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SpaceX begins installing new ‘Raptor 2’ engines on Super Heavy booster
SpaceX has begun installing new ‘Raptor 2’ engines on Super Heavy Booster 7 after the prototype completed a range of tests and returned to the company’s South Texas ‘Starbase’ rocket factory.
Earlier this month, SpaceX transported Booster 7 (B7) in the opposite direction, returning the 67-meter (~220 ft) tall rocket to Starbase’s orbital launch site (OLS) for the second time after it was forced to head back to the factory for repairs. Repairs completed, SpaceX dove headfirst into the process of verifying that the booster had been returned to full health and immediately filled its tanks to the brim with at least 3000 tons (>6.5M lb) of liquid nitrogen and oxygen – better known as a cryogenic proof test.
Less than 48 hours after completing its first post-repair test, Booster 7 sailed through another full cryoproof test without losing a beat. On May 13th, two days later, SpaceX attached a crane to Super Heavy B7 and removed it from the orbital launch mount before rolling the rocket back to Starbase’s build site on May 14th. Without official confirmation, which is increasingly rare, it was impossible to determine the results of the testing with certainty, but the speed of the process and Booster 7’s rapid launch mount removal made the two most extreme outcomes the most likely.
A quick return to the build site could have been explained by a significant vehicle failure or a major issue with SpaceX’s repair job – no point in continuing to test a vehicle that can’t be fully tested. On the exact opposite hand, a near-perfect test campaign in which all objectives were more or less achieved without major hiccups could also explain the quick return. In general, the evidence was in favor of the more optimistic explanation. Had a major issue been uncovered during the first post-repair cryoproof, it’s difficult to imagine that SpaceX would have completed the exact same test – in full less than 48 hours later.
However, SpaceX moved an in-situ Raptor engine installation stand towards Booster 7 and the orbital launch mount shortly before testing restarted, hinting – for the moment – that the company wanted to begin installing Raptor engines immediately after cryoproof testing. But mid-way through testing, the stand was moved back to its storage area and Super Heavy was instead removed from the mount and returned to the factory, adding a little uncertainty.
Concerns were immediately assuaged on May 17th when SpaceX was spotted moving Raptor engines from a production tent to the ‘megabay’ assembly building containing Booster 7. While the location of the new bay makes it difficult to peek inside from public viewpoints, preventing direct confirmation, it’s very likely SpaceX has begun installing new Raptor 2 engines on Super Heavy B7.
Additionally, confirming some of the more optimistic speculation about SpaceX’s decision to move Booster 7 back to build site, two of the three Raptor engines spotted on May 17th were also labeled “E26” and “E28.” Unless SpaceX’s engine numbering conventions have changed, the labels identify the engines as three of 20 ‘Raptor Boost’ engines that will ultimately populate the outer ring of Super Heavy B7’s aft end. More importantly, the installation of any Raptor Boost 2 (RB2) engines likely indicates that SpaceX has decided to install a full set of 33 Raptors on the booster before kicking off static fire testing.
To limit risk, SpaceX could have begun test-firing Booster 7 with just 1-3 Raptor engines installed and gradually added more as confidence grew. Instead, SpaceX appears to have accepted the added risk of losing 33 brand-new Raptor 2 engines in one fell swoop in return for the possibility of a much faster test campaign. If there are no major surprises during static fire testing, in other words, Booster 7 could be ready for flight far more quickly if the process begins with all 33 engines already installed. Installing Booster 7’s Raptors, heat shield, and aerocovers will be easier back at the build site.
Doing it all at once should also help prevent Booster 7 from suffering Booster 4’s fate and wallowing, unfinished, for months without completing a single useful test. If the gamble works, the first stage of a two-stage Starship could be ready for an orbital launch attempt in just a few months. If the gamble fails and Booster 7 is damaged, destroyed, or otherwise unable to pass the necessary tests, SpaceX will simply move on to Booster 8 sooner than later, having wasted less time on a more cautious Booster 7 test campaign.
It’s unclear how long it will take SpaceX to install all 33 Raptors, construct a heat shield around those engines, and finish buttoning up the rest of Booster 7. In an adjacent assembly bay, SpaceX appears to have nearly finished assembling a similarly upgraded Starship – Ship 24 – that’s first in line to ride Booster 7 into space. The company has also tentatively requested road closures for three 12-hour test windows on May 23rd, 24th, and 25th that either vehicle could use.
Elon Musk
Tesla confirms that work on Dojo 3 has officially resumed
“Now that the AI5 chip design is in good shape, Tesla will restart work on Dojo 3,” Elon Musk wrote in a post on X.
Tesla has restarted work on its Dojo 3 initiative, its in-house AI training supercomputer, now that its AI5 chip design has reached a stable stage.
Tesla CEO Elon Musk confirmed the update in a recent post on X.
Tesla’s Dojo 3 initiative restarted
In a post on X, Musk said that with the AI5 chip design now “in good shape,” Tesla will resume work on Dojo 3. He added that Tesla is hiring engineers interested in working on what he expects will become the highest-volume AI chips in the world.
“Now that the AI5 chip design is in good shape, Tesla will restart work on Dojo3. If you’re interested in working on what will be the highest volume chips in the world, send a note to AI_Chips@Tesla.com with 3 bullet points on the toughest technical problems you’ve solved,” Musk wrote in his post on X.
Musk’s comment followed a series of recent posts outlining Tesla’s broader AI chip roadmap. In another update, he stated that Tesla’s AI4 chip alone would achieve self-driving safety levels well above human drivers, AI5 would make vehicles “almost perfect” while significantly enhancing Optimus, and AI6 would be focused on Optimus and data center applications.
Musk then highlighted that AI7/Dojo 3 will be designed to support space-based AI compute.
Tesla’s AI roadmap
Musk’s latest comments helped resolve some confusion that emerged last year about Project Dojo’s future. At the time, Musk stated on X that Tesla was stepping back from Dojo because it did not make sense to split resources across multiple AI chip architectures.
He suggested that clustering large numbers of Tesla AI5 and AI6 chips for training could effectively serve the same purpose as a dedicated Dojo successor. “In a supercomputer cluster, it would make sense to put many AI5/AI6 chips on a board, whether for inference or training, simply to reduce network cabling complexity & cost by a few orders of magnitude,” Musk wrote at the time.
Musk later reinforced that idea by responding positively to an X post stating that Tesla’s AI6 chip would effectively be the new Dojo. Considering his recent updates on X, however, it appears that Tesla will be using AI7, not AI6, as its dedicated Dojo successor. The CEO did state that Tesla’s AI7, AI8, and AI9 chips will be developed in short, nine-month cycles, so Dojo’s deployment might actually be sooner than expected.
Elon Musk
Elon Musk’s xAI brings 1GW Colossus 2 AI training cluster online
Elon Musk shared his update in a recent post on social media platform X.
xAI has brought its Colossus 2 supercomputer online, making it the first gigawatt-scale AI training cluster in the world, and it’s about to get even bigger in a few months.
Elon Musk shared his update in a recent post on social media platform X.
Colossus 2 goes live
The Colossus 2 supercomputer, together with its predecessor, Colossus 1, are used by xAI to primarily train and refine the company’s Grok large language model. In a post on X, Musk stated that Colossus 2 is already operational, making it the first gigawatt training cluster in the world.
But what’s even more remarkable is that it would be upgraded to 1.5 GW of power in April. Even in its current iteration, however, the Colossus 2 supercomputer already exceeds the peak demand of San Francisco.
Commentary from users of the social media platform highlighted the speed of execution behind the project. Colossus 1 went from site preparation to full operation in 122 days, while Colossus 2 went live by crossing the 1-GW barrier and is targeting a total capacity of roughly 2 GW. This far exceeds the speed of xAI’s primary rivals.
Funding fuels rapid expansion
xAI’s Colossus 2 launch follows xAI’s recently closed, upsized $20 billion Series E funding round, which exceeded its initial $15 billion target. The company said the capital will be used to accelerate infrastructure scaling and AI product development.
The round attracted a broad group of investors, including Valor Equity Partners, Stepstone Group, Fidelity Management & Research Company, Qatar Investment Authority, MGX, and Baron Capital Group. Strategic partners NVIDIA and Cisco also continued their support, helping xAI build what it describes as the world’s largest GPU clusters.
xAI said the funding will accelerate its infrastructure buildout, enable rapid deployment of AI products to billions of users, and support research tied to its mission of understanding the universe. The company noted that its Colossus 1 and 2 systems now represent more than one million H100 GPU equivalents, alongside recent releases including the Grok 4 series, Grok Voice, and Grok Imagine. Training is also already underway for its next flagship model, Grok 5.
Elon Musk
Tesla AI5 chip nears completion, Elon Musk teases 9-month development cadence
The Tesla CEO shared his recent insights in a post on social media platform X.
Tesla’s next-generation AI5 chip is nearly complete, and work on its successor is already underway, as per a recent update from Elon Musk.
The Tesla CEO shared his recent insights in a post on social media platform X.
Musk details AI chip roadmap
In his post, Elon Musk stated that Tesla’s AI5 chip design is “almost done,” while AI6 has already entered early development. Musk added that Tesla plans to continue iterating rapidly, with AI7, AI8, AI9, and future generations targeting a nine-month design cycle.
He also noted that Tesla’s in-house chips could become the highest-volume AI processors in the world. Musk framed his update as a recruiting message, encouraging engineers to join Tesla’s AI and chip development teams.
Tesla community member Herbert Ong highlighted the strategic importance of the timeline, noting that faster chip cycles enable quicker learning, faster iteration, and a compounding advantage in AI and autonomy that becomes increasingly difficult for competitors to close.
AI5 manufacturing takes shape
Musk’s comments align with earlier reporting on AI5’s production plans. In December, it was reported that Samsung is preparing to manufacture Tesla’s AI5 chip, accelerating hiring for experienced engineers to support U.S. production and address complex foundry challenges.
Samsung is one of two suppliers selected for AI5, alongside TSMC. The companies are expected to produce different versions of the AI5 chip, with TSMC reportedly using a 3nm process and Samsung using a 2nm process.
Musk has previously stated that while different foundries translate chip designs into physical silicon in different ways, the goal is for both versions of the Tesla AI5 chip to operate identically. AI5 will succeed Tesla’s current AI4 hardware, formerly known as Hardware 4, and is expected to support the company’s Full Self-Driving system as well as other AI-driven efforts, including Optimus.
Tesla confirms that work on Dojo 3 has officially resumed
Elon Musk’s xAI brings 1GW Colossus 2 AI training cluster online
