News
SpaceX’s Starship explosion explained by Elon Musk
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).
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.
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.
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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Investor's Corner
New drone video shows Tesla’s Optimus Factory reaching a turning point
New drone footage shows Tesla’s dedicated Optimus factory steel frame nearing completion at Giga Texas.
Tesla’s dedicated Optimus factory at Gigafactory Texas is closing in on a finished steel frame, according to drone footage posted Thursday afternoon by longtime site observer Joe Tegtmeyer. In the video, Tegtmeyer said structural steel assembly is now about five column grids away from reaching the building’s north perimeter beam, putting the primary skeleton in its final stretch roughly six months after Tesla broke ground on the North Campus site in late March.
The Giga Texas Optimus Factory latest update … construction keeps moving fast!
Steel assembly is now only about 5 column grids from the north perimeter beam. Concrete is going in on the three upper floors, rebar is still being laid for more pours, and footing / grade-beam work… pic.twitter.com/qvFPvwnYzW
— Joe Tegtmeyer 🚀 🤠🛸😎 (@JoeTegtmeyer) September 17, 2026
Tegtmeyer’s footage shows concrete already going in on three upper floors while crews continue laying rebar and pouring grade beam footings at ground level. That kind of parallel work, steel rising at one end of the site while concrete sets at the other, is a scheduling approach Tesla used at the original Giga Texas building and appears to be repeating here to save time before the plant’s targeted 2027 production start.
Teslarati has tracked the building’s progress since Tesla confirmed construction was officially underway in May, when the first steel structure went up on what was then bare, reclaimed land. The facility is part of a more than 5.2 million square foot expansion of Giga Texas’s North Campus that Tesla has said will eventually run nearly the length of the existing vehicle factory, over 4,000 feet, while sitting somewhat narrower. Musk has pegged the long term output target at 10 million Optimus units a year once the line is running at full capacity, a volume that would dwarf the one million unit pilot line Tesla is standing up separately at its Fremont, California factory.
Tesla Giga Texas to feature massive Optimus V4 production line
The Texas facility sits alongside another major buildout on the same campus. Terafab, the joint Tesla and SpaceX chip fabrication plant that will eventually supply the silicon running Optimus units in the field. Housing robot assembly and chip production on the same grounds is a deliberate supply chain decision, cutting down on the shipping and lead time that would otherwise sit between the two.
Tesla has not given an updated timeline beyond its previously stated goal of bringing high volume Optimus production online at the site in the summer of 2027. Fremont’s smaller pilot line began mass producing the current Gen 3 robot in January, with that plant expected to build tens of thousands of units this year primarily to generate the real world data Tesla needs to refine the robot’s software before Giga Texas ramps up. Six months of visible construction progress, tracked almost entirely through Tegtmeyer’s recurring drone flights, gives the clearest outside look yet at how seriously Tesla is treating that 2027 deadline.
Investor's Corner
Tesla and SpaceX take “Terafab” Trademark fight to Federal Court
Tesla and SpaceX sue a small Illinois firm after cease and desist letters over Terafab.
Tesla and SpaceX are asking a federal judge to rule that their planned Terafab chip factory does not infringe a small Illinois company’s trademark, a request that arrives only after months of quiet negotiation broke down this summer.
The dispute traces to May 18, when Tesla filed three U.S. trademark applications for “Terafab” and “Tesla Terafab,” covering semiconductor chips and related chip making services. TERA-print LLC, a nanotechnology company that has held a federal trademark for “Tera-Fab” since 2021, responded five days later with a cease and desist letter. According to the lawsuit, first reported by Reuters, TERA-print argued that Tesla and SpaceX’s use of “Terafab” would confuse consumers familiar with its own trademark, which covers a desktop photolithography printer sold to researchers for sensor and bioengineering work.
What stands out in the filing is the timing of TERA-print’s own paperwork. One day before sending that cease and desist letter, on May 22, TERA-print applied to expand its existing registration to cover semiconductor materials, silicon chips, nanoelectronic devices and AI design services, categories it had not previously claimed. Tesla and SpaceX call that filing opportunistic in their complaint, noting it arrived two months after Tesla’s public Terafab announcement and just days after Tesla’s own trademark applications went in.
Elon Musk launches TERAFAB: The $25B Tesla-SpaceXAI chip factory that will rewire the AI industry
By June 10, TERA-print was threatening to sue for federal trademark infringement, false designation of origin and unfair competition, the complaint states. Rather than wait to be sued, Tesla, SpaceX and SpaceXAI met with TERA-print six separate times between June and August trying to resolve the dispute directly. Those talks collapsed, and the companies filed for declaratory judgment this week in the U.S. District Court for the Western District of Texas, asking a judge to find that “Terafab” does not infringe TERA-print’s mark before TERA-print can file a claim of its own.
TERA-print isn’t backing down. The company told PCMag it discussed a settlement with Tesla as recently as September 2 and feels misled by what it called Tesla’s professed interest in settling. Its CTO, Andrey Ivankin, said TERA-print holds a Defense Department contract to fabricate semiconductors and partially owns Mattiq Inc., an AI company built on TERA-print’s products, and that the company will vigorously defend its rights.
Tesla and SpaceX argue the overlap is superficial. Terafab is planned as a $16.8 billion complex spanning roughly 100 million square feet at the Grimes County site SpaceX confirmed last month, built to produce chips for Optimus robots, Tesla’s AI computing needs and SpaceX’s orbital data center ambitions, a scale and purpose the companies say no reasonable consumer would confuse with a tabletop lab printer. TERA-print’s product line has stayed focused on lithography tools for biological and sensor research since it registered its mark in 2021.
The trademark fight is the second legal dispute tied to the Terafab project in the past week, following a separate SpaceX suit aimed at keeping company records about the facility out of public view, as KBTX reported. Whether construction proceeds under the Terafab name now depends on a federal judge in Austin.
News
NHTSA just escalated its Tesla Cybercab investigation in a big way
NHTSA escalated its Cybercab audit into a sworn Special Order with a September 30 deadline.
Federal regulators have moved from asking Tesla questions about its Cybercab to demanding sworn answers. The National Highway Traffic Safety Administration issued a Special Order that requires a Tesla officer to sign an affidavit attesting to the completeness of the company’s responses, with a deadline of September 30.
The order builds on Audit Query AQ26002, which NHTSA opened on September 3, the same day Tesla began commercial Cybercab service in Austin. Teslarati covered that initial inquiry when it surfaced, noting the agency wanted to understand how Tesla certified a vehicle with no permanently attached steering wheel, pedals, or mirrors as compliant with Federal Motor Vehicle Safety Standards. A Special Order is a different tool and converts a fact finding review into a legally enforceable demand, the same mechanism NHTSA used against Tesla in 2023 during its Autopilot investigation.
Several of the 21 requests target a specific gap in Cybercab’s design. One asks whether Tesla used temporarily attached human controls at any point to help certify the vehicle, and if so, which standards depended on that equipment being present. Another quotes an existing rule directly: “The service brakes shall be activated by means of a foot control.” Cybercab has no foot pedal. NHTSA wants a detailed explanation of how the vehicle satisfies that requirement, and how it complies without the kind of exemption granted to Zoox in July under Part 555, the regulatory pathway built for steering wheel free vehicles.
The order does not claim Cybercab is unsafe or that Tesla broke a rule. It requires Tesla to explain, under oath, the reasoning behind decisions the company already made when it self-certified the vehicle. That distinction matters, but so does the exposure. Motor1’s reporting, summarized here, put potential civil penalty exposure as high as $139 million if NHTSA later finds the certification was flawed, on top of whatever criminal risk comes with a false sworn statement.
Tesla has not said publicly how it plans to respond. Cybercab is still carrying passengers in Austin through the Robotaxi app while the September 30 deadline approaches, and the company has continued expanding the vehicle’s footprint even as the regulatory question remains open. The Special Order does not pause any of that and just sets a date by which Tesla has to put its certification logic on the record, with a company officer’s name attached to it.
New drone video shows Tesla’s Optimus Factory reaching a turning point
Tesla and SpaceX take “Terafab” Trademark fight to Federal Court
