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SpaceX stacks first Super Heavy, creating largest rocket booster ever built
For the first time ever, SpaceX has stacked a Super Heavy tank section to its full height, effectively completing assembly of the largest rocket booster ever built.
While a good amount of work still remains to weld the two halves together and connect their preinstalled plumbing and avionics runs, those tasks are largely marginal and will tweak the massive steel tower that’s now firmly in one piece. Comprised of 36 of the steel rings also used to assemble Starships, the first Super Heavy prototype – serial number BN1 – will stand roughly 67 meters (220 ft) tall from the top of its uppermost ring to the tail of its soon-to-be-installed Raptor engines.
At that height, Super Heavy BN1 is just 3 meters (~10 ft) shorter than an entire two-stage Falcon 9 or Falcon Heavy rocket – the second and third tallest operational rockets today. Of course, Super Heavy is just a booster and SpaceX says the rocket will stand at least 120m (~395 ft) tall with a Starship upper stage and spacecraft installed on top, easily making it the tallest (and likely heaviest) launch vehicle ever assembled.
Notably, Super Heavy BN1 isn’t fully representative of the boosters that will support Starship’s first orbital launch attempts. For unknown reasons, SpaceX appears to have forgone the installation of any kind of landing legs on the first pathfinder and prototype. CEO Elon Musk has expressed a desire to avoid the need for legs entirely by catching Super Heavy boosters (and possibly even Starships) with a tower outfitted with giant arms, but it’s virtually impossible to imagine that such a wholly unproven recovery mechanism will be ready for full-scale testing – let alone operational use – later this year.
First reported by NASASpaceflight and later confirmed by Musk himself, SpaceX hopes to be ready to begin orbital Starship launches as early as July 2021, just four months from now. Per NASASpaceflight, that first launch attempt will nominally use Super Heavy booster BN3 and Starship SN20. Super Heavy BN1 is expected to remain grounded, serving as a testbed for inaugural pressure and proof tests, as well as one or several possible Raptor static fires (Update: confirmed by Musk).
If that process goes according to plan, Super Heavy BN2 will pick up where BN1 leaves off and attempt at least one short hop test, among other qualification tasks. In the interim between that feat and Super Heavy BN3’s launch preparations, it’s safe to assume that either BN2 or BN3 will support some kind of iterative static fire test campaign similar to what SpaceX once did with Falcon 9, gradually building up from tests with a half-dozen or so engines to static fires with 20 or more – possibly up to and including a full complement of 28 Raptors.
The first of its kind, booster BN1’s ‘thrust donut’ – a donut-shaped plate for the rocket’s center cluster of Raptor engines to attach to – appears to have been outfitted with hardware for four engines, suggesting a ceiling for static fire tests. It’s unclear when Super Heavy will roll to the launch pad for testing but it’s safe to say that SpaceX probably wont wait long after Starship SN11 is done with its high-altitude launch campaign. Stay tuned for updates!
News
Tesla confirms that it finally solved its 4680 battery’s dry cathode process
The suggests the company has finally resolved one of the most challenging aspects of its next-generation battery cells.
Tesla has confirmed that it is now producing both the anode and cathode of its 4680 battery cells using a dry-electrode process, marking a key breakthrough in a technology the company has been working to industrialize for years.
The update, disclosed in Tesla’s Q4 and FY 2025 update letter, suggests the company has finally resolved one of the most challenging aspects of its next-generation battery cells.
Dry cathode 4680 cells
In its Q4 and FY 2025 update letter, Tesla stated that it is now producing 4680 cells whose anode and cathode were produced during the dry electrode process. The confirmation addresses long-standing questions around whether Tesla could bring its dry cathode process into sustained production.
The disclosure was highlighted on X by Bonne Eggleston, Tesla’s Vice President of 4680 batteries, who wrote that “both electrodes use our dry process.”
Tesla first introduced the dry-electrode concept during its Battery Day presentation in 2020, pitching it as a way to simplify production, reduce factory footprint, lower costs, and improve energy density. While Tesla has been producing 4680 cells for some time, the company had previously relied on more conventional approaches for parts of the process, leading to questions about whether a full dry-electrode process could even be achieved.
4680 packs for Model Y
Tesla also revealed in its Q4 and FY 2025 Update Letter that it has begun producing battery packs for certain Model Y vehicles using its in-house 4680 cells. As per Tesla:
“We have begun to produce battery packs for certain Model Ys with our 4680 cells, unlocking an additional vector of supply to help navigate increasingly complex supply chain challenges caused by trade barriers and tariff risks.”
The timing is notable. With Tesla preparing to wind down Model S and Model X production, the Model Y and Model 3 are expected to account for an even larger share of the company’s vehicle output. Ensuring that the Model Y can be equipped with domestically produced 4680 battery packs gives Tesla greater flexibility to maintain production volumes in the United States, even as global battery supply chains face increasing complexity.
Elon Musk
Tesla Giga Texas to feature massive Optimus V4 production line
This suggests that while the first Optimus line will be set up in the Fremont Factory, the real ramp of Optimus’ production will happen in Giga Texas.
Tesla will build Optimus 4 in Giga Texas, and its production line will be massive. This was, at least, as per recent comments by CEO Elon Musk on social media platform X.
Optimus 4 production
In response to a post on X which expressed surprise that Optimus will be produced in California, Musk stated that “Optimus 4 will be built in Texas at much higher volume.” This suggests that while the first Optimus line will be set up in the Fremont Factory, and while the line itself will be capable of producing 1 million humanoid robots per year, the real ramp of Optimus’ production will happen in Giga Texas.
This was not the first time that Elon Musk shared his plans for Optimus’ production at Gigafactory Texas. During the 2025 Annual Shareholder Meeting, he stated that Giga Texas’ Optimus line will produce 10 million units of the humanoid robot per year. He did not, however, state at the time that Giga Texas would produce Optimus V4.
“So we’re going to launch on the fastest production ramp of any product of any large complex manufactured product ever, starting with building a one-million-unit production line in Fremont. And that’s Line one. And then a ten million unit per year production line here,” Musk stated.
How big Optimus could become
During Tesla’s Q4 and FY 2025 earnings call, Musk offered additional context on the potential of Optimus. While he stated that the ramp of Optimus’ production will be deliberate at first, the humanoid robot itself will have the potential to change the world.
“Optimus really will be a general-purpose robot that can learn by observing human behavior. You can demonstrate a task or verbally describe a task or show it a task. Even show it a video, it will be able to do that task. It’s going to be a very capable robot. I think long-term Optimus will have a very significant impact on the US GDP.
“It will actually move the needle on US GDP significantly. In conclusion, there are still many who doubt our ambitions for creating amazing abundance. We are confident it can be done, and we are making the right moves technologically to ensure that it does. Tesla, Inc. has never been a company to shy away from solving the hardest problems,” Musk stated.
Elon Musk
Rumored SpaceX-xAI merger gets apparent confirmation from Elon Musk
The comment follows reports that the rocket maker is weighing a transaction that could further consolidate Musk’s space and AI ventures.
Elon Musk appeared to confirm reports that SpaceX is exploring a potential merger with artificial intelligence startup xAI by responding positively to a post about the reported transaction on X.
Musk’s comment follows reports that the rocket maker is weighing a transaction that could further consolidate his space and AI ventures.
SpaceX xAI merger
As per a recent Reuters report, SpaceX has held discussions about merging with xAI, with the proposed structure potentially involving an exchange of xAI shares for SpaceX stock. The value, structure, and timing of any deal have not been finalized, and no agreement has been signed.
Musk appeared to acknowledge the report in a brief reply on X, responding “Yeah” to a post that described SpaceX as a future “Dyson Swarm company.” The comment references a Dyson Swarm, a sci-fi megastructure concept that consists of a massive network of satellites or structures that orbit a celestial body to harness its energy.
Reuters noted that two entities were formed in Nevada on January 21 to facilitate a potential transaction for the possible SpaceX-xAI merger. The discussions remain ongoing, and a transaction is not yet guaranteed, however.
AI and space infrastructure
A potential merger with xAI would align with Musk’s stated strategy of integrating artificial intelligence development with space-based systems. Musk has previously said that space-based infrastructure could support large-scale computing by leveraging continuous solar energy, an approach he has framed as economically scalable over time.
xAI already has operational ties to Musk’s other companies. The startup develops Grok, a large language model that holds a U.S. Department of Defense contract valued at up to $200 million. AI also plays a central role in SpaceX’s Starlink and Starshield satellite programs, which rely on automation and machine learning for network management and national security applications.
Musk has previously consolidated his businesses through share-based transactions, including Tesla’s acquisition of SolarCity in 2016 and xAI’s acquisition of X last year. Bloomberg has also claimed that Musk is considering a merger between SpaceX and Tesla in the future.
Tesla confirms that it finally solved its 4680 battery’s dry cathode process
Tesla Giga Texas to feature massive Optimus V4 production line
