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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 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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Tesla CEO Elon Musk trolls budget airline after it refuses Starlink on its planes

“I really want to put a Ryan in charge of Ryan Air. It is your destiny,” Musk said.

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elon musk ryanair

Tesla CEO Elon Musk trolled budget airline Ryanair on his social media platform X this week following the company’s refusal to adopt Starlink internet on its planes.

Earlier this week, it was reported that Ryanair did not plan to install Starlink internet services on its planes due to its budgetary nature and short flight spans, which are commonly only an hour or so in total duration.

Initially, Musk said installing Starlink on the company’s planes would not impact cost or aerodynamics, but Ryanair responded on its X account, which is comical in nature, by stating that a propaganda it would not fall for was “Wi-Fi on planes.”

Musk responded by asking, “How much would it cost to buy you?” Then followed up with the idea of buying the company and replacing the CEO with someone named Ryan:

Polymarket now states that there is an 8 percent chance that Musk will purchase Ryanair, which would cost Musk roughly $36 billion, based on recent financial data of the public company.

Although the banter has certainly crossed a line, it does not seem as if there is any true reason to believe Musk would purchase the airline. More than anything, it seems like an exercise of who will go further.

Starlink passes 9 million active customers just weeks after hitting 8 million

However, it is worth noting that if something is important enough, Musk will get involved. He bought Twitter a few years ago and then turned it into X, but that issue was much larger than simple banter with a company that does not want to utilize one of the CEO’s products.

In a poll posted yesterday by Musk, asking whether he should buy Ryanair and “restore Ryan as their rightful ruler.” 76.5 percent of respondents said he should, but others believe that the whole idea is just playful dialogue for now.

But it is not ideal to count Musk out, especially if things continue to move in the direction they have been.

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Tesla Robotaxi’s biggest rival sends latest statement with big expansion

The new expanded geofence now covers a broader region of Austin and its metropolitan areas, extended south to Manchaca and north beyond US-183.

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Credit: @AdanGuajardo/X

Tesla Robotaxi’s biggest rival sent its latest statement earlier this month by making a big expansion to its geofence, pushing the limits up by over 50 percent and nearing Tesla’s size.

Waymo announced earlier this month that it was expanding its geofence in Austin by slightly over 50 percent, now servicing an area of 140 square miles, over the previous 90 square miles that it has been operating in since July 2025.

Tesla CEO Elon Musk shades Waymo: ‘Never really had a chance’

The new expanded geofence now covers a broader region of Austin and its metropolitan areas, extended south to Manchaca and north beyond US-183.

These rides are fully driverless, which sets them apart from Tesla slightly. Tesla operates its Robotaxi program in Austin with a Safety Monitor in the passenger’s seat on local roads and in the driver’s seat for highway routes.

It has also tested fully driverless Robotaxi services internally in recent weeks, hoping to remove Safety Monitors in the near future, after hoping to do so by the end of 2025.

Although Waymo’s geofence has expanded considerably, it still falls short of Tesla’s by roughly 31 square miles, as the company’s expansion back in late 2025 put it up to roughly 171 square miles.

There are several differences between the two operations apart from the size of the geofence and the fact that Waymo is able to operate autonomously.

Waymo emphasizes mature, fully autonomous operations in a denser but smaller area, while Tesla focuses on more extensive coverage and fleet scaling potential, especially with the potential release of Cybercab and a recently reached milestone of 200 Robotaxis in its fleet across Austin and the Bay Area.

However, the two companies are striving to achieve the same goal, which is expanding the availability of driverless ride-sharing options across the United States, starting with large cities like Austin and the San Francisco Bay Area. Waymo also operates in other cities, like Las Vegas, Los Angeles, Orlando, Phoenix, and Atlanta, among others.

Tesla is working to expand to more cities as well, and is hoping to launch in Miami, Houston, Phoenix, Las Vegas, and Dallas.

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