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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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Tesla CEO Elon Musk outlines expectations for Cybercab production

“…initial production is always very slow and follows an S-curve. The speed of production ramp is inversely proportionate to how many new parts and steps there are. For Cybercab and Optimus, almost everything is new, so the early production rate will be agonizingly slow, but eventually end up being insanely fast.”

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Credit: Tesla

Tesla CEO Elon Musk outlined expectations for Cybercab production as the vehicle is officially set to start rolling off manufacturing lines at the company’s Giga Texas factory in less than 100 days.

Cybercab is specifically designed and catered to Tesla’s self-driving platform and Robotaxi ride-hailing service. The company has been pushing hard to meet its self-set expectations for rolling out an effective self-driving suite, and with the Cybercab coming in under 100 days, it now needs to push for Unsupervised Self-Driving in the same time frame.

Tesla CEO Elon Musk confirms Robotaxi is set to go unsupervised

This is especially pertinent because the Cybercab is expected to be built without a steering wheel or pedals, and although some executives have said they would build the car with those things if it were necessary.

However, Musk has maintained that the Cybercab will not have either of those things: it will have two seats and a screen, and that’s it.

With production scheduled for less than 100 days, Musk broke down what people should expect from the initial manufacturing phases, being cautiously optimistic about what the early stages will likely entail:

“…initial production is always very slow and follows an S-curve. The speed of production ramp is inversely proportionate to how many new parts and steps there are. For Cybercab and Optimus, almost everything is new, so the early production rate will be agonizingly slow, but eventually end up being insanely fast.”

Musk knows better than most about the challenges of ramping up production of vehicles. With the Model 3, Musk routinely refers to it as “production hell.” The Cybertruck, because of its polarizing design and stainless steel exterior, also presented challenges to Tesla.

The Cybercab definitely presents an easier production process for Tesla, and the company plans to build millions of units per year.

Musk said back in October 2024:

“We’re aiming for at least 2 million units a year of Cybercab. That will be in more than one factory, but I think it’s at least 2 million units a year, maybe 4 million ultimately.”

When April comes, we will find out exactly how things will move forward with Cybercab production.

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Tesla reveals awesome Model 3 and Model Y incentive, but it’s ending soon

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Credit: Tesla Europe & Middle East/X

Tesla has revealed an awesome Model 3 and Model Y incentive to help consumers make the jump to one of its affordable mass-market vehicles, but it’s ending soon.

Tesla is offering one free upgrade on eligible inventory of the Model 3 and Model Y until February 2.

This would help buyers receive the most expensive paid option on the vehicle at no additional cost, meaning white interior or a more premium paint option will be free of charge if you take delivery on or before February 2.

Tesla states on its website for the offer:

“Only for limited inventory while supplies last. Price displayed on inventory listings already deducts the cost of the free option.”

This latest incentive is just another advantage Tesla has by selling its vehicles directly and not using some sort of dealership model that relies on approvals from higher-ups. It is important to note that these programs are offered to help stimulate demand and push vehicles into customers’ hands.

It is not the only incentive Tesla is currently offering, either. In fact, there is a much larger incentive program that Tesla is working on, and it has to do with Full Self-Driving transfers, which could result in even more sales for the company through Q1.

Tesla is ending its FSD Transfer program on March 31, as it plans to transition to a Subscription-only basis with the self-driving suite for anyone who has not already purchased it outright.

This could help drive some on-the-fence buyers to new vehicles, but it remains to be seen. Given the timing of the program’s demise, it appears Tesla is hoping to use it to add additional sales and bolster a strong Q1 2026.

Interior and exterior paint colors can add up to $2,000 if you choose the most premium Ultra Red body color, or an additional $1,000 for the Black and White interior option. The discount, while small, could help get someone their preferred design configuration, instead of settling for something that is not quite what they want.

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Tesla Full Self-Driving gets outrageous insurance offer with insanely cheap rates

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Credit: Ashok Elluswamy/X

Tesla Full Self-Driving is getting an outrageous insurance offer with insanely cheap rates that will slash the cost of coverage by 50 percent.

Lemonade, a digital insurance company, has launched its first-of-a-kind product known as Lemonade Autonomous Car Insurance, and it is starting with an exclusive offer to FSD. The new offer will cut rates for FSD-engaged driving by “approximately 50 percent,” highlighting the data that shows a significantly safer driving environment when the suite is activated and engaged.

The company also said it plans to introduce even cheaper rates as Tesla continues to release more advanced FSD versions through software updates. Tesla has been releasing new FSD versions every few weeks, highlighting vast improvements for those who have the latest AI4 chip.

The announcement comes just a few months afterLemonade Co-Founder and President Shai Wininger said that he wanted to insure FSD vehicles for “almost free.” He said that Tesla’s API complemented Lemonade’s AI-based platform because it provides “richer and more accurate driving behavior data than traditional UBI devices.”

Tesla Full Self-Driving gets an offer to be insured for ‘almost free’

In mid-December, Lemonade then offered Tesla owners in California, Oregon, and Arizona the opportunity to connect their vehicles directly to the company’s app, which would provide a direct connection and would require a separate telematics device, which is required with other insurance providers who offer rates based on driving behaviors.

This latest development between Lemonade and Tesla is something that Wininger believes will be different because of the advanced nature of FSD:

“Traditional insurers treat a Tesla like any other car, and AI like any other driver. But a car that sees 360 degrees, never gets drowsy, and reacts in milliseconds can’t be compared to a human.”

He went on to say that the existing pay-per-mile product has given the company something that no traditional insurer has been able to offer. This comes through Lemonade’s “unique tech stack designed to collect massive amounts of real driving data for precise, dynamic pricing.”

The reputation FSD has gathered over the past few years is really impressive. Wininger backed this with some more compliments:

“Teslas driven with FSD are involved in far fewer accidents. By connecting to the Tesla onboard computer, our models are able to ingest incredibly nuanced sensor data that lets us price our insurance with higher precision than ever before.”

The product will begin its official rollout in Arizona on January 26. Oregon will get it a month later.

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