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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 Diner to transition to full-service restaurant as Chef heads for new venture
“I am leaving the Tesla Diner project to focus on the opening of Mish, my long-desired Jewish deli. Projects like Mish and the Tesla Diner require a sharpness of focus and attention, and my focus and attention is now squarely on Mish.”
Tesla Diner, the all-in-one Supercharging and dining experience located in Los Angeles, will transition to a full-service restaurant in January, staff said, as Chef Eric Greenspan said he would take on a new project.
A report from the Los Angeles Times says Greenspan confirmed through a text that he would leave the Diner and focus on the opening of his new Jewish deli, Mish.
Greenspan confirmed to the paper:
“I am leaving the Tesla Diner project to focus on the opening of Mish, my long-desired Jewish deli. Projects like Mish and the Tesla Diner require a sharpness of focus and attention, and my focus and attention is now squarely on Mish.”
Greenspan took on the job at the Tesla Diner and curated the menu back in March, focusing on locally-sourced ingredients and items that would play on various company products, like Cybertruck-shaped boxes that hold burgers.
Tesla Cybertruck leftovers are the main course at the Supercharger Diner
The Tesla Diner has operated as somewhat of a self-serve establishment, where Tesla owners can order directly from their vehicles through the center touchscreen. It was not exclusive to Tesla owners. Guests could also enter and order at a counter, and pick up their food, before sitting at a booth or table.
However, the report indicates Tesla is planning to push it toward a sit-down restaurant, full of waiters, waitresses, and servers, all of which will come to a table after you are seated, take your order, and serve your food.
It will be more of a full-featured restaurant experience moving forward, which is an interesting move from the company, but it also sounds as if it could be testing for an expansion.
We know that Tesla is already considering expanding locations, as it will be heading to new areas of the country. CEO Elon Musk has said that Tesla will be considering locations in Palo Alto near the company’s Engineering HQ, and in Austin, where its HQ and Gigafactory Texas are located.
Musk said that the Diner has been very successful in its first few months of operation.
News
Tesla adds new surprising fee to Robotaxi program
“Additional cleaning was required for the vehicle after your trip. A fee has been added to your final cost to cover this service. Please contact us if you have any questions.”
Tesla has added a new and somewhat surprising fee to the Robotaxi program. It’s only surprising because it was never there before.
Tesla shocked everyone when it launched its Robotaxi platform and offered riders the opportunity to tip, only to tell them they do not accept tips. It was one of the company’s attempts at being humorous as it rolled out its driverless platform to people in Austin.
As it has expanded to new cities and been opened to more people, as it was yesterday to iOS users, Tesla has had to tweak some of the minor details of the Robotaxi and ride-hailing platforms it operates.
First Look at Tesla’s Robotaxi App: features, design, and more
With more riders, more vehicles, and more operational jurisdictions, the company has to adjust as things become busier.
Now, it is adjusting the platform by adding “Cleaning Fees” to the Robotaxi platform, but it seems it is only charged if the vehicle requires some additional attention after your ride.
The app will communicate with the rider with the following message (via Not a Tesla App):
“Additional cleaning was required for the vehicle after your trip. A fee has been added to your final cost to cover this service. Please contact us if you have any questions.”
The cost of the cleaning will likely depend on how severe the mess is. If you spill a soda, it will likely cost less than if you lose your lunch in the back of the car because you had a few too many drinks.
This is an expected change, and it seems to be one that is needed, especially considering Tesla is operating a small-scale ride-hailing service at the current time. As it expands to more states and cities and eventually is available everywhere, there will be more situations that will arise.
The messes in vehicles are not a new situation, especially in a rideshare setting. It will be interesting to see if Tesla will enable other fees, like ones for riders who request a ride and do not show up for it.
News
Tesla Model Y sold out in China for 2025
Customers who wish to get their cars by the end of the year would likely need to get an inventory unit.
It appears that the Model Y has been sold out for 2025 in China. This seems to be true for the four variants of the vehicle that are currently offered in the country.
Tesla China’s order page update
A look at Tesla China’s order page for the Model Y shows a message informing customers that those who wish to guarantee delivery by the end of the year should purchase an inventory unit. This was despite the Model Y RWD and Model Y L showing an estimated delivery timeline of 4-8 weeks, and the Model Y Long Range RWD and Model Y Long Range AWD showing 4-13 weeks.
As per industry watchers, these updates on the Model Y’s order page suggest that Tesla China’s sales capacity for the remainder of 2025 has been sold out. The fact that estimated delivery timeframes for the Model Y Long Range RWD and AWD extend up to 13 weeks also bodes well for demand for the vehicle, especially given strong rivals like the Xiaomi YU7, which undercuts the Model Y in price.
Tesla China’s upcoming big updates
What is quite interesting is that Tesla China is still competing in the country with one hand partly tied behind its back. So far, Tesla has only been able to secure partial approval for its flagship self-driving software, FSD, in China. This has resulted in V14 not being rolled out to the country yet. Despite this, Tesla China’s “Autopilot automatic assisted driving on urban roads,” as the system is called locally, has earned positive reviews from users.
As per Elon Musk during the 2025 Annual Shareholder Meeting, however, Tesla is expecting to secure full approval for FSD in China in early 2026. “We have partial approval in China, and we hopefully will have full approval in China around February or March or so. That’s what they’ve told us,” Musk said.



