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SpaceX’s Starship explosion explained by Elon Musk

The burning wreckage of Starship SN4, May 29th. (SPadre)

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Shortly after a briefing following SpaceX’s flawless astronaut launch debut, CEO Elon Musk casually revealed the best explanation yet for why a Starship prototype violently exploded during testing on May 29th.

On that fated Saturday, SpaceX successfully completed the fifth static fire of a Raptor engine installed on a full-scale Starship prototype, preceded by about an hour and a half of vehicle checks and propellant loading. Unfortunately, around a minute after Raptor shut down, what was quickly identified as liquid methane began spurting out of a specific section at the base of Starship, rapidly creating a massive cloud as the cryogenic propellant boiled and turned into gas. The specific source is unclear but moments later, something under Starship SN4 provided the shock or spark needed to ignite the expanding fire hazard, producing a spectacularly large and violent explosion.

Unsurprisingly, the accidental fuel-air explosion that was created obliterated Starship SN4 in the blink of an eye, shredding its lower (liquid oxygen) tank into steel confetti and immediately breaching the upper (liquid methane) tank, which fell to the ground and subsequently exploded again. The launch mount Starship was staged on was also damaged beyond repair and has been fully dismantled and scrapped in the two days since the anomaly. Thankfully, however, SpaceX already has replacement mounts and ships well on their way to carrying Starship SN4’s torch forward and Elon Musk already seems to understand what caused the prototype’s demise.

Shortly after a post-launch briefing celebrating and discussing SpaceX’s inaugural astronaut launch on May 30th, Reuters reporter Joey Roulette was able to ask Musk about Starship SN4’s spectacular demise the day prior. The SpaceX CEO was quoted saying that “what we thought was going to be a minor test of a quick disconnect ended up being a big problem”, confirming suspicions based on careful analysis of public views of the explosion that it was caused by issues with Starship’s ground support equipment (GSE).

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Starhopper’s quick-disconnect umbilical panel is pictured here in May 2019. Starship SN4 used a similar mechanism, although the plumbing is now located inside the vehicle’s circumference. (NASASpaceflight – bocachicagal)

In Musk’s statement, “quick disconnect” (QD) refers to an umbilical port that connects a launch vehicle to GSE, enabling the loading and offloading of propellant and fluids, clamping down the rocket, and providing a wired telemetry and communications link for ground controllers. QDs must perform all those tasks while also being able to rapidly release and disconnect, allowing the rocket to lift off while still protecting its sensitive ports for ease of reuse.

In theory, Starship’s quick-disconnect umbilical panel is even more complex, as it will have to simultaneously enable the ship to be fueled and controlled while sitting on top of a Super Heavy booster and permit in-orbit docking and refueling. Given that Starships are currently being tested independently on spartan launch mounts, it’s unclear if the current generation of prototypes has been outfitted with advanced QD panels. More likely, Musk was referring to a test of a less advanced QD panel similar to the rough version used on Starhopper last year, and SpaceX simply wanted to test its ability to disconnect and reconnect to Starship on command.

SpaceX’s existing Starship launch mount was heavily damaged by SN4’s explosion and has since been fully dismantled. (NASASpaceflight – bocachicagal)
Starship SN4’s remains have already been cleared from the pad. (NASASpaceflight – bocachicagal)

If that’s the case, the likeliest explanation for SN4’s explosion is that that quick disconnect was unable to fully reconnect after the test, resulting in a leak from the liquid methane port when SpaceX began to detank the rocket. Instead of the highly-pressurized fluid flowing smoothly back to ground storage tanks, the liquid methane sprayed wildly, akin to the effect one might observe when attempting to block off an active water source with an open palm.

Work on a second launch mount was already ongoing when Starship SN4 exploded on May 29th. (NASASpaceflight – bocachicagal)
Starship SN5 and SN6 are simultaneously being assembled in SpaceX’s new vertical assembly building (VAB). (NASASpaceflight – bocachicagal)

Compared to the many possible ways a fueled Starship could fail, a propellant leak started by a faulty umbilical panel is about as convenient as they come. Starship SN4 may have been violently destroyed as a result, turning a relatively small error into exceptionally painful lesson but SpaceX has already had some success building full-scale prototypes at an almost unbelievably low cost – likely less than $10M apiece. Starship SN5 appears to be just shy of ready to take SN4’s place on the launch mount, although SpaceX will have to build an entirely new launch mount before it can resume testing.

At the same time, Starship SN5’s successor – SN6 – is just one stacking event away from reaching a level of completion similar to SN4 and SN5. All told, Starship SN4’s demise is just another part of the process of developing a new kind of rocket by building and testing hardware – failure can be a valuable tool when managed properly. Based on past observations, SpaceX could be ready to continue testing (and hopefully flying) Starship prototypes before the end of the month.

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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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California hits Tesla Cybercab and Robotaxi driverless cars with new law

California just gave police power to ticket driverless cars, including Tesla’s Cybercab fleet.

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Concept rendering of Tesla Cybercab being cited by CA Highway Patrol (Credit: Grok)

California DMV formally adopted new rules on April 29, 2026 that allow law enforcement to issue “notices of noncompliance”, or in other words ticket autonomous vehicle companies when their cars commit moving violations. The rules take effect July 1, 2026 and officially closes a regulatory gap that previously let driverless cars operate on public roads with nearly no traffic enforcement consequences.

Until now, state traffic laws only applied to human “drivers,” which meant that when no person was behind the wheel, police had no mechanism to issue a ticket. Officers were limited to citing driverless vehicles for parking violations only. A well-known example came in September 2025, when a San Bruno officer watched a Waymo robotaxi execute an illegal U-turn and could do nothing but notify the company.

Under the new framework, when an officer observes a violation, the autonomous vehicle company is effectively treated as the driver. Companies must report each incident to the DMV within 72 hours, or 24 hours if a collision is involved. Repeated violations can result in fleet size restrictions, operational suspensions, or full permit revocation. Local officials also gained new authority to geofence driverless vehicles out of active emergency zones within two minutes and require a live emergency response line answered within 30 seconds.

Tesla Cybercab ramps Robotaxi public street testing as vehicle enters mass production queue

California’s new enforcement rules arrive at a pivotal moment for Tesla. The company is ramping Cybercab production at Giga Texas toward hundreds of units per week, targeting at least 2 million units annually at full capacity, while simultaneously pushing to expand its Robotaxi service to dozens of U.S. cities by end of 2026. Unsupervised FSD for consumer vehicles is currently targeted for Q4 2026, and when it arrives, Tesla’s fleet may not have a human to absorb legal accountability, under the July 1 rules.

Tesla has confirmed plans to expand its Robotaxi service to seven new cities in the first half of 2026, including Dallas, Houston, Phoenix, Miami, Orlando, Tampa, and Las Vegas, with the service already running without safety drivers in Austin. Musk has said he expects robotaxis to cover between a quarter and half of the United States by end of year.

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Tesla Model X shocks everyone by crushing every other used car in America

The Model X is one of Tesla’s flagship models, the other being the Model S. Earlier this year, Tesla confirmed it would discontinue production of both the Model S and Model X to make way for Optimus robot production at the Fremont Factory in Northern California.

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Credit: Tesla Asia | X

The Tesla Model X was the fastest-selling used vehicle in the United States in the first quarter of the year, crushing every other used car in America.

iSeeCars data for the first quarter shows that the Model X was the fastest-selling used car, lasting just 25.6 days on the market on average, two days better than that of the second-place Lexus RX 350h. The Cybertruck, Model Y, and Model S, in seventh, ninth, and thirteenth place, respectively, also made the list.

The Model X is one of Tesla’s flagship models, the other being the Model S. Earlier this year, Tesla confirmed it would discontinue production of both the Model S and Model X to make way for Optimus robot production at the Fremont Factory in Northern California.

Tesla brings closure to flagship ‘sentimental’ models, Musk confirms

Bringing closure to these two vehicles signaled the end of the road for the cars that have effectively built Tesla’s reputation for luxury and high-end passenger vehicles.

Relying on the sales of its mass market Model Y and Model 3, as well as leaning on the success of future products like the Cybercab, is the angle Tesla has chosen to take.

Teslas are also performing extremely well as a whole on the resale market. iSeeCars data shows that, “while the average price of a 1- to 5-year-old non-Tesla EV fell 10.3% in Q1 2026 year-over-year, the average price of a used Tesla was essentially flat at 0.1% lower across the same period. Traditional gas car prices dropped 2.8% during this same period.”

Additionally, market share for gas cars has dropped nearly 3 percent since the same quarter last year. Tesla has remained level, while the non-Tesla EV market share has increased 30 percent, mostly due to more models available.

Nevertheless, those non-Tesla EVs have seen their value drop by over 10 percent, while Tesla’s values have remained level.

Executive Analyst Karl Brauer said:

“Used electric vehicles without a Tesla badge have lost more than 10% of their value in the past year. This compares to stable values for Teslas and hybrids, and a modest 2.8% drop for traditional gasoline vehicles.”

Teslas, as well as non-luxury hybrids, are displaying the strongest resistance in the face of faltering demand, the publication says. But the more impressive performance is that of the Model X alone.

Tesla’s decision to stop production of the Model X may have played some part in the vehicle’s pristine performance in Q1. With the car already placed at a premium price point, used models are already more appealing to consumers. Perhaps second-hand versions were more than enough for those who wanted a Model X, and only a Model X.

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Cybertruck

Tesla Cybertruck’s head-scratching trim sold terribly, recall documents reveal

The head-scratching offering was only available for a few months, and evidently, it did not sell very well, which we all suspected. New recall documents on the vehicle from the National Highway Traffic Safety Administration (NHTSA) now reveal just how poorly it sold.

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Credit: Tesla

After Tesla decided to build a Rear-Wheel-Drive Cybertruck trim back in 2025, which was void of many features and only featured a small discount.

The head-scratching offering was only available for a few months, and evidently, it did not sell very well, which we all suspected. New recall documents on the vehicle from the National Highway Traffic Safety Administration (NHTSA) now reveal just how poorly it sold.

The recall deals with a potentially separating wheel stud and potentially impacts 173 Cybertruck units with the 18-inch steel wheels. The Cybertruck RWD was the only trim level to feature these, and the 173 potentially impacted units represent a portion of the population of pickups. Therefore, it’s not the entire number of RWD Cybertruck sold, but it could show how little interest it gathered.

The NHTSA document states:

“On affected vehicles, higher severity road perturbations and cornering may strain the stud hole in the wheel rotor, causing cracks to form. If cracking propagates with continued use and strain, the wheel stud could eventually separate from the wheel hub.”

Only 5 percent are expected to be impacted, meaning less than 10 units will have the issue if the NHTSA and Tesla estimates are correct. Nevertheless, the true story here is how terribly the RWD Cybertruck sold.

Tesla ended production and stopped offering the RWD Cybertruck to customers last September. For just $10,000 less than the All-Wheel-Drive trim, Tesla offered the RWD Cybertruck with just one motor, textile seats instead of leather, only 7 speakers instead of 15, no Rear Touchscreen, no Powered Tonneau Cover for the truck bed, and no 120v/240v outlets.

Tesla brings closure to head-scratching Cybertruck trim

For just $10,000 more, at $79,990, owners could have received all of those premium features, as well as a more capable All-Wheel-Drive powertrain that featured Adaptive Air Suspension. The discount simply was not worth the sacrifices.

Orders were few and far between, and sources told us that when it was offered, sales were extremely tempered because customers could not see the value in this trim level.

Even Tesla’s most loyal supporters thought the offering was kind of a joke, and the $10,000 extra was simply worth it.

Cybertruck RWD Recall by Joey Klender

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