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.
- 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.”
Follow us for live updates, peeks behind the scenes, and photos from Teslarati’s East and West Coast photographers.
Teslarati – Instagram – Twitter
Tom Cross – Twitter
Pauline Acalin – Twitter
Eric Ralph – Twitter
News
Tesla owners propose interesting theory about Apple CarPlay and EV tax credit
“100%. It’s needed for sales because for many prospective buyers, CarPlay is a nonnegotiable must-have. If they knew how good the Tesla UI is, they wouldn’t think they need CarPlay,” one owner said.
Tesla is reportedly bracing for the integration of Apple’s well-known iOS automotive platform, CarPlay, into its vehicles after the company had avoided it for years.
However, now that it’s here, owners are more than clear that they do not want it, and they have their theories about why it’s on its way. Some believe it might have to do with the EV tax credit, or rather, the loss of it.
Owners are more interested in why Tesla is doing this now, especially considering that so many have been outspoken about the fact that they would not use it in favor of the company’s user interface (UI), which is extremely well done.
After Bloomberg reported that Tesla was working on Apple CarPlay integration, the reactions immediately started pouring in. From my perspective, having used both Apple CarPlay in two previous vehicles and going to Tesla’s in-house UI in my Model Y, both platforms definitely have their advantages.
However, Tesla’s UI just works with its vehicles, as it is intuitive and well-engineered for its cars specifically. Apple CarPlay was always good, but it was buggy at times, which could be attributed to the vehicle and not the software, and not as user-friendly, but that is subjective.
Nevertheless, upon the release of Bloomberg’s report, people immediately challenged the need for it:
Everyone thinks they need it. I would think that too if I didn’t know how good Tesla’s interface was. CarPlay is a crappy layer on top of crappy info-navs, and people think it’s an imperative because it provides a level of consistency from car to car. They have no clue how much…
— Rich Stafford (@r26174_rich) November 14, 2025
How can it not be when the best engineers choose Tesla over Apple and Tesla’s core focus is auto vs Apple being mobile. It’s what Tesla does every day. It’s a side project for Apple. Still Apple is much better than any other auto OEM who attract lesser talent and make digital…
— Emu (@confessedemu) November 14, 2025
Some fans proposed an interesting point: What if Tesla is using CarPlay as a counter to losing the $7,500 EV tax credit? Perhaps it is an interesting way to attract customers who have not owned a Tesla before but are more interested in having a vehicle equipped with CarPlay?
“100%. It’s needed for sales because for many prospective buyers, CarPlay is a nonnegotiable must-have. If they knew how good the Tesla UI is, they wouldn’t think they need CarPlay,” one owner said.
Tesla has made a handful of moves to attract people to its cars after losing the tax credit. This could be a small but potentially mighty strategy that will pull some carbuyers to Tesla, especially now that the Apple CarPlay box is checked.
@teslarati :rotating_light: This is why you need to use off-peak rates at Tesla Superchargers! #tesla #evcharging #fyp ♬ Blue Moon – Muspace Lofi
Investor's Corner
Ron Baron states Tesla and SpaceX are lifetime investments
Baron, one of Tesla’s longest-standing bulls, reiterated that his personal stake in the company remains fully intact even as volatility pressures the broader market.
Billionaire investor Ron Baron says he isn’t touching a single share of his personal Tesla holdings despite the recent selloff in the tech sector. Baron, one of Tesla’s longest-standing bulls, reiterated that his personal stake in the company remains fully intact even as volatility pressures the broader market.
Baron doubles down on Tesla
Speaking on CNBC’s Squawk Box, Baron stated that he is largely unfazed by the market downturn, describing his approach during the selloff as simply “looking” for opportunities. He emphasized that Tesla remains the centerpiece of his long-term strategy, recalling that although Baron Funds once sold 30% of its Tesla position due to client pressure, he personally refused to trim any of his personal holdings.
“We sold 30% for clients. I did not sell personally a single share,” he said. Baron’s exposure highlighted this stance, stating that roughly 40% of his personal net worth is invested in Tesla alone. The legendary investor stated that he has already made about $8 billion from Tesla from an investment of $400 million when he started, and believes that figure could rise fivefold over the next decade as the company scales its technology, manufacturing, and autonomy roadmap.
A lifelong investment
Baron’s commitment extends beyond Tesla. He stated that he also holds about 25% of his personal wealth in SpaceX and another 35% in Baron mutual funds, creating a highly concentrated portfolio built around Elon Musk–led companies. During the interview, Baron revisited a decades-old promise he made to his fund’s board when he sought approval to invest in publicly traded companies.
“I told the board, ‘If you let me invest a certain amount of money, then I will promise that I won’t sell any of my stock. I will be the last person out of the stock,’” he said. “I will not sell a single share of my shares until my clients sold 100% of their shares. … And I don’t expect to sell in my lifetime Tesla or SpaceX.”
Watch Ron Baron’s CNBC interview below.
@teslarati :rotating_light: This is why you need to use off-peak rates at Tesla Superchargers! #tesla #evcharging #fyp ♬ Blue Moon – Muspace Lofi
News
Tesla CEO Elon Musk responds to Waymo’s 2,500-fleet milestone
While Tesla’s Robotaxi network is not yet on Waymo’s scale, Elon Musk has announced a number of aggressive targets for the service.
Elon Musk reacted sharply to Waymo’s latest milestone after the autonomous driving company revealed its fleet had grown to 2,500 robotaxis across five major U.S. regions.
As per Musk, the milestone is notable, but the numbers could still be improved.
“Rookie numbers”
Waymo disclosed that its current robotaxi fleet includes 1,000 vehicles in the San Francisco Bay Area, 700 in Los Angeles, 500 in Phoenix, 200 in Austin, and 100 in Atlanta, bringing the total to 2,500 units.
When industry watcher Sawyer Merritt shared the numbers on X, Musk replied with a two-word jab: “Rookie numbers,” he wrote in a post on X, highlighting Tesla’s intention to challenge and overtake Waymo’s scale with its own Robotaxi fleet.
While Tesla’s Robotaxi network is not yet on Waymo’s scale, Elon Musk has announced a number of aggressive targets for the service. During the third quarter earnings call, he confirmed that the company expects to remove safety drivers from large parts of Austin by year-end, marking the biggest operational step forward for Tesla’s autonomous program to date.
Tesla targets major Robotaxi expansions
Tesla’s Robotaxi pilot remains in its early phases, but Musk recently revealed that major deployments are coming soon. During his appearance on the All-In podcast, Musk said Tesla is pushing to scale its autonomous fleet to 1,000 cars in the Bay Area and 500 cars in Austin by the end of the year.
“We’re scaling up the number of cars to, what happens if you have a thousand cars? Probably we’ll have a thousand cars or more in the Bay Area by the end of this year, probably 500 or more in the greater Austin area,” Musk said.
With just two months left in Q4 2025, Tesla’s autonomous driving teams will face a compressed timeline to hit those targets. Musk, however, has maintained that Robotaxi growth is central to Tesla’s valuation and long-term competitiveness.
@teslarati :rotating_light: This is why you need to use off-peak rates at Tesla Superchargers! #tesla #evcharging #fyp ♬ Blue Moon – Muspace Lofi
-
News1 week agoTesla shares rare peek at Semi factory’s interior
-
Elon Musk1 week agoTesla says texting and driving capability is coming ‘in a month or two’
-
News7 days agoTesla makes online ordering even easier
-
News1 week agoTesla Model Y Performance set for new market entrance in Q1
-
News1 week agoTesla Cybercab production starts Q2 2026, Elon Musk confirms
-
News6 days agoTesla is launching a crazy new Rental program with cheap daily rates
-
News1 week agoTesla China expecting full FSD approval in Q1 2026: Elon Musk
-
News1 week agoTesla Model Y Performance is rapidly moving toward customer deliveries



