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Stoke Space to build SpaceX Raptor engine’s first real competitor
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.
The update that's rolling out to the fleet makes full use of the front and rear steering travel to minimize turning circle. In this case a reduction of 1.6 feet just over the air— Wes (@wmorrill3) April 16, 2024
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.
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.
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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.
Elon Musk
The Boring Company’s newest tunnel vehicle runs on Tesla parts and no one is driving it
The Boring Company’s new tunnel vehicle runs on Tesla Model 3 batteries and drive units.
The Boring Company just introduced a new piece of hardware, and it runs on parts pulled straight from a Tesla showroom. Liner Truck 3, unveiled in a post from the tunneling company’s official X account, is an all electric vehicle built around Tesla Model 3 battery packs and drive units, purpose built to move concrete tunnel segments to the boring machine face without a single person underground.
Introducing Liner Truck 3 — our latest fully electric tunnel vehicle.
– Tesla Model 3 battery and drive units
– Transports 22,000+ lb of concrete segments to the boring machine
– 28 miles of range
– 12 mph max operating speed
– Remotely piloted from Global OCC in Texas, with… pic.twitter.com/XB7FgSXnpy— The Boring Company (@boringcompany) August 7, 2026
The job itself is unglamorous but critical. Each precast segment run weighs more than 22,000 pounds, roughly the load of a full cement mixer, and Liner Truck 3 hauls that weight repeatedly between the surface staging area and wherever the Prufrock machine happens to be cutting.
The Boring Company said Liner Truck 3 is piloted remotely out of its Global Operations Control Center in Texas, extending the Zero-People-In-Tunnel approach the company has spent years building toward. An earlier version of a ZPIT liner truck was already tested at the company’s Bastrop, Texas research tunnels, and a factory tour released last month showed an employee flying a fully loaded liner truck with a PlayStation controller. Liner Truck 3 looks like the production version of that same idea, cleaned up and pushed into daily use.
The timing lines up with a company digging in more places than it ever has before. The Boring Company now has multiple Prufrock machines active or arriving in Nashville, where Music City Loop construction has been accelerating since February, and its Vegas Loop network keeps adding tunnel mileage on a near monthly basis. Every one of those projects depends on getting concrete segments to the cutting face fast enough to keep the boring machine from idling, which is exactly the bottleneck Liner Truck 3 is designed to remove.
It also reinforces something Tesla owners have watched happen gradually across Musk’s companies: passenger car hardware finding a second life in heavy equipment. Model 3 drive units already move people through the Vegas Loop, and now the same components are hauling concrete underground in Nashville and wherever The Boring Company digs next. Whether that kind of component reuse extends further into TBC’s equipment lineup, or into other Musk owned industrial hardware, is the next thing worth watching.
SpaceX stock did the opposite of what most of Wall Street expected this week, when the day designed to be its most dangerous turned into a rally, and the rally kept going.
Thursday marked the first major lockup expiration since SpaceX’s June IPO, making roughly 911.5 million insider held shares eligible to trade for the first time, more than doubling the company’s public float. Analysts and short sellers had spent weeks bracing for a flood of selling, especially after the stock fell 13 percent following its first earnings report as a public company on Tuesday. Instead, shares rose 6.1 percent Thursday to close at $114.92, and by Friday they were trading near $129, up more than another 12 percent on the day.
SpaceX shorts get warned by Musk ally, echoing Tesla’s early struggles
The setup made the outcome notable. Short interest had climbed to roughly 34 percent of the float heading into earnings, among the highest of any large cap stock, with about 95 percent of available shares to borrow already on loan. CEO Elon Musk warned short sellers twice in the weeks before the lockup, writing on X that “the survival probability of firms who maintain a significant short position in SpaceX over time is very low,” then following up on the morning of earnings with “I try to warn them, but they just double down.”
When the newly unlocked shares hit the market and the selloff never showed up, some of that short position appears to have started unwinding. TipRanks reported that options activity shifted toward bullish strategies like put selling and risk reversals following the rally, with roughly $600 million in options premium trading Thursday alone. Retail buyers also stepped in during the earnings dip, according to Vanda Research.
The fundamentals behind the stock have not changed much in a week. SpaceX’s revenue nearly doubled year over year to $7.8 billion, with Starlink subscribers doubling to 12 million and the company’s AI segment growing 247 percent. What spooked investors on Tuesday was the spending side. Capital expenditures jumped to more than $18 billion for the quarter, up from $2.8 billion a year earlier, with AI investment alone rising from $749 million to $15.8 billion. Wall Street remains split on whether that spending is building infrastructure SpaceX needs or outrunning what the business can currently support, a debate Teslarati has tracked since shares first came under pressure.
None of that resolves the bigger question hanging over the stock. Thursday’s release was only the first of nine staggered lockup tranches, with roughly $800 billion worth of additional shares scheduled to become eligible through October, and Musk’s own stake stays locked until next June. If this week is any indication, the market is treating that supply as something it can absorb rather than something to fear, at least for now.
News
The Boring Company’s newest Vegas Station has a permit quietly waiting behind it
Sahara Las Vegas opened a new Vegas Loop station, joining an exclusive two resort transit club.
Sahara Las Vegas opened a new Vegas Loop station Thursday, giving The Boring Company’s underground transit system its northernmost stop yet on the Strip. The station sits at Sahara’s Paradise Road entrance, on the southeast corner of Las Vegas Boulevard and Sahara Avenue, and connects riders to the Las Vegas Convention Center, other Strip resorts on the network and, eventually, Harry Reid International Airport.
The addition makes Sahara the second resort, after Fontainebleau opened its own station in January, to get a stop built at street level rather than tucked into the property itself. Sahara now joins Westgate as the only two Strip resorts offering both a Vegas Loop station and a stop on the Las Vegas Monorail, giving guests two separate ways to get around without leaving the property.
The Boring Company just doubled its tunneling power in Nashville
The bigger news buried in Thursday’s announcement is what comes next. Boring Company has already secured its first permit to tunnel north of Sahara Avenue, extending the network beyond where it currently ends, even though permits to push the Loop toward downtown Las Vegas still haven’t been granted. Crews are also working on a two mile dual tunnel line running from Westgate to a planned station at 4744 Paradise Road, just north of Tropicana Avenue, that Las Vegas Convention and Visitors Authority CEO Steve Hill has said the company hopes to open in time for November’s Las Vegas Grand Prix.
Ridership has grown alongside the buildout. The Loop moved roughly 82,000 passengers during CONEXPO in early March, a total the company highlighted on its own X account at the time, and the system has now carried more than 4 million passengers through 11 open stations since it began running in 2021. The airport connector tunnels, meant to give the Loop a direct link to Harry Reid, have slipped past their original first quarter target and remain under construction, with Boring Company director Mike Baier saying that a full opening is still a few months out.
For Sahara, the calculation is straightforward. Convention traffic drives a large share of Loop ridership, and a station at the property’s front door gives conventiongoers one more reason to book rooms on the Strip’s north end instead of closer to the convention center itself.
The Boring Company’s newest tunnel vehicle runs on Tesla parts and no one is driving it
Elon Musk and SpaceX shrugs off the trading day Wall Street feared most
