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SpaceX rolls Super Heavy booster to orbital launch mount
For the third time in four months, SpaceX has rolled the first potentially flightworthy Super Heavy booster towards Starbase’s orbital launch mount.
Combined with a large crane – fitted with a jig solely used to lift boosters – moving to a spot just beside the booster, it’s clear that SpaceX is preparing to reinstall Super Heavy Booster 4 (B4) on the orbital launch mount. In the context of its unusual history, though, what happens next to the first more or less finished prototype of the largest rocket booster ever built is less clear.
After a shockingly quick assembly over the course of six summer weeks, Super Heavy Booster 4 rolled out of Starbase’s ‘high bay’ facility and headed to the nearby orbital launch complex, where it was installed on a custom ‘mount’ designed to support booster testing and orbital launches. It’s now clear that during that early August photo opportunity and fit test, Booster 4 was nowhere close to finished. Nor, apparently, was it anywhere close to complete one month later when it returned to the orbital pad for the second time after another few weeks of work back at the high bay.
Three months (almost 14 weeks or 100 days) after the Super Heavy prototype’s second trip to the pad, SpaceX has yet to attempt to put the booster through a single proof test. There also appears to be a significant amount of work left to finish installing external ‘aerocovers’ and a heat shield meant to enclose all 29 of its Raptor engines. In the three-year history of Starbase, there isn’t a single prototype of the roughly two-dozen SpaceX has built, tested, and even flown that’s spent even half as long as Super Heavy B4 between apparent structural completion and its first test. Perhaps the fact that Booster 4 is a first-of-its-kind pathfinder explains SpaceX’s uncharacteristic sluggishness or reluctance to actually test the rocket.
In every other instance, SpaceX’s approach to Starship development has been to move incredibly quickly, build a large number of prototypes, and rapidly test those prototypes – often resulting in catastrophic failures. Data is gathered from those failures (SN1, SN3, SN4, SN8, SN9, SN10, SN11, and half a dozen smaller test tanks serve as examples), changes are made, and then the new and improved prototypes that follow repeat the process until SpaceX arrives at a successful design.
Super Heavy B4’s circuitous path has been almost nothing like those of its predecessors. That could also be partly explained by the unavailability of a stand or facilities capable of truly proof testing a Super Heavy, which necessitates a supply of around 3200 tons (7M lb) of liquid nitrogen (LN2; for a cryogenic proof test with full tanks), another 3200 tons of a combination of liquid methane (LCH4) and oxygen (LOx), and the ability to ignite – and survive – as many as 29 to 33 Raptor engines. The suborbital stands SpaceX has used to proof Starships and even Super Heavy Booster 3 don’t even have half the storage capacity required to fully test a booster and the mounts and their surroundings would likely be catastrophically damaged or destroyed by the thrust and blast created by dozens of Raptors.
Still, SpaceX could have theoretically put Booster 4 through a partial cryoproof and maybe fired up as many as nine Raptors at once – not a replacement for full proof testing but still plenty to ensure Super Heavy’s structural integrity and gather invaluable data on clustered Raptor performance. Instead, of course, Super Heavy B4 has sat at Starbase’s former landing zone for more than three months while teams removed engines, reinstalled engines, half-installed a full Raptor heat shield; and installed two of six or seven ‘aerocovers’ needed to protect heat exchangers, racks of pressure vessels, and hydraulic systems installed on the booster’s aft.
This is all to say that from the outside looking in, Booster 4’s path towards testing and flight has been almost entirely different from that of any other Starship prototype. While still quick in comparison with other launch vehicle development programs, relative to other Starship and Super Heavy prototypes, the rate of B4 progress has been far slower – strongly implying that something is seriously wrong with the booster, that SpaceX no longer feels that partial testing is worth the effort, that finishing Booster 4 just hasn’t been a priority for several months, or some combination of the above.
What that ultimately means is that it’s almost impossible to predict what Super Heavy B4’s future holds beyond the clear evidence that SpaceX will soon reinstall to reinstall it on an orbital launch mount that’s much closer to completion than it was the last time B4 was installed. At this point, it’s just as likely that the booster’s third launch mount installation will just be another mechanical fit test, though the hope is that it will kick off full-scale pneumatic and cryogenic proof testing. It could even culminate in the static fire of some or all of its 29 Raptor engines, which have been installed for several months.
A Tesla Semi caught fire in Hayward, California, which caused both directions of traffic to shut down for hours before being completely reopened early on Wednesday, the California Highway Patrol said.
The fire occurred just after 5:30 local time in Hayward on Tuesday, as the Semi caught fire in the southbound lanes of I-880 before CHP officials made the decision to shut down both lanes of traffic due to potential risks from hazardous chemical smoke.
There were no injuries reported.
🚨 A Tesla Semi reportedly caught fire, with California Highway Patrol confirming. The Semi was on I-880 SB
An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year
— TESLARATI (@Teslarati) October 28, 2026
The cause of the fire is currently unknown, as neither Tesla nor the CHP have not determined a cause.
However, some images taken before the Semi was completely destroyed by the fire seem to indicate this might have been an older unit, as it appears to be one of the designs that Tesla shipped as part of its pilot program, before revising it and starting mass production just a month ago.
@Tslachan From on of the videos looks like it’s an old Semi (not the refresh version that recently started production) https://t.co/KzwmR2kXow
— Area Under The Curve 🎗️ (@AreaUnderCurve) October 28, 2026
At the time of publication, CHP had not returned our request for a comment for additional details, including the Semi involved and any potential collaboration on an investigation between the CHP and Tesla. We will update this story when we hear back from them.
The southbound lanes were reopened at 3:30 a.m. on Wednesday, with the northbound lanes opening last night a few hours after the fire began. The CHP did state that the lithium batteries were “incredibly difficult to extinguish,” according to NBC Bay Area.
The truck’s driver said that the Semi caught fire, but he did not have an explanation.
An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year.
Tesla’s launch of the “Emergency Drive Away” function a few months back offered owners a safe option to evacuate an area if they were in reasonable danger. The function finally got its first use in the real world, but it appears it was by mistake.
A video shared by u/Joshalander in the r/TeslaLounge subreddit recorded the instance from his vehicle and said the incident took place in Austin this past weekend during the city’s F1 Race.
“Was charging around 6 AM this past Sunday in Austin before heading to the F1 race and heard a pop. Looked over and saw the new emergency drive-away feature in action. Genuinely felt bad for the dude when he got out and realized what happened, since he looked exhausted and only seemed to half-read the prompts.”
🚨 Here’s the first look at Tesla’s Emergency Drive Away function in action:
Apparently this driver accidentally enabled it and drove forward; you can see the Supercharger pull with the car.
Tesla said previously this would cost up to $25k if not used properly. https://t.co/B4qQRrsO6B
— TESLARATI (@Teslarati) October 28, 2026
Emergency Drive Away unlatches the Supercharger connector from the vehicle, but still causes damage to both the car and the Supercharger. Tesla has said that it will cost up to $25,000 in repairs to have everything fixed back to normal.
Additionally, the company said that if it were not used in an emergency situation, the driver of the vehicle who activated the Emergency Drive Away feature would be responsible for all repair costs.
Tesla constitutes the following situations as reasonable justifications for activating the feature:
- You face an immediate threat to your life or personal safety.
- You must leave the area immediately.
- Exiting the vehicle is unsafe.
- Unplugging the charge connector would unreasonably delay your departure or expose you to a risk to your personal safety.
After using the feature, Tesla requires the driver to schedule Service so the car can be inspected.
News
Tesla’s Cybercab battery design could make robotaxis even cheaper
Tesla built the Cybercab’s battery pack with spare room for a future switch to LFP.
Tesla built the Cybercab’s battery pack with empty space inside it on purpose, and the reason points to a cheaper robotaxi down the road.
Robert Sumpf, Tesla’s director of mechanical design engineering for battery modules and packs, said the extra room beside and beneath the Cybercab’s modules was left there so the company can move to lithium iron phosphate cells later. “So, we protected this pack to go to an even lower energy dense chemistry as we scale and need to bring LFP into the platform,” Sumpf said in a Cybercab deep dive with Munro Live.
The Cybercab runs on Tesla’s own 4680 cells with a nickel chemistry today. LFP cells store less energy for their size, so a straight swap would cut range. The reserved space lets Tesla add more LFP cells to make up the difference. In return, Tesla would get cells that cost less, run cooler and survive more charge cycles. LFP became the most used EV battery chemistry in the world last year.
Not all of that room was planned for a chemistry change. Lars Moravy, Tesla’s Vice President of Vehicle Engineering, said part of it exists because “we didn’t need as many batteries as we thought we did.” Tesla told Sandy Munro in early 2025 that it was targeting a Cybercab pack under 50 kWh with close to 300 miles of range.
The pack also breaks from the structural design Tesla used in some Model Y and Cybertruck builds. Instead of potting hundreds of cells into one block, the Cybercab uses four separate, individually sealed modules, so a bad module can be replaced without scrapping the whole pack. Sumpf was blunt about the older approach, giving the Model Y structural battery “a grade D” because it was hard to build and nearly impossible to repair. He estimated a fully structural pack gains about 10% more cell volume, but said “the issue is the service cost.”
That cost matters more for a car that rarely sits parked. Cybercab chief engineer Eric Earley said replacing an entire pack “before half a million miles is a killer on cost,” which is why remanufacturing and serviceability were built into the design from the start.
The same Munro Live tour produced Moravy’s admission that the Cybercab line at Giga Texas is now outpacing Robotaxi deployments, along with a look at the robotaxi’s unorthodox paint process. Tesla is aiming to deliver the first Cybercabs to outside customers by the end of 2026, though Elon Musk has said the vast majority will stay owned by Tesla and run as a transport service.
Sumpf did not give a date for an LFP version, name a cell supplier or say how a chemistry change would affect range. For now, the 4680 cars keep piling up: Texas DMV records from Tuesday list 544 Cybercabs authorized for Tesla’s Robotaxi fleet, more than the 507 Model Ys on the same roster for the first time.
Tesla Semi catches fire in California: what we know
Tesla’s ‘Emergency Drive Away’ function gets its first use in the real world
