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SpaceX is building Starship’s first orbital-class booster at a breakneck pace
Within the last week, SpaceX’s South Texas Starship factory appears to have kicked things into high gear and are now assembling the first orbital-class Super Heavy booster prototype at a breakneck pace.
While the assembly of the Super Heavy known as Booster 4 (B4) wasn’t too dissimilar to what CEO Elon Musk described as a “very hard” build of Booster 3 up to last week, work on the rocket has visibly accelerated. Since January 2020, the process of building Starships and Super Heavy boosters has been fairly simple. Both onsite and offsite, raw materials (mostly sheet steel) are cut, bent, and welded into relatively small parts that then make their way to (or around) Boca Chica by truck, forklift, or crane.
With the help of jigs and good amount of automation, the resulting hardware is then welded together to form domes, header tanks, transfer tubes, tank barrels, flaps, and more. Once subassembly is complete, those integrated rocket sections are reinforced with stringers, ribs, and baffles and outfitted with mechanisms, hardpoints, brackets, plumbing, and more. Finally, final assembly – better known as stacking and by far the most visible step – can begin and technicians stack each of those premade segments on top of each other to form a complete Starship or Super Heavy.
While part fabrication and subassembly integration take weeks or months on their own, those earlier steps can be done concurrently, meaning that SpaceX can prepare sections for several different ships and boosters at the same time. For the last six or so months, at any given moment, SpaceX has had 40-60+ rings in work as part of 15-20+ different ring ‘sections’ visible all across Starbase.
Respectively, each Starship and Super Heavy booster require 20 and 36 rings apiece, while each of the propellant storage tanks SpaceX itself is building for the rocket’s first orbital launch pad require 12-15. All told, SpaceX usually has a combination of around 3-5 ships, boosters, and GSE tanks in some stage of assembly. Unsurprisingly, some assembly tasks are harder than others and building the first in a series of prototypes has almost invariably taken far longer than building those that follow.
Booster 3 Booster 4 LOx tank start May 20th July 16th LOx tank finish June 18th July 30th CH4 tank start June 24th July 28th CH4 tank finish June 27th July 29th Final stack June 29th Aug 1st?
In that sense, it’s not a huge surprise that SpaceX’s Booster 4 assembly has quickly surpassed the pace set with Booster 3 less than a month earlier. SpaceX began stacking Super Heavy B3 around May 20th, starting with the rocket’s aft liquid oxygen (LOx) tank. Five separate stacks are required to turn the LOx tank’s 23 steel rings into a single structure – a process that took SpaceX about a month with Booster 3.
Booster 3 methane (CH4) tank assembly began a few days after the LOx tank’s completion but proceeded far more quickly, wrapping up just a few days later. Two days after that, those two tank sections were then mated and welded together to complete Booster 3’s full ~65m (~210 ft) tall airframe.
Now, just four weeks after Booster 3 was rolled to the launch pad for proof and static fire testing, Super Heavy Booster 4 is well on its way to reaching its full ~65m height almost twice as quickly. With work beginning around July 16th, B4’s oxygen tank is now just missing an (extremely complex) engine section and the booster’s methane tank was stacked to completion – 13 rings tall – in less than two days. That leaves SpaceX’s first potentially flightworthy, orbital-class Super Heavy booster just two stacks away from completion less than two weeks after its assembly began.
If SpaceX can sustain that pace for another few days, Booster 4 assembly will be the fastest of any full-height prototype ever built at Starbase, most of which have been Starship prototypes that are half to about three quarters the size of Super Heavy.
SpaceX is preparing for the 13th integrated flight test of its Starship system, with a targeted launch as early as Thursday, July 16. The 90-minute launch window opens at 5:45 p.m. CT from Starbase in South Texas.
This comes roughly seven weeks after Flight 12 on May 22, underscoring the company’s accelerating pace in its rapid development campaign. The mission will use the latest Starship and Super Heavy V3 vehicles equipped with Raptor 3 engines. Booster 20 will attempt a controlled boostback burn, followed by a splashdown in the Gulf of Mexico, while Ship 40 will follow a suborbital trajectory.
Starship’s thirteenth flight test is preparing to launch as early as Thursday, July 16 → https://t.co/Rp7VwBzpWx pic.twitter.com/jdpFlQUEpF
— SpaceX (@SpaceX) July 11, 2026
Key objectives for Flight 13 will include demonstrating reliable stage separation, engine performance under various conditions, and controlled reentry.
A major milestone for Flight 13 is the first deployment of 20 next-generation Starlink V3 satellites. These satellites feature advanced laser links for inter-satellite communication, deployable solar arrays, and onboard cameras, six of which will capture imagery of Starship’s heat shield during flight.
Several heat shield tiles on Ship 40 will be painted white to serve as imaging targets, while additional experiments test upgraded tiles on aft flaps, modified attachments on the aft skirt, and load-sensing tiles to measure stresses. The upper stage will also attempt a single Raptor engine relight in space before a targeted splashdown in the Indian Ocean.
These tests build directly on lessons from Flight 12, which introduced the V3 configuration but encountered issues including a booster flip anomaly during boostback and an engine-out event on the ship. Hardware and software modifications on Booster 20 and Ship 40 aim to improve engine relight reliability, startup sequencing, and overall robustness.
Next Starship launch aiming for Thursday https://t.co/SajPPd4pdb
— Elon Musk (@elonmusk) July 12, 2026
The short interval between Flights 12 and 13 highlights SpaceX’s iterative approach. Elon Musk has repeatedly emphasized that Starship launches will become “incredibly common” in the coming years.
The company envisions scaling to rates as high as one launch per hour within 4-5 years, potentially enabling thousands of flights annually. Such cadence is essential for Starship’s goals: establishing orbital refueling for lunar and Mars missions, deploying massive satellite constellations, and making life multiplanetary.
With each flight, Starship edges closer to full reusability and operational maturity. Success on July 16 would mark another step toward routine access to space and the ambitious vision of humanity becoming a spacefaring civilization.
Tesla shared a striking video showcasing the decommissioning of the original Model S and Model X assembly line at its Fremont Factory in Northern California. Completed in just 46 days, the teardown involved heavy machinery dismantling concrete pits, removing robotic arms and conveyors, and clearing the space for new production.
The post, captioned “End of an era,” captured both the end of a historic chapter and Tesla’s aggressive pivot toward its next major initiative, Optimus.
End of an era: Decommissioning the original Model S & X assembly line in just 46 days pic.twitter.com/kGEdfhl62h
— Tesla Manufacturing (@gigafactories) July 10, 2026
The decision to retire the Model S and Model X originated during Tesla’s Q4 2025 Earnings Call in late January 2026. CEO Elon Musk announced that production of the company’s flagship sedan and SUV would wind down by the end of Q2 2026, describing it as bringing the programs to an “honorable discharge.”
Custom orders ceased around early April 2026, with the final vehicles rolling off the line in early May. A special signature delivery ceremony on May 20 marked the emotional close for these vehicles, which had defined Tesla’s early success and luxury EV segment since the Model S launch in 2012.
The primary reason for tearing down the lines was to repurpose the valuable factory floor space for high-volume production of Tesla’s Optimus humanoid robot. Musk had indicated on Earnings Calls that the Fremont S/X line would be replaced by a dedicated Optimus manufacturing line targeting a capacity of one million units per year.
This move aligns with Tesla’s broader strategic shift from traditional vehicle manufacturing toward robotics and artificial intelligence, leveraging the company’s expertise in autonomy, AI training, and high-volume production.
Optimus, Tesla’s general-purpose humanoid robot, is designed to perform repetitive or dangerous tasks in factories, warehouses, and eventually homes. Powered by Tesla’s AI and Neural Networks, it aims to be a versatile, affordable platform. Production of Optimus Gen 3 is already underway in limited form at Fremont, with full-scale output on the converted line expected to begin in late July or August.
Tesla is targeting rapid scaling, with internal ambitions pointing toward tens or even hundreds of thousands of units annually by the end of 2026.
Longer-term, Tesla is constructing a much larger second-generation Optimus facility at Giga Texas, with potential capacity reaching millions of units per year. The company views Optimus as a transformative product that could eventually surpass its automotive business in scale and value, enabling widespread deployment of useful robots across industries. CEO Elon Musk has even predicted it would be the most popular product of all-time.
As one era closes at Fremont, another is rapidly taking shape.
Elon Musk posted a candid admission on his social media platform X on June 9, declaring that he had been “clearly wrong” about Anthropic. The statement marked a notable reversal from his earlier skepticism toward the AI company.
In September, Musk had written, “Winning was never in the set of possible outcomes for Anthropic,” reflecting his view at the time that the startup had lacked the foundation or even the trajectory to succeed in what is an incredibly intense race for advanced artificial intelligence.
Musk’s latest post came amid discussion of Anthropic’s reliance on external compute resources. He praised the company’s progress, stating that Anthropic is “obviously currently the leader in AI” and that “no company has released a model as good as Mythos/Fable,” with expectations of a strong follow-up in Mythos 2.
The tone shifted dramatically from dismissal to acknowledgement of superior performance.
I was clearly wrong about Anthropic. They are obviously currently the leader in AI. No company has released a model as good as Mythos/Fable and they will undoubtedly have Mythos 2 ready soon.
And I would never cut them off in a way that hurt them badly, even as a competitor.…
— Elon Musk (@elonmusk) July 9, 2026
The context of Musk’s comments added significance. Anthropic has been operating under a recent compute deal with SpaceXAI, Musk’s AI infrastructure-focused venture. The pair entered a short-term GPU lease agreement initiated in May, providing Anthropic access to critical computing power for training and deploying its frontier models.
SpaceXAI signs agreement with Anthropic for massive AI supercomputer access
Some observers had speculated that Musk could leverage this dependency to disadvantage a rival. Musk directly addressed the possibility, writing, “I would never cut them off in a way that hurt them badly, even as a competitor. That’s not my style.”
To support his commitment to ethical competition, Musk referenced concrete examples from his other companies. Tesla famously open-sourced its entire portfolio of electric vehicle patents in 2014. The move was designed to accelerate the global adoption of sustainable transportation technology rather than protect proprietary advantages.
Tesla also made its Supercharger network available to competing electric vehicle manufacturers, transforming what could have remained an exclusive charging ecosystem into a shared infrastructure that benefits the broader industry and reduces barriers for EV adoption.
Musk further pointed to SpaceX’s practices, noting that the company launches satellites for competing commercial systems “with no increase in price or use of unfair terms.” He extended the principle to his social platform, observing that “even my worst enemies attack me on this platform,” underscoring preference for open discourse over retaliation.
These examples have illustrated Musk’s long-standing philosophy that long-term technological progress is best served by open competition and infrastructure sharing rather than leveraging market power to stifle rivals. In the fast-evolving AI sector, where compute resources and model capabilities determine leadership, Musk’s stance suggests a willingness to compete on innovation and performance alone.
Musk’s admission arrives as SpaceXAI itself advances its own frontier models while maintaining business relationships across the ecosystem. By publicly correcting his earlier assessment and reaffirming principles of fair play, Musk highlights a model of competition that prioritizes advancement of the field over short-term tactical advantages.
SpaceX reveals Starship Flight 13 launch date
Tesla shows rapid teardown of Model S and X lines, paving the way for Optimus at Fremont
