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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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Tesla has officially launched the Model Y L in the United States and Puerto Rico for $61,990. It is the longer-wheelbase version of the Model Y, and has been available in China since last year.
Tesla brings the Model Y L to the U.S. just months after it phased out the only pure SUV in its lineup, the Model X. It is slightly longer than the Model Y configurations that are already available in the U.S., and features a three-row, six-seat setup with Captain’s Chairs being among the many features that make this a truly fantastic offering.
The Model Y L is priced competitively at $61,990, and features 325 miles of range and a 0-60 MPH in just 4.4 seconds.
Tesla also added a handful of new features that are not available in even the Premium Model Y. Here’s a full list of its features:
- Heated/Ventilated Front Seats with Powered Thigh Cushion
- Heated/Ventilated Captain’s Seats in Second Row with Powered Armrests & One-Touch Fold
- Heated Third-Row Seats with Power Recline, One-Touch Fold & Child Seat Anchors
- Improved Airflow, Increased Efficiency, More Range
- 89 cubic feet of trunk space
- Upgraded Acoustic Glass and Suspension to Minimize Road Noise
- Adaptive Damping for a Smooth, Stable Ride
- Staggered Tires for Enhanced Grip
- Larger Tailgate for Better Rear Visibility and Bigger Windows Overall
- 16″ First Row and 8″ Second Row Touchscreens
- 19-Speaker Immersive Tesla Audio
- 50W Wireless Charging Pads with Active Cooling and Charging Ports for All Other Seats
- FSD Supervised and Integrated Grok AI
Tesla is also delivering these first units as a “Launch Series,” which comes with additional features, such as:
- Door Trim Puddle Lights
- Suede Dashboard Wing
- Exterior and Interior Badging
- Floor Mats
- Sill Plates
The launch of the Model Y L in the U.S. marks a huge offering from Tesla to U.S. consumers. People have been calling for Tesla to bring a larger car to the U.S., and it needed it more than ever now that the Model X is gone.
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- Credit: Tesla
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- Credit: Tesla
It is a huge accomplishment for Tesla to get the Model Y L to the U.S., and after reporting strong deliveries today, it will be interesting to see how this car impacts future quarterly delivery reports.
Deliveries for the Model Y L “Launch Series” are slated for September or October of this year.
Tesla just told us twice that the Model Y L is coming to the U.S., and two social media posts definitely just tipped the company’s hand, as if they wanted it to be any other way.
The two social media posts basically confirm that the slightly longer version of the Model Y will be heading to the United States soon, and many have speculated that the company could launch the vehicle as soon as this weekend.
The first post was directly from Tesla, and it showed an incredibly long Dachshund, with words above that said, “Looking forward to the long weekend.”
Looking forward to the long weekend pic.twitter.com/URzH6zOUdn
— Tesla (@Tesla) July 1, 2026
Anyone who knows Tesla knows the company loves to troll its fans and have fun, and this is a perfect example of that. While not a direct acknowledgement, Tesla is very involved on social media, especially CEO Elon Musk’s platform X, and the company is well aware of what is being discussed within the community.
With recent sightings of Model Y L test mules in California, peeks of the vehicle at Giga Texas, and a large call for the car to come to the U.S., Tesla is simply stoking conversation with this.
However, the company also made another move that was recognized on social media. Tesla has a large gallery that includes photos of its products so media and others can use them. This gallery applies to the U.S. market specifically, unless otherwise specified.
Tesla uploaded a Model Y L to the Gallery last night:
This looks like a Model Y L https://t.co/TpnBwrLmH9
— TESLARATI (@Teslarati) July 2, 2026
This seems to be another indication that the Model Y L is coming to the United States.
Musk said last year that the Model Y L could make its way to the United States late this year, but it was not something that was set in stone by Tesla. The company definitely needs to establish something in the SUV market that is larger than the Model Y, and the Model Y L might be the answer.
Even still, there are consumers out there who would love Tesla to develop something even larger, like a competitor to the Tahoe or Expedition. Tesla has not really given much of an indication that it will go in that direction.
Tesla is using the vehicles’ internal microphones to improve build quality, Vice President of Engineering Lars Moravy revealed recently.
It’s no secret that Tesla is always finding ways to make its manufacturing operations more efficient, accurate, and valuable. Constantly trying to make its cars better, the company has never placed any restrictions on what it will do to improve everything from panel gaps to paint.
As Teslas have been driving autonomously on the property of the Gigafactory Texas plant for a while now, Moravy revealed to Herbert Ong in a new interview that cars rolling off production lines now autonomously navigate themselves through a bumps, squeaks, and rattles (BSR) portion of the line. This helps to identify any loose or improperly installed internal parts.
The cabin’s microphones, which are used for a variety of things in ownership, simultaneously monitor any noises inside the vehicle while it rolls through the BSR portion of the production line. Moravy actually revealed that Tesla is trying to build “Full Self-Hearing,” an AI system that will detect minor imperfections so they can be corrected before delivery.
It’s no secret that build quality is something that Tesla struggled with as it scaled to a fully massive production operation that manufactures over 1.6 million vehicles per year. However, in recent years, especially, there have not been as many complaints. Tesla has truly improved upon its build quality and paint quality over the past several years, especially in the U.S.
Tesla’s ‘megacasts’ are key to massive build quality improvements
While those improvements have been evident, there are still some complaints; no automaker is perfect with this. But this step will now ensure that every single car that rolls off the production lines at Gigafactory Texas will be void of any creaks, squeaks, or squeals when it leaves the factory.
This measure is one of the most unique we’ve seen in terms of a strategy to avoid build quality issues, but it is not exclusive to Tesla.
Ford uses acoustic analysis AI to find abnormalities in seat motors, climate control units, and other components. Suppliers and OEMs will also use microphone arrays or particle velocity sensors in end-of-line stations.
The full interview with Lars Moravy is available below:
🚨 If you’re a Tesla investor, this is one interview you don’t want to skip. The full video posted below.
Jeff Lutz @thejefflutz and I sat down with Tesla VP of Engineering Lars Moravy, and it was packed with insights!
A few of the biggest takeaways:
• Cybercab is expected to… pic.twitter.com/fhYSr2dCqP
— Herbert Ong (@herbertong) July 1, 2026
Tesla brings Model Y L ‘Launch Series’ to the U.S. at $61,990
Tesla just told us twice that Model Y L is coming to the U.S.
