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SpaceX's Elon Musk works through holidays on Starship's "most difficult part"
SpaceX CEO Elon Musk says he has been working through the holidays at the company’s Boca Chica facilities to get Starship’s “most difficult part” ready for the next-generation spacecraft’s next prototype and flight tests.
Known as tank domes or bulkheads, Musk says that the hardware is the most difficult part of building and assembly Starship’s primary structure, referring to the steel engine section, tanks, and pointed nose that comprise most of the spaceship’s body. Starship’s primary structure must stand up to the rigors of all aspects of flight, including highly-pressurized propellant tanks, extreme G-forces during launches, orbital reentry, and more.
It was never officially determined whether the failure was intentional or not but during the first Starship prototype’s (Mk1) last test campaign, the vehicle experience an overpressure event while being filled with liquid oxygen or nitrogen. Localized to the weld connecting the upper tank dome to Starship’s cylindrical tank section, the dome essentially sheared off at the weld and launched hundreds of feet into the air, sending a shockwave through the vehicle that crumpled many of its steel structures as if they were aluminum foil.
It’s likely that Starship Mk1’s failure was an intentional overpressure event, meaning that SpaceX may have purposely pressed the vehicle’s tanks beyond their design limits to determine how structurally sound they were. What is less clear is whether the rocket burst before or after reaching its theoretical design limit.
For reference, SpaceX’s Falcon 9 rocket operates with its fuel and oxygen tanks pressurized to about 50 psi (3.5 atm) with localized pressures likely doubling or tripling near the bottom of both tanks during the first minute or two of launch. Some amateur back-of-the-envelope calculations from videos of Starship Mk1’s burst event suggest that it was pressurized to at least 60-75 psi (4-5 atm) at its upper tank dome, meaning that the pressure on its two lower domes and tank walls would have been even higher. If correct, those unofficial figures mean that Mk1 actually performed quite well considering the ramshackle facilities and unprecedentedly spartan methods used to fabricate and assemble it.
As such, Musk likely considers Starship’s tank domes the “most difficult part of [its] primary structure” in large part because of how difficult it is to make giant propellant tank domes simultaneously light and strong. Musk has previously implied that Starship Mk1 was more 200 tons (450,000 lb) empty while the ultimate goal for the spacecraft’s empty weight is closer to 120 tons, and a large portion of that weight savings will likely have to come from making its tank domes as light as possible.
In line with that educated speculation, the last month or so of SpaceX’s Starship work in Boca Chica, Texas has been marked by a distinct focus on building tank domes. In fact, Musk himself tweeted that he had worked all night with SpaceX engineers in Boca Chica in a bid to get dome production ready for Starship’s Mk3 prototype, the first Super Heavy hardware, and many more rockets to come.
Prior to Musk’s tweet, a Starship tank dome was actually shipped all the way from Florida to Texas and arrived earlier this month. Meanwhile, technicians have been briskly building up an additional dome using what appears to be a different method of integration involving new parts. SpaceX is currently attempting to weld Starship’s tank domes together from several dozen pre-formed sheets of stainless steel.
The sheets of steel assembled into the dome Musk showed on December 27th likely arrived in Boca Chica on December 13th, implying that SpaceX has managed to complete the majority of the first dome prototype – using a new process – in barely two weeks.
After SpaceX lifted the partially-completed dome off one of its custom assembly jigs, workers almost instantly began staging new sections of steel, beginning the process of integrating yet another tank dome – now likely the fourth on-site in Boca Chica. Meanwhile, at a nearby section of SpaceX’s Boca Chica production facilities, yet another dome was visible on the 28th. In short, SpaceX should soon have more than enough tank domes to complete the next Starship prototype – said to be a significantly improved and refined design compared to Mk1.
Known as Starship Mk3 (or Starship SN01), Musk says that the rocket – currently just a miscellaneous collection of separate parts – could (“hopefully”) be ready for its first flight as soon as February or March 2020.
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Tesla is set to inaugurate its dedicated Semi factory in Sparks, Nevada, this evening, but drone footage has already started to show who is expected on the handover stage.
Zanegler, a drone operator who regularly documents Tesla Semi operations in Nevada, filmed a row of new-generation Semi units parked outside of the plant with customer branding applied. The liveries visible in the video include companies like PepsiCo, U.S. Foods, Einride, DHL, WattEV, and others that have committed to utilizing Tesla’s Class 8 electric truck in their fleets.
Tesla Semi Pre-Reveal Revealed!
Excited to share this segment of the drone flight one day prior to the Tesla Semi Reveal event.
They have added branding to several Tesla new generation semis.
Including:
Pepsico
US Foods
Einride
LTS
Nevoya
OK Produce
ABF Freight
DHL
WattEV… pic.twitter.com/KoFOg2FouR— Zanegler (@HinrichsZane) September 24, 2026
Several of those company names already sit within Tesla’s public ordering book, including PepsiCo, which has been the program’s primary anchor customer since the first Semi deliveries in December 2022. PepsiCo now runs dozens of Tesla Semi units in daily service, with drivers completing regional routes.
Einride placed a 500-unit order in August, which was, at the time, the largest single Semi commitment. First deployments of their Semi units are planned for this month and will eventually span across California, Texas, New Jersey, Illinois, and Georgia. Meanwhile, IMC Logistics announced a 50-truck California order this week.
Tesla Semi lands the biggest electric truck deal in U.S. history
Other names, like LTS, OK Produce, and HMD, have not been widely confirmed as firm buyers, but their presence on the lot is perhaps the clearest signal that Tesla intends to expand on that list this evening at the event.
Tesla first unveiled the Semi back in 2017 with a 2019 production target.
Limited pilot builds reached PepsiCo in late 2022, and high-volume production began at the new 1.7-million-square-foot plant that sits logically positioned next to Tesla’s Gigafactory Nevada. Tesla Semi program director Dan Priestley has said that Tesla expects to build “many thousands” of Semi units this year, but as with every Tesla release, there have been set expectations of an S-curve ramp.
Outside estimates still put 2026 deliveries in the 5,000-to-15,000 range, but it will ultimately depend on Tesla’s readiness to put those units out, as well as how smoothly production is moving internally.
Tesla’s Semi Rollout event is set to start tonight at the Sparks factory, and it will be livestreamed on X starting at 6 p.m. PDT / 9 p.m. ET.
The Tesla App is now giving owners a better indication of what to expect when visiting a Supercharger site, as it is now sharing Site Maps in the app itself, making the feature no longer exclusively available in the car.
Tesla owners can now preview a Supercharger’s layout and live stall status from their phone thanks to the App’s new software version, v4.61.0. Zooming into a supported Supercharger on the charging map now switches the familiar street view into a site-specific map that shows stall positions, occupied bays, out-of-service posts, and a live count of open Superchargers.
It will even show you which specific Tesla model is charging at each occupied stall.
You can now see Live Site Maps in the latest Tesla app (4.61.0.) pic.twitter.com/JIL8QzR8hu
— Zack (@BLKMDL3) September 18, 2026
This is the same view drivers first saw inside the car with the 2025 Holiday Update, which started as a pilot for Tesla in California and Texas. Those early maps showed layout, nearby amenities, and the status of each operational stall. The feature has spread to most Superchargers in the U.S., but now Tesla wants the feature available through the Smartphone App, which is now rolling out to owners.
The in-vehicle screen maps remain a richer 3D canvas and originally required AMD Ryzen infotainment hardware, which left many Intel-based Model 3 and Model Y owners without the view. The app version removes that hardware barrier, so any owner can now get a preview of their upcoming Supercharger stop on their phone.
Anyone with the updated version of the app can open a Site Map on their phone. The feature has provided some additional peace of mind to anxious travelers and those who might be looking for a place that is less congested for faster charging speeds. It is a meaningful addition to many owners, especially for trips to unfamiliar locations.
You can now pick a Supercharger location that might be more aligned with what you are looking for or need: you can pick a site based on what stalls are open, where ADA stalls sit, how you will pull in, and more, instead of circling a crowded lot after arriving. Owners of older cars now have access to the feature without having to purchase a new vehicle altogether.
Site Mpas will not reserve a stall, nor will it change how Fast Charging works. Tesla does something simpler and more useful by giving owners a dedicated preview of the Supercharger they’re about to charge, turning an unknown parking lot into a place that may seem more familiar thanks to the preview.
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Investor's Corner
Tesla Optimus Gen 3 shows off a cleaner, factory-ready design in new app discovery
Renders hidden inside Tesla’s Android app show Optimus Gen 3’s design before any official reveal.
![Tesla Optimus Gen 3 [Credit: Tesla]](https://www.teslarati.com/wp-content/uploads/2026/03/tesla-optimus-gen3-diner.jpg)
Tesla may have accidentally given a first look at its newest Optimus Gen 3 humanoid robot when photos were found in the Tesla smartphone app.
Design files tucked inside a recent Android version of the Tesla app appear to show the third generation humanoid robot next to the older Gen 2.5 prototype. The assets were extracted from the app package by Tesla community member @wholemars, who posted the renders on X late Tuesday night before deleting them. The Tesla Newswire reshared the side by side comparison on Wednesday, and the images have circulated widely since.
Tesla Optimus Gen 2.5 vs Gen 3 comparison via @WholeMars on X
The files are labeled “gen3” and were built as models for Tesla app’s own interface, as validated directly by Grok to be official.
The comparison shows a robot that looks built for a factory line rather than a lab bench. Gen 2.5’s exposed mechanical linkages and gold plating on the knees and shins are gone. In their place, Gen 3 uses matte black fairings on the lower legs, paired with a more contoured champagne gold body. Flexible covers now seal the joint where the torso meets the upper thighs, keeping bearings and moving parts sealed from debris and unnecessary contact.
The body panels fit more tightly, and the hands, which Tesla has said carry 22 degrees of freedom, look far more refined than those on earlier units.
This most recent leak fills a gap Tesla has left open for most of the year. Elon Musk said on March 31 that Optimus 3 was walking around but needed “some finishing touches” before it could be shown, a delay Teslarati covered when Tesla missed its first quarter reveal target. Musk later said Tesla would hold the design back until closer to production, partly to keep competitors from copying it. No reveal date has been announced.
The app itself has been preparing for Optimus for months. In July, code in the Tesla app pointed to a dedicated robot phone key, a consent screen for collecting video and spatial data while Optimus works inside a home, and an alert system for low battery and mechanical faults. Finished 3D models of Gen 3 suggest the interface owners will eventually use is moving past placeholder code toward something Tesla intends to ship.
Manufacturing is moving in parallel. Tesla tore out the original Model S and Model X lines at Fremont this summer to make room for Optimus production, with a planned capacity of one million robots a year. At Giga Texas, the steel frame of a dedicated Optimus factory is nearing completion ahead of a targeted 2027 start, with Musk pointing to an eventual output of 10 million units annually.
Tesla drops big hints ahead of Semi handover event
Tesla App now shows you what your Supercharger will look like upon arrival
![Tesla Optimus Gen 3 [Credit: Tesla]](https://www.teslarati.com/wp-content/uploads/2026/03/tesla-optimus-gen3-diner-80x80.jpg)
