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SpaceX begins stress-testing upgraded Super Heavy booster
In a what is likely a prelude to engine installation, SpaceX has begun stress-testing an upgraded Super Heavy booster prototype.
Known as Super Heavy Booster 7 or B7, the prototype is the first of its kind designed to support up to 33 new Raptor V2 engines – each potentially capable of producing up to 230 tons (~510,000 lbf) of thrust at liftoff. Even with just 20 such engines installed, Super Heavy – measuring around 69 meters (~225 ft) tall and nine meters (~30 ft) wide – will be the largest and most powerful rocket stage ever tested. That potentially unprecedented power is why SpaceX has custom-built a complex structural test stand to explore Super Heavy’s true performance envelope in a slightly less risky manner.
In the second half of 2021, that structural test stand briefly tested an unusual half-Starship, half-Super Heavy test tank with a nine-engine thrust section (‘puck’) and later compressed a different test tank until its reinforced steel skin buckled. In the interim, SpaceX removed its nine-ram setup and modified the stand to support 13 rams, guaranteeing that its new purpose was to test Super Heavy’s new 13-engine thrust section. Prior to Booster 7, all Super Heavy prototypes have had a similar nine-engine puck and an outer ring of 20 engines that would attach directly to the rim of each booster’s cylindrical body.
Increasing the central engine count from 9 to 13 was already certain to up the amount of stress future Super Heavy thrust pucks would need to survive by almost 45%. But combined with Raptor V2’s thrust increases, Super Heavy Booster 7’s thrust puck could actually be subjected to at least 80% more thrust at liftoff. Altogether, Super Heavy B7’s 33 engines should be able to produce ~7600 tons (~16.8M lbf) of thrust compared to Super Heavy B4’s ~5400 tons (~11.9M lbf). As a result, though it’s odd that SpaceX never did significantly test Booster 4, it’s no surprise that the company chose to give Booster 7 priority as soon it was ready.
After a few false starts and at least one ‘pneumatic proof test’ that likely saw Booster 7 pressurized with benign nitrogen gas, SpaceX began stress-testing the upgraded Super Heavy in earnest on April 14th. First, the booster was filled about a third of the way with roughly 1000 tons (~2.2M lb) of liquid nitrogen (LN2) or a combination of liquid oxygen (LOx) and LN2. Once the rocket was fully chilled, there were clear signs of some kind of added stress as large sheets of ice that had formed on the side of B7’s skin broke apart and fell off.
Only ice close to Super Heavy’s base was visibly disturbed, increasing the odds that the behavior was a sign of some or all of the structural test stand’s hydraulic rams simulating Raptor engines. It’s also possible that the stress was caused by pressurizing Super Heavy’s tanks to the point that they began to appreciably deform, though that type of testing is far harder to differentiate. Without official comments, it’s unfortunately impossible to ever know what exactly SpaceX is testing or how successful those tests are when the structural test stand is involved.
Nonetheless, it’s likely that Booster 7 isn’t done with the stand just yet. SpaceX could benefit from just about any data gathered about the performance of Super Heavy’s new thrust puck during simulated Raptor startup, throttling, and shutdown both at liftoff and during boostback and landing burns. SpaceX might also want to simulate engine-out scenarios that would result in asymmetric thrust.
Assuming Booster 7 survives this particular series of tests and SpaceX is happy with its performance on the structural test stand, the upgraded Super Heavy could be ready for Raptor installation and integrated wet dress rehearsal and static fire testing in the near future. SpaceX began delivering upgraded Raptors V2 engines to Starbase in late March.
Elon Musk
Tesla Cybercabs narrowly miss deadly Amazon cargo plane crash
An Amazon cargo plane crash near Miami’s airport stopped feet from dozens of Tesla Cybercabs.
An Amazon Prime Air Boeing 767 cargo jet overran the runway at Miami International Airport on Sunday afternoon, killing five people and injuring five more. The jet, operated by North Carolina based carrier 21 Air as Flight 7598, touched down around 2 p.m. after arriving from San Juan, Puerto Rico, then crossed the airport perimeter, plowed across NW 67th Avenue and struck multiple vehicles before catching fire, according to the Associated Press.
Photos and video from the scene show the aircraft’s nose stopped within meters of a fenced staging lot holding dozens of gold painted Tesla Cybercabs, the steering wheel free robotaxi Tesla began putting on public roads in Austin last week. Miami-Dade Fire Rescue has confirmed the plane struck “multiple vehicles” but has not said whether any Cybercabs were among them, and neither Tesla nor airport officials have addressed the fleet directly.
The Cybercabs had not yet entered commercial service in Miami. Tesla’s existing Robotaxi operation there runs on modified Model Y vehicles and has been unsupervised since Ashok Elluswamy confirmed the detail on X in July.
Footage of the plane crash from earlier today | #ONLYinDADE pic.twitter.com/iGoOtnd6cD
— ONLY in DADE (@ONLYinDADE) September 6, 2026
Elon Musk offered the briefest of reactions. Replying to a Zero Hedge post about the Cybercabs sitting so close to the wreckage, he wrote a single word: “Weird.” He has not commented further, and Tesla has not issued a statement.
The timing puts Tesla’s newest vehicle near an unrelated but highly visible tragedy just days after its Austin debut, a launch that had already drawn scrutiny from federal regulators. The National Highway Traffic Safety Administration opened an audit how Tesla certified the Cybercab as compliant with federal vehicle safety standards, a process Teslarati covered after the vehicle’s September 3 launch event. That inquiry concerns the car’s lack of a steering wheel and pedals, not the Miami crash.
Investigators from the FAA and NTSB are focused on the plane, not the parking lot beside it. Flight data reviewed by outlets including Simple Flying show the 767 touched down around 170 knots, well above the 135 to 140 knot range typical for the aircraft, though investigators have not determined a cause. Amazon said it is working with authorities and that its priority is the safety of everyone affected.
Whether any Cybercabs were damaged, and what Tesla plans for the fleet parked near one of the country’s busiest airports, remain open questions.
Tesla has reached a notable benchmark in its autonomous driving program after its Robotaxi fleet surpassed one million miles of unsupervised operation. The company made the announcement during its Cybercab event in Austin on September 3.
Tesla Vice President of AI Ashok Elluswamy told attendees he was happy to report the fleet had achieved one million miles of unsupervised Robotaxi operation as a testament to safety.
The new total marked a sharp increase from the 380,000 unsupervised miles Tesla disclosed during its second-quarter 2026 earnings update in late July.
In roughly six weeks, the company added about 620,000 miles. That acceleration followed Tesla’s decision to remove in-vehicle safety monitors from most of its operations outside the San Francisco Bay Area.
Credit: Tesla
Tesla first launched Robotaxi service in Austin in June 2025 with safety drivers present. It later began fully unsupervised rides and expanded into Dallas, Houston, Miami, Orlando, and Tampa. The San Francisco Bay Area remains the exception, where a safety monitor still rides in the vehicle under California permitting rules.
The company has not released a city-by-city breakdown of the one million unsupervised miles.
The milestone arrived as Tesla began offering public Cybercab rides in Austin. The purpose-built vehicle has no steering wheel or pedals and is designed only for autonomous ride-hailing. Production versions joined the existing fleet of modified Tesla vehicles already operating in the service.
Tesla’s unsupervised mileage is growing at a double-digit weekly rate according to earlier company comments, yet its fleet size remains modest compared with established competitors. Waymo has accumulated more than 200 million fully autonomous rider-only miles. Tesla has described its own unsupervised operations as having recorded zero notable incidents in the period leading up to the July update.
The one-million-mile figure reflects Tesla’s shift from supervised testing to broader driverless service in multiple states. It also highlights the company’s strategy of using both existing Model Y vehicles and the new Cybercab to scale its network.
Credit: Tesla
Whether the rapid recent growth continues will depend on further city expansions, regulatory approvals, and the performance of the purpose-built Cybercab in everyday paid rides. Tesla has not specified how many of the latest miles involved the new vehicle versus the rest of the fleet.
The announcement underscores Tesla’s progress toward a larger robotaxi network while illustrating the remaining gap in total autonomous experience relative to longer-operating rivals.
Tesla AI lead Ashok Elluswamy said this week that 24-hour Robotaxi service is close. Replying on X to a rider who wanted Cybercab trips all night, he wrote that the capability would arrive “next month or so” once “the next tech to merge on the v15 plan” is ready.
The comment landed on September 4, one day after Tesla opened public Cybercab rides in Austin. It is the clearest near-term timeline yet for overnight unsupervised operation. Tesla’s paid Robotaxi network currently runs from 6 a.m. to 10 p.m. seven days a week across Austin, Dallas, Houston, Miami, Orlando, and Tampa.
next month or so. the next tech to merge on the v15 plan will enable it.
— Ashok Elluswamy (@aelluswamy) September 4, 2026
That 16-hour window is shorter than the 6 a.m. to 2 a.m. schedule the company used for much of the prior year.
Elluswamy did not name the specific feature or say whether the change would apply first to purpose-built Cybercabs, the existing Model Y fleet, or both. He also offered no city-by-city rollout list. The link to Full Self-Driving v15 is nevertheless significant.
Tesla has described v15 as a step-change architecture with seven parallel improvement tracks and roughly ten times more parameters than earlier builds. Early versions of that software already operate on the Robotaxi fleet and contain about 40 percent of the planned gains.
By July 2026, the unsupervised fleet had logged more than 380,000 miles across six cities in two states with what the company called an impeccable safety record and no notable incidents caused by the vehicles themselves. Tesla has repeatedly argued that camera-based end-to-end neural networks, rather than extra sensors, are the core of the solution.
Overnight service would test that claim in lower-light conditions and would also raise vehicle utilization, a key variable for Robotaxi unit economics. The company has already begun using public Superchargers at night and is building dedicated Robotaxi charging sites.
Riders have asked why software must change if the cars already drive in the dark. The practical answer appears to be reliability and scale: Tesla has held back mass expansion until more of the v15 stack is merged, citing the need for higher confidence before putting thousands of unoccupied vehicles on streets around the clock.
If the next module arrives on the timetable Elluswamy sketched, 24-hour service could begin in October 2026 in at least some markets.
That would mark a shift from a daytime-bounded pilot to a service that can run whenever demand exists, including the late-night hours that have so far remained out of reach.
Tesla Cybercabs narrowly miss deadly Amazon cargo plane crash
Tesla crosses major Unsupervised Self-Driving milestone
