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SpaceX delays Starhopper’s first flight a few days despite Raptor preburner test success
SpaceX has (partially) ignited Starhopper’s freshly-installed Raptor engine, successfully verifying that the engine is ready for its next major test: a full ignition and static firing. Although successful, SpaceX still has some work to do before the vehicle is ready for its first untethered flight(s).
July 15th’s progress is just the latest in a several day-series of preflight tests designed to reduce the likelihood that Starhopper is destroyed over the coming days and (hopefully) weeks. If all goes planned during the awkward Starship prototype’s first foray into hover tests, SpaceX CEO Elon Musk has stated that he will provide an official presentation updating the public on the status of the company’s ever-changing next-generation rocket.
The past week or so of Starhopper preflight testing began with Raptor serial number 6 (SN06) completing the last of a series of acceptance test fires in McGregor, Texas on June 10th. Even on its own, this was a major milestone for the new SpaceX engine: Raptor SN06 was the first of the new, full-scale engines to pass the acceptance test program with flying colors. According to Musk, for the engine to complete those tests so successfully, SpaceX had to solve a challenging bug in which some sort of mechanical resonance (i.e. vibration) damaged or destroyed Raptors SN01-05.
Hours later, the engine began a short ~450 mi (720 km) journey south to Starhopper, located in Boca Chica, Texas. The engine arrived on July 11th and was fully installed on Starhopper by the following evening (July 12th), at which point SpaceX put Starhopper and Raptor through some mild but valuable thrust vector controller (TVC) tests, wiggling the car-sized engine to ensure it can accurately steer the prototype rocket.
Around two days after the above ‘wiggle’ test was successfully completed, SpaceX moved into the next stage, partially fueling Starhopper with liquid methane and oxygen propellant and helium pressurant in what is known in rocketry as a wet dress rehearsal (WDR). The (implicitly) successful WDR was capped off with a duo of what can now safely be concluded were some sort of Raptor test preceding even pre-ignition operations. Whatever the tests were, they appear to have been completed successfully.
That appears to be the case because less than 24 hours after their completion, on July 15th, SpaceX once again began loading Starhopper with propellant and pressurant for a second round of wet testing. This time around, SpaceX got right into more critical Raptor tests once enough propellant was loaded, igniting the engine’s interwoven oxygen and methane preburners.
Previously discussed 24 hours ago in a Teslarati article focused on Raptor wiggles and other miscellaneous tests, Raptor is an extremely advanced rocket engine based on a cycle (i.e. how propellant is turned into thrust) known as full-flow staged combustion.
“In a staged-combustion engine like Raptor, getting from the supercool liquid oxygen and methane propellant to 200+ tons of thrust is quite literally staged, meaning that the ignition doesn’t happen all at once. Rather, the preburners – essentially their own, unique combustion chambers – ignite an oxygen- or methane-rich mixture, the burning of which produces the gas and pressure that powers the turbines that bring fuel into the main combustion chamber. That fuel then ignites, producing thrust as they exit the engine’s bell-shaped nozzle.
Unintuitively, conditions inside the preburner – hidden away from view – are actually far more intense than the iconic blue, purple, and pink flame that visibly exists Raptor’s nozzle. Much like hot water will cool while traveling through pipes, the superheated gaseous propellant that Raptor ignites to produce thrust will also cool (and thus lose pressure) as it travels from Raptor’s preburner to its main combustion chamber. If the pressure produced in the preburners is too low, Raptor’s thrust will be (roughly speaking) proportionally limited at best. At worst, low pressure in the preburners can trigger a “hard start” or shutdown that could destroy the engine. According to Elon Musk, Raptor’s oxygen preburner thus has the worst of it, operating at pressures as high or higher than 800 bar (11,600 psi, 80 megapascals).”
In full-flow staged combustion (FFSC), even more complexity is added as all propellant that touches the engine must necessarily end up traveling through the main combustion chamber to eke every last ounce of thrust out of the finite propellant a rocket lifts off with. As such, FFSC engines can be about as efficient as the laws of physics allow any given chemical rocket engine to be, at the cost of exceptional complexity and brutally difficult development.
Additionally, FFSC physically requires two separate preburners and then makes things even harder by making each separate preburner (methane and oxygen) depend on each other’s operation for the engine to fully ignite. This means that no individual preburner can be used to kickstart Raptor – instead, SpaceX must somehow spin the turbopumps that feed propellant into each preburner with some separate system. This is all just to emphasize the fact that Raptor’s ignition sequence is a spectacularly complex orchestra of valves, spark plugs, sensors, and magic. This is why it’s valuable for Raptor to test its preburner system independently of an actual ignition test, at least as long as the engine is still in the development stages.
According to NASASpaceflight.com managing editor Chris Bergin, what this practically translates to is a minor Starhopper hover test delay of 1-2 days, while the static fire has also been pushed roughly 24 hours from July 15th to July 16th. If that full static fire produces lots of happy data, Starhopper could be cleared for a hover test debut attempt as early as Wednesday or Thursday (July 17/18).
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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
