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SpaceX to use superalloys in Mars rocket Raptor engines, says Elon Musk
A few days after he touched upon methods of creating BFR propellant on Mars, SpaceX CEO Elon Musk mentioned in a tweet that the launch company was using cutting-edge combinations of metals (known as superalloys) to ensure the efficiency and reliability of its Raptor rocket engine, a critical requirement for BFR to enable sustainable colonization of Mars.
In response to a tweeted question about types of metal alloys currently in use at SpaceX, Musk briefly delved into the complexities of building BFR’s propulsion system, particularly with respect to alloys capable of surviving the intense conditions inside a rocket engine:
“[SpaceX is using] SX 300 & soon SX 500. Kind of a modern version of Inconel superalloys. High strength at temperature, extreme oxidation resistance. Needed for ~800 atmosphere, hot, oxygen-rich turbopump on Raptor rocket engine.” – Elon Musk
There’s a lot to break down for the layperson in Musk’s tweet. First and foremost, commenters (your author included) immediately jumped to the conclusion that “SX 300/500” referred to some sort custom SpaceX material, given that SX is a frequent shorthand for SpaceX used in the enthusiast community. In reality, it was quickly discovered that the requirements Musk described for the material – namely “high strength at temperature [&] extreme oxidation resistance” – were nearly the exact same qualities of single-crystal superalloys, extremely advanced metal formulations also notated as SC or SX. It’s quite the apt coincidence that SpaceX will apparently rely on SX alloys for critical components of BFR propulsion.

A 2017 test-firing of the mature development Raptor, roughly 50% less powerful than the full-scale system. (SpaceX)
Single-crystal superalloys employ small amounts of exotic elements in order to better ensure truly unusual crystal formation in metal structures. In the case of SX alloys, the optimal result is a monolithic metal structure that effectively has no visible grain (think wood grain but in metal) – the resulting metal would be a huge monolithic crystal, in other words, uniform down to a near-atomic level. These SX superalloys are already used regularly for industrial applications requiring the ability to reliably operate in extremely corrosive high-pressure, high-temperature environments for long periods of time, most frequently seen in gas turbines for energy generation and airplane propulsion.
Per Musk, SpaceX intends to take those alloys a step further, developing its own SX-300 and SX-500 iterations for the purpose of building a reliable, robust turbopump for the Raptor propulsion system. In pursuit of the greatest possible efficiency, Raptor’s turbopump will run oxygen-rich, meaning that the inherently imperfect combustion process will lean towards excess oxygen in the exhaust, rather than excess methane. In simple terms, this choice is partially motivated by the fact that oxygen molecules are slightly lighter than methane molecules (15.999u vs. 16.04u). More importantly, the higher the pressure in the turbopump, the higher the pressure in Raptor’s combustion chamber, which directly correlates with more efficient combustion and thus a more efficient rocket engine overall. All improvements to its subcomponents will inherently end up benefiting SpaceX’s BFR booster and spaceship, the latter of which is already nearing initial prototype construction.
- SpaceX’s current Texas facilities feature a test stand for Raptor, the engine intended to power BFR and BFS to Mars. (SpaceX)
- SpaceX’s Raptor proceeds through the complex process of ignition. (SpaceX)
- SpaceX’s subscale Raptor engine has completed more than 1200 seconds of testing in less than two years. (SpaceX)
- SpaceX’s three-bay Raptor test stand as of April 17. The middle bay is currently home to the subscale Raptor test program. (Aero Photo)
While SpaceX cut its original Raptor specifications by roughly 50% compared to its 2016 goals, it appears that the company’s ambitions for the downsized Raptor are smaller in name only. In a May 2018 presentation, Chief of Propulsion Tom Mueller foreshadowed those future ambitions while humbly acknowledging that the Merlin 1D powering Falcon 9 and Heavy is already a masterpiece of engineering: “Merlin holds the thrust to weight record for now… but Raptor’s coming.”
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News
Tesla HW4.5 spotted in new Model Y, triggers speculation
Owners taking delivery of recent Model Y builds have identified components labeled “AP45.”
Tesla’s Hardware 4.5 computer appears to have surfaced in newly delivered Model Y vehicles, prompting fresh speculation about an interim upgrade ahead of the company’s upcoming AI5 chip.
Owners taking delivery of recent Model Y builds have identified components labeled “AP45,” suggesting Tesla may have quietly started rolling out revised autonomy hardware.
Hardware 4.5 appears in new Model Y units
The potential Hardware 4.5 sighting was first reported by Model Y owner @Eric5un, who shared details of a Fremont-built 2026 Model Y AWD Premium delivered this January. As per the Model Y owner, the vehicle includes a new front camera housing and a 16-inch center display, along with an Autopilot computer labeled “AP45” and part number 2261336-02-A.
The Tesla owner later explained that he confirmed the part number by briefly pulling down the upper carpet liner below the Model Y’s glovebox. Other owners soon reported similar findings. One Model Y Performance owner noted that their December build also appeared to include Hardware 4.5, while another owner of an Austin-built Model Y Performance reported spotting the same “AP45” hardware.
These sightings suggest that Tesla may already be installing revised FSD computers in its new Model Y batches, despite the company not yet making any formal announcements about Hardware 4.5.
What Hardware 4.5 could represent
Clues about Hardware 4.5 have surfaced previously in Tesla’s Electronic Parts Catalog. As reported by NotATeslaApp, the catalog has listed a component described as “CAR COMPUTER – LEFT HAND DRIVE – PROVISIONED – HARDWARE 4.5.” The component, which features the part number 2261336-S2-A, is priced at $2,300.00.
Longtime Tesla hacker @greentheonly has noted that Tesla software has contained references to a possible three-SoC architecture for some time. Previous generations of Tesla’s FSD computer, including Hardware 3 and Hardware 4, use a dual-SoC design for redundancy. A three-SoC layout could allow for higher inference throughput and improved fault tolerance.
Such an architecture could also serve as a bridge to AI5, Tesla’s next-generation autonomy chip expected to enter production later in 2026. As Tesla’s neural networks grow larger and more computationally demanding, Hardware 4.5 may provide additional headroom for vehicles built before AI5 becomes widely available.
Elon Musk
Elon Musk’s Grokipedia is getting cited by OpenAI’s ChatGPT
Some responses generated by OpenAI’s ChatGPT have recently referenced information from Grokipedia.
Some responses generated by OpenAI’s ChatGPT have recently referenced information from Grokipedia, an AI-generated encyclopedia developed by rival xAI, which was founded by Elon Musk. The citations appeared across a limited set of queries.
Reports about the matter were initially reported by The Guardian.
Grokipedia references in ChatGPT
Grokipedia launched in October as part of xAI’s effort to build an alternative to Wikipedia, which has become less centrist over the years. Unlike Wikipedia, which is moderated and edited by humans, Grokipedia is purely AI-powered, allowing it to approach topics with as little bias as possible, at least in theory. This model has also allowed Grokipedia to grow its article base quickly, with recent reports indicating that it has created over 6 million articles, more than 80% of English Wikipedia.
The Guardian reported that ChatGPT cited Grokipedia nine times across responses to more than a dozen user questions during its tests. As per the publication, the Grokipedia citations did not appear when ChatGPT was asked about high-profile or widely documented topics. Instead, Grokipedia was referenced in responses to more obscure historical or biographical claims. The pattern suggested selective use rather than broad reliance on the source, at least for now.
Broader Grokipedia use
The Guardian also noted that Grokipedia citations were not exclusive to ChatGPT. Anthropic’s AI assistant Claude reportedly showed similar references to Grokipedia in some responses, highlighting a broader issue around how large language models identify and weigh publicly available information.
In a statement to The Guardian, an OpenAI spokesperson stated that ChatGPT “aims to draw from a broad range of publicly available sources and viewpoints.” “We apply safety filters to reduce the risk of surfacing links associated with high-severity harms, and ChatGPT clearly shows which sources informed a response through citations,” the spokesperson stated.
Anthropic, for its part, did not respond to a request for comment on the matter. As for xAI, the artificial intelligence startup simply responded with a short comment that stated, “Legacy media lies.”
News
Tesla Europe builds momentum with expanding FSD demos and regional launches
Needless to say, it appears that Tesla is putting in some serious effort into boosting sales in Europe this year.
Tesla has been notably active across Europe in recent weeks, expanding its Full Self-Driving (Supervised) ride-along program, entering a new market, and showcasing its newest vehicles across multiple regions.
Needless to say, it appears that Tesla is putting in some serious effort into boosting sales in Europe this year.
Tesla Europe recently announced the expansion of its FSD (Supervised) ride-along experiences, inviting the public to experience the system on local roads. Initially available in Italy, France, and Germany when it launched, the program has now expanded to Hungary, Finland, and Spain.
The ride-along program allows participants to ride in the passenger seat and observe how FSD Supervised handles real-world traffic scenarios, including dense urban driving and other challenging conditions. Tesla has positioned the initiative as a way to familiarize European drivers and regulators with the system’s capabilities in everyday use. The program has received positive reviews so far, with many being impressed by FSD’s real-world capabilities.
Tesla also recently launched operations in Slovakia with a pop-up store and multi-day public event in Bratislava, as noted in an EV Wire report. The launch, held from January 16 to 18 at the Eurovea Mall Promenade, featured test drives, vehicle displays, including the Cybertruck, as well as family-focused attractions such as a mini-Tesla racetrack.
Local observers noted that Tesla Optimus was also shown at the event, while the Tesla Owners Slovakia club welcomed the brand with a coordinated light show near the Slovak National Theater. Tesla Europe later shared its appreciation for Slovakia in a post on its official social media account on X, stating, “Thanks, Slovakia, for the amazing last 3 days & for giving us such a warm welcome!”
Tesla’s Slovakia entry follows a familiar pattern used by the company in other European markets. Tesla opened a pop-up store in Bratislava as an initial step, with plans for a permanent showroom and a potential service center at a renovated site previously occupied by a Jeep and Dodge dealership. Tesla has used a similar approach in markets such as Czechia and Lithuania, where permanent facilities followed within a few months of pop-up launches.
Slovakia already has six Supercharging sites totaling 46 Superchargers, including two locations in Bratislava, providing early infrastructure support for Tesla owners. Tesla staff program manager Supratik Saha described the Slovakia launch as a strategic expansion in the heart of the EU, citing the country’s strong automotive manufacturing base and appetite for advanced technology.
Beyond the EU, the company also marked another milestone with the first Cybertruck deliveries in the United Arab Emirates, signaling continued geographic expansion for Tesla’s newest vehicle. Just like Tesla Slovakia, the Cybertruck also received a warm welcome from the UAE’s EV community.




