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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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News
Anti-Tesla union leader ditches X, urges use of Threads instead
Tesla Sweden and IF Metall have been engaged in a bitter dispute for over two years now.
Marie Nilsson, chair of Sweden’s IF Metall union and a prominent critic of Tesla, has left X and is urging audiences to follow the union on Meta’s Threads instead.
Tesla Sweden and IF Metall have been engaged in a bitter dispute for over two years now.
Anti-Tesla union leader exits X
In a comment to Dagens Arbete (DA), Nilsson noted that her exit from X is not formally tied to IF Metall’s long-running labor dispute with Tesla Sweden. Still, she stated that her departure is affected by changes to the platform under Elon Musk’s leadership.
“We have stayed because many journalists pick up news there. But as more and more people have left X, we have felt that the standard has now been reached on that platform,” she said.
Jesper Pettersson, press officer at IF Metall, highlighted that the union’s departure from X is only indirectly linked to Tesla Sweden and Elon Musk. “Indirectly it does, since there is a lot of evidence that his ownership has caused the change in the platform to be so significant.
“We have nevertheless assessed that the platform had value for reaching journalists, politicians and other opinion leaders. But it is a microscopic proportion of the public and our members who are there, and now that value has decreased,” Petterson added.
IF Metall sees Threads as an X alternative
After leaving X, IF Metall has begun using Threads, Meta’s alternative to the social media platform. The union described the move as experimental, noting that it is still evaluating how effective the platform will be for outreach and visibility.
Pettersson acknowledged that Meta also does not operate under Sweden’s collective bargaining model, but said the union sees little alternative if it wants to remain visible online.
“In a perfect world, all large international companies would be supporters of the Swedish model when they come here. But unfortunately, the reality is not like that. If we are to be visible at all in this social media world, we have to play by the rules of the game. The alternative would be to become completely invisible, and that would not benefit our members,” he said.
Despite many recent rumors and various reports, Elon Musk confirmed today that SpaceX is not developing a phone based on Starlink, not once, but twice.
Today’s report from Reuters cited people familiar with the matter and stated internal discussions have seen SpaceX executives mulling the idea of building a mobile device that would connect directly to the Starlink satellite constellation.
Musk did state in late January that SpaceX developing a phone was “not out of the question at some point.” However, He also said it would have to be a major difference from current phones, and would be optimized “purely for running max performance/watt neural nets.”
Not out of the question at some point. It would be a very different device than current phones. Optimized purely for running max performance/watt neural nets.
— Elon Musk (@elonmusk) January 30, 2026
While Musk said it was not out of the question “at some point,” that does not mean it is currently a project SpaceX is working on. The CEO reaffirmed this point twice on X this afternoon.
Musk said, “Reuters lies relentlessly,” in one post. In the next, he explicitly stated, “We are not developing a phone.”
Reuters lies relentlessly
— Elon Musk (@elonmusk) February 5, 2026
We are not developing a phone
— Elon Musk (@elonmusk) February 5, 2026
Musk has basically always maintained that SpaceX has too many things going on, denying that a phone would be in the realm of upcoming projects. There are too many things in the works for Musk’s space exploration company, most notably the recent merger with xAI.
SpaceX officially acquires xAI, merging rockets with AI expertise
A Starlink phone would be an excellent idea, especially considering that SpaceX operates 9,500 satellites, serving over 9 million users worldwide. 650 of those satellites are dedicated to the company’s direct-to-device initiative, which provides cellular coverage on a global scale.
Nevertheless, there is the potential that the Starlink phone eventually become a project SpaceX works on. However, it is not currently in the scope of what the company needs to develop, so things are more focused on that as of right now.
Tesla has added a notable improvement to its Dashcam feature after complaints from owners have pushed the company to make a drastic change.
Perhaps one of the biggest frustrations that Tesla owners have communicated regarding the Dashcam feature is the lack of ability to retain any more than 60 minutes of driving footage before it is overwritten.
It does not matter what size USB jump drive is plugged into the vehicle. 60 minutes is all it will hold until new footage takes over the old. This can cause some issues, especially if you were saving an impressive clip of Full Self-Driving or an incident on the road, which could be lost if new footage was recorded.
This has now been changed, as Tesla has shown in the Release Notes for an upcoming Software Update in China. It will likely expand to the U.S. market in the coming weeks, and was first noticed by NotaTeslaApp.
The release notes state:
“Dashcam Dynamic Recording Duration – The dashcam dynamically adjusts the recording duration based on the available storage capacity of the connected USB drive. For example, with a 128 GB USB drive, the maximum recording duration is approximately 3 hours; with a 1 TB or larger USB drive, it can reach up to 24 hours. This ensures that as much video as possible is retained for review before it gets overwritten.”
Tesla Adds Dynamic Recording
Instead of having a 60-minute cap, the new system will now go off the memory in the USB drive. This means with:
- 128 GB Jump Drive – Up to Three Hours of Rolling Footage
- 1TB Jump Drive – Up to 24 Hours of Rolling Footage
This is dependent on the amount of storage available on the jump drive, meaning that if there are other things saved on it, it will take away from the amount of footage that can be retained.
While the feature is just now making its way to employees in China, it will likely be at least several weeks before it makes its way to the U.S., but owners should definitely expect it in the coming months.
It will be a welcome feature, especially as there will now be more customization to the number of clips and their duration that can be stored.
Anti-Tesla union leader ditches X, urges use of Threads instead
Elon Musk confirms SpaceX is not developing a phone
