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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.
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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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Starlink achieves major milestones in 2025 progress report
Starlink wrapped up 2025 with impressive growth, adding more than 4.6 million new active customers and expanding service to 35 additional countries, territories, and markets.
Starlink wrapped up 2025 with impressive growth, adding more than 4.6 million new active customers and expanding service to 35 additional countries, territories, and markets. The company also completed deployment of its first-generation Direct to Cell constellation, launching over 650 satellites in just 18 months to enable cellular connectivity.
SpaceX highlighted Starlink’s impressive 2025 progress in an extensive report.
Key achievements from Starlink’s 2025 Progress
Starlink connected over 4.6 million new customers with high-speed internet while bringing service to 35 more regions worldwide in 2025. Starlink is now connecting 9.2 million people worldwide. The service achieved this just weeks after hitting its 8 million customer milestone.
Starlink is now available in 155 markets, including areas that are unreachable by traditional ISPs. As per SpaceX, Starlink has also provided over 21 million airline passengers and 20 million cruise passengers with reliable high-speed internet connectivity during their travels.
Starlink Direct to Cell
Starlink’s Direct to Cell constellation, more than 650 satellites strong, has already connected over 12 million people at least once, marking a breakthrough in global mobile coverage.
Starlink Direct to Cell is currently rolled out to 22 countries and 6 continents, with over 6 million monthly customers. Starlink Direct to Cell also has 27 MNO partners to date.
“This year, SpaceX completed deployment of the first generation of the Starlink Direct to Cell constellation, with more than 650 satellites launched to low-Earth orbit in just 18 months. Starlink Direct to Cell has connected more than 12 million people, and counting, at least once, providing life-saving connectivity when people need it most,” SpaceX wrote.
News
Giga Nevada celebrates production of 6 millionth drive unit
To celebrate the milestone, the Giga Nevada team gathered for a celebratory group photo.
Tesla’s Giga Nevada has reached an impressive milestone, producing its 6 millionth drive unit as 2925 came to a close.
To celebrate the milestone, the Giga Nevada team gathered for a celebratory group photo.
6 million drive units
The achievement was shared by the official Tesla Manufacturing account on social media platform X. “Congratulations to the Giga Nevada team for producing their 6 millionth Drive Unit!” Tesla wrote.
The photo showed numerous factory workers assembled on the production floor, proudly holding golden balloons that spelled out “6000000″ in front of drive unit assembly stations. Elon Musk gave credit to the Giga Nevada team, writing, “Congrats on 6M drive units!” in a post on X.
Giga Nevada’s essential role
Giga Nevada produces drive units, battery packs, and energy products. The facility has been a cornerstone of Tesla’s scaling since opening, and it was the crucial facility that ultimately enabled Tesla to ramp the Model 3 and Model Y. Even today, it serves as Tesla’s core hub for battery and drivetrain components for vehicles that are produced in the United States.
Giga Nevada is expected to support Tesla’s ambitious 2026 targets, including the launch of vehicles like the Tesla Semi and the Cybercab. Tesla will have a very busy 2026, and based on Giga Nevada’s activities so far, it appears that the facility will be equally busy as well.
News
Tesla Supercharger network delivers record 6.7 TWh in 2025
The network now exceeds 75,000 stalls globally, and it supports even non-Tesla vehicles across several key markets.
Tesla’s Supercharger Network had its biggest year ever in 2025, delivering a record 6.7 TWh of electricity to vehicles worldwide.
To celebrate its busy year, the official @TeslaCharging account shared an infographic showing the Supercharger Network’s growth from near-zero in 2012 to this year’s impressive milestone.
Record 6.7 TWh delivered in 2025
The bar chart shows steady Supercharger energy delivery increases since 2012. Based on the graphic, the Supercharger Network started small in the mid-2010s and accelerated sharply after 2019, when the Model 3 was going mainstream.
Each year from 2020 onward showed significantly more energy delivery, with 2025’s four quarters combining for the highest total yet at 6.7 TWh.
This energy powered millions of charging sessions across Tesla’s growing fleet of vehicles worldwide. The network now exceeds 75,000 stalls globally, and it supports even non-Tesla vehicles across several key markets. This makes the Supercharger Network loved not just by Tesla owners but EV drivers as a whole.
Resilience after Supercharger team changes
2025’s record energy delivery comes despite earlier 2024 layoffs on the Supercharger team, which sparked concerns about the system’s expansion pace. Max de Zegher, Tesla Director of Charging North America, also highlighted that “Outside China, Superchargers delivered more energy than all other fast chargers combined.”
Longtime Tesla owner and FSD tester Whole Mars Catalog noted the achievement as proof of continued momentum post-layoffs. At the time of the Supercharger team’s layoffs in 2024, numerous critics were claiming that Elon Musk was halting the network’s expansion altogether, and that the team only remained because the adults in the room convinced the juvenile CEO to relent.
Such a scenario, at least based on the graphic posted by the Tesla Charging team on X, seems highly implausible.
Starlink achieves major milestones in 2025 progress report
Giga Nevada celebrates production of 6 millionth drive unit
