Connect with us

News

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.

Published

on

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.

Advertisement

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.

Advertisement

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.

Advertisement
Comments

News

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.

Published

on

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.

Continue Reading

Elon Musk

Tesla automotive will be forgotten, but not in a bad way: investor

It’s no secret that Tesla’s automotive division has been its shining star for some time. For years, analysts and investors have focused on the next big project or vehicle release, quarterly delivery frames, and progress in self-driving cars. These have been the big categories of focus, but that will all change soon.

Published

on

(Credit: Tesla)

Entrepreneur and Angel investor Jason Calacanis believes that Tesla will one day be only a shade of how it is recognized now, as its automotive side will essentially be forgotten, but not in a bad way.

It’s no secret that Tesla’s automotive division has been its shining star for some time. For years, analysts and investors have focused on the next big project or vehicle release, quarterly delivery frames, and progress in self-driving cars. These have been the big categories of focus, but that will all change soon.

I subscribed to Tesla Full Self-Driving after four free months: here’s why

Eventually, and even now, the focus has been on real-world AI and Robotics, both through the Full Self-Driving and autonomy projects that Tesla has been working on, as well as the Optimus program, which is what Calacanis believes will be the big disruptor of the company’s automotive division.

On the All-In podcast, Calcanis revealed he had visited Tesla’s Optimus lab earlier this month, where he was able to review the Optimus Gen 3 prototype and watch teams of engineers chip away at developing what CEO Elon Musk has said will be the big product that will drive the company even further into the next few decades.

Calacanis said:

“Nobody will remember that Tesla ever made a car. They will only remember the Optimus.”

He added that Musk “is going to make a billion of those.”

Musk has stated this point himself, too. He at one point said that he predicted that “Optimus will be the biggest product of all-time by far. Nothing will even be close. I think it’ll be 10 times bigger than the next biggest product ever made.”

He has also indicated that he believes 80 percent of Tesla’s value will be Optimus.

Optimus aims to totally revolutionize the way people live, and Musk has said that working will be optional due to its presence. Tesla’s hopes for Optimus truly show a crystal clear image of the future and what could be possible with humanoid robots and AI.

Continue Reading

News

Tesla Robotaxi fleet reaches new milestone that should expel common complaint

There have been many complaints in the eight months that the Robotaxi program has been active about ride availability, with many stating that they have been confronted with excessive wait times for a ride, as the fleet was very small at the beginning of its operation.

Published

on

Credit: Tesla

Tesla Robotaxi is active in both the Bay Area of California and Austin, Texas, and the fleet has reached a new milestone that should expel a common complaint: lack of availability.

It has now been confirmed by Robotaxi Tracker that the fleet of Tesla’s ride-sharing vehicles has reached 200, with 158 of those being available in the Bay Area and 42 more in Austin. Despite the program first launching in Texas, the company has more vehicles available in California.

The California area of operation is much larger than it is in Texas, and the vehicle fleet is larger because Tesla operates it differently; Safety Monitors sit in the driver’s seat in California while FSD navigates. In Texas, Safety Monitors sit in the passenger’s seat, but will switch seats when routing takes them on the highway.

Tesla has also started testing rides without any Safety Monitors internally.

Tesla Robotaxi goes driverless as Musk confirms Safety Monitor removal testing

This new milestone confronts a common complaint of Robotaxi riders in Austin and the Bay, which is vehicle availability.

There have been many complaints in the eight months that the Robotaxi program has been active about ride availability, with many stating that they have been confronted with excessive wait times for a ride, as the fleet was very small at the beginning of its operation.

With that being said, there have been some who have said wait times have improved significantly, especially in the Bay, where the fleet is much larger.

Tesla’s approach to the Robotaxi fleet has been to prioritize safety while also gathering its footing as a ride-hailing platform.

Of course, there have been and still will be growing pains, but overall, things have gone smoothly, as there have been no major incidents that would derail the company’s ability to continue developing an effective mode of transportation for people in various cities in the U.S.

Tesla plans to expand Robotaxi to more cities this year, including Miami, Las Vegas, and Houston, among several others.

Continue Reading