News
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.
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- SpaceX’s current Texas facilities feature a test stand for Raptor, the engine intended to power BFR and BFS to Mars. (SpaceX)
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- SpaceX’s Raptor proceeds through the complex process of ignition. (SpaceX)
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- SpaceX’s subscale Raptor engine has completed more than 1200 seconds of testing in less than two years. (SpaceX)
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- 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 sees sharp November rebound in China as Model Y demand surges
New data from the China Passenger Car Association (CPCA) shows a 9.95% year-on-year increase and a 40.98% jump month-over-month.
Tesla’s sales momentum in China strengthened in November, with wholesale volumes rising to 86,700 units, reversing a slowdown seen in October.
New data from the China Passenger Car Association (CPCA) shows a 9.95% year-on-year increase and a 40.98% jump month-over-month. This was partly driven by tightened delivery windows, targeted marketing, and buyers moving to secure vehicles before changes to national purchase tax incentives take effect.
Tesla’s November rebound coincided with a noticeable spike in Model Y interest across China. Delivery wait times extended multiple times over the month, jumping from an initial 2–5 weeks to estimated handovers in January and February 2026 for most five-seat variants. Only the six-seat Model Y L kept its 4–8 week estimated delivery timeframe.
The company amplified these delivery updates across its Chinese social media channels, urging buyers to lock in orders early to secure 2025 delivery slots and preserve eligibility for current purchase tax incentives, as noted in a CNEV Post report. Tesla also highlighted that new inventory-built Model Y units were available for customers seeking guaranteed handovers before December 31.
This combination of urgency marketing and genuine supply-demand pressure seemed to have helped boost November’s volumes, stabilizing what had been a year marked by several months of year-over-year declines.
-->For the January–November period, Tesla China recorded 754,561 wholesale units, an 8.30% decline compared to the same period last year. The company’s Shanghai Gigafactory continues to operate as both a domestic production base and a major global export hub, building the Model 3 and Model Y for markets across Asia, Europe, and the Middle East, among other territories.
Tesla bear Michael Burry got blunt with his beliefs over the company’s valuation, which he called “ridiculously overvalued” in a newsletter to subscribers this past weekend.
“Tesla’s market capitalization is ridiculously overvalued today and has been for a good long time,” Burry, who was the inspiration for the movie The Big Short, and was portrayed by Christian Bale.
Burry went on to say, “As an aside, the Elon cult was all-in on electric cars until competition showed up, then all-in on autonomous driving until competition showed up, and now is all-in on robots — until competition shows up.”
Tesla bear Michael Burry ditches bet against $TSLA, says ‘media inflated’ the situation
For a long time, Burry has been skeptical of Tesla, its stock, and its CEO, Elon Musk, even placing a $530 million bet against shares several years ago. Eventually, Burry’s short position extended to other supporters of the company, including ARK Invest.
Tesla has long drawn skepticism from investors and more traditional analysts, who believe its valuation is overblown. However, the company is not traded as a traditional stock, something that other Wall Street firms have recognized.
While many believe the company has some serious pull as an automaker, an identity that helped it reach the valuation it has, Tesla has more than transformed into a robotics, AI, and self-driving play, pulling itself into the realm of some of the most recognizable stocks in tech.
Burry’s Scion Asset Management has put its money where its mouth is against Tesla stock on several occasions, but the firm has not yielded positive results, as shares have increased in value since 2020 by over 115 percent. The firm closed in May.
In 2020, it launched its short position, but by October 2021, it had ditched that position.
Tesla has had a tumultuous year on Wall Street, dipping significantly to around the $220 mark at one point. However, it rebounded significantly in September, climbing back up to the $400 region, as it currently trades at around $430.
It closed at $430.14 on Monday.
Tesla appears to be making a change to its exterior side repeater cameras, which are used for the company’s Full Self-Driving suite, and other features, like Sentry Mode.
The change appears to be a potential upgrade in preparation for the AI5 suite, which CEO Elon Musk said will be present on a handful of vehicles next year, but will not be widely implemented until 2027.
Currently, Tesla uses a Sony sensor lens with the model number IMX963, a 5-megapixel camera with better dynamic range and low-light performance over the past iteration in Hardware 3 vehicles. Cameras in HW3 cars were only 1.2 megapixels.
However, Tesla is looking to upgrade, it appears, as Tesla hacker greentheonly has spotted a new sensor model in its firmware code, with the model number IMX00N being explicitly mentioned:
Looks like Tesla is changing (upgrading?) cameras in (some?) new cars produced.
Where as HW4 to date used exterior cameras with IMX963, now they (might potentially) have something called IMX00N— green (@greentheonly) December 1, 2025
Sony has not announced any formal specifications for the IMX00N model, and although IMX963 has been used in AI4/HW4 vehicles, it only makes sense that Tesla would prepare to upgrade these external cameras once again in preparation for what it believes to be the second hardware iteration capable of fully autonomous self-driving.
Tesla has maintained that AI4/HW4 vehicles are capable of self-driving operation, but AI5 will likely help the company make significant strides, especially in terms of overall performance and data collection.
Tesla last updated its exterior cameras on its vehicles back in early 2023, as it transitioned to the 5-megapixel IMX963. It also added additional cameras to its vehicles in January with the new Model Y, which featured an additional lens on the front bumper to help with Full Self-Driving.
Tesla’s new self-driving computer (HW4): more cameras, radar, and more
Tesla sees sharp November rebound in China as Model Y demand surges
Tesla bear gets blunt with beliefs over company valuation
