 32 minutes.

SpaceX confirms Starship 15 launch window with massive ambitions

A simulation shown during SpaceX’s October earnings call depicted the Ship descending in a belly-flop attitude, flipping upright with a short engine burn, and being captured by the arms:

Contingency splashdown zones exist in the Gulf of Mexico (booster) and Pacific (Ship) if a catch is not viable. SpaceX has stressed rigorous health checks before committing the Ship to a return-to-launch-site trajectory.

Musk has described the odds of success on this first dual-catch attempt as “more likely than not,” noting a steady stream of additional flights is already scheduled if needed. Full recovery would enable rapid inspection, refurbishment, and reflight—slashing costs and supporting the high launch cadence required for Starlink expansion, lunar missions, and eventual Mars settlement.

As Musk put it, this is “the critical breakthrough needed to make life multiplanetary.”

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Tesla Cybercab is set to get some massive improvements

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Credit: TechOperator | X

Tesla Cybercab is going to get some pretty substantial updates, including improvements to efficiency and a new color.

CEO Elon Musk said in a post on X on Saturday that Tesla would be working to refine the Cybercab even more, following the announcement during the week that the company would eliminate the Cybertruck lines within Giga Texas for more Cybercab manufacturing capacity.

“There are efficiency improvements coming that will allow for a 40kWh Cybercab pack,” Musk posted on X. “We will make this in liquid silver, so the colors are not too monotonous.”

A new, more efficient model of the Cybercab will be engineered, which will only help Tesla’s profitability and margins, and it also boosts the argument for why the Cybertruck should be discontinued, at least from a business perspective.

The current Cybercab that operates in the Robotaxi platform in Austin, Texas, has a 48 kWh pack, and it sounds like Musk believes Tesla is on its way to introducing a version that has fewer cells but can manage the same workload thanks to engineering efficiencies.

Credit: Tesla

Musk also doubled down on the decision to prioritize Cybercab production over Cybertruck, which is a decision that has been extremely polarizing within the community, and many fans have made it abundantly clear that they are not particularly pleased with the plans.

“If we have to maintain a complex production line, supply chain, and allocate engineering for Cybertruck, we can’t use those people or factory space and machinery for scaling Cybercab, which is the vehicle that will PROFOUNDLY transform the world of terrestrial transport,” Musk said.

Cybercab is obviously Tesla’s path forward in an automotive sense. It seems that Tesla is less concerned about catering to the passenger vehicle market and is more prone to focus on transforming passenger transportation in a way that prioritizes autonomy. However, this requires some sacrifice on Tesla’s end, and the Cybertruck is unfortunately a victim of this.

Cybercab holds an extremely crucial part of Tesla’s future. With the company already revolutionizing passenger transportation once, this is the next phase, and Cybercab is the path forward.

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Tesla Robotaxi app update now tells riders if Cybercab is the better choice

Tesla’s Robotaxi app now shows ETAs, wait times and availability for Cybercab and Model Y.

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Concept art of a Tesla Cybercab in Las Vegas Strip as rendered via Grok

Tesla has rolled out a new vehicle selection screen in its Robotaxi app, and it puts the numbers riders care about most in front of them before they book.

Version 26.11.0 of the app shows the estimated arrival time, the expected wait and current availability for each vehicle option on a single screen, according to a video shared by @gheeunit  on X on November 7. Riders deciding between a Cybercab and a Model Y Robotaxi can now compare those figures side by side instead of picking a car first and learning how long it will take afterward.

Tesla first gave riders that choice on September 3, the day paid Cybercab rides began in Austin. The original version of the screen listed the Cybercab, which seats two, next to the Model Y, which seats four. A later build, 26.8.2, added a seating capacity indicator so groups knew which car would fit them. What it did not show was whether choosing the Cybercab meant standing on the curb a few extra minutes.

That question matters more now than it did two months ago. Tesla had 45 Cybercabs on the Texas DMV roster when rides started. By late October the state listed 573, alongside 631 Model Ys, and community trackers logged a record 1,576 Cybercab sightings across Austin on Halloween alone. With two large fleets sharing one service area, the closest car and the quickest pickup are not always the same vehicle.

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Inline availability also changes what happens when demand spikes. If no Cybercab is free nearby, the rider sees that on the selection screen rather than after trying to book one.

For now the comparison is mostly an Austin feature. Riders in Dallas, Houston, Fort Worth and the Florida markets are still matched with Model Y vehicles, though Tesla said on its third quarter earnings call that Cybercab rides would launch in Dallas this month.

The update follows a steady run of smaller changes to the rider experience. Late last month Tesla brought a quiet mode that blacks out the cabin screen to Model Y Robotaxis after first testing it in the Cybercab, and it has stretched Austin service to run from 6 a.m. to 2 a.m.

The Cybercab side of that selection screen is about to get much busier. Elon Musk said this week that Tesla will wind down Cybertruck production at Gigafactory Texas around the middle of 2027 to make room for more Cybercab output, and Tesla has said it is aiming to get Cybercabs to customers by the end of this year.

Tesla has not published official release notes for version 26.11.0.

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