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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 Energy has introduced the Powerwall Lease in conjunction with Tesla Electric, making the service available in Texas. This new option delivers whole-home backup power using two Powerwall units for a net monthly cost of $35 after credits, accompanied by a low fixed electricity rate.
Under the lease terms, customers pay a one-time order fee of $100. The base lease payment for the two Powerwalls is approximately $122 per month during the first year, subject to a 3 percent annual escalator thereafter. Enrollment in a qualifying Tesla Electric Backup plan or Virtual Power Plant plan provides an $87 monthly credit.
Powerwall Lease is now available with Tesla Electric in Texas
Whole-home backup for $35/month, with a low fixed electricity rate
– Two Powerwalls, $0 installation
– Storm Watch outage protection
– One app to manage it all pic.twitter.com/oTzqc6K3aF— Tesla Energy (@teslaenergy) August 13, 2026
This credit lowers the effective cost to roughly $35 per month plus applicable tax.
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Installation of the standard system carries no additional charge. The package features Storm Watch for outage protection and allows complete management through a single Tesla application. The system supplies continuous whole-home backup capability.
The Powerwall system enables households to maintain electricity during severe storms that disrupt the utility grid. When outages occur, the batteries automatically provide seamless backup power to the home.
Tesla announces 100k Powerwalls are participating in Virtual Power Plants
Tesla Storm Watch monitors weather forecasts and ensures the units are fully charged ahead of anticipated severe weather events so that power remains available throughout the disruption, keeping lights, refrigeration, and other essential systems operating without interruption.
Availability is restricted to select Texas locations where retail electric choice exists. Participants must lease exactly two Powerwall units and maintain continuous enrollment with Tesla Electric. Solar panels cannot be included under this particular lease arrangement.
The monthly credit activates automatically once the system is installed, receives permission to operate, and enrollment is confirmed. To retain the credit, customers are required to stay enrolled in Tesla Electric and fulfill all program conditions.
Nonstandard installations that involve electrical upgrades or special permitting may lead to extra expenses and might impact eligibility for the credit, so be sure to check with either your installer or Tesla to ensure you will still qualify.
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Elon Musk continues to tease the unveiling event for the Tesla Roadster, a continuing trend that has grown into a bigger game of “When” for fans who have been waiting years for the car to finally enter production.
A video shared on X of the Joe Rogan Experience podcast that Musk appeared on last year, teasing the Roadster unveiling, was shared once again on the social media platform. The poster said the Roadster event will be “unforgettable.”
Musk agreed:
Yes
— Elon Musk (@elonmusk) August 12, 2026
The timing is interesting because just yesterday, Musk said that we will be getting flying cars, and for years, Tesla has hinted that it could develop a SpaceX cold gas thruster package that would help the car float or fly for a short period of time.
It would be reasonable to assume Tesla’s major delays with this unveiling event are likely caused by the company’s need to break the rules and push the envelope on nearly everything. Last July, Lars Moravy, Tesla’s VP of Vehicle Engineering, said:
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“Roadster is definitely in development. We did talk about it last Sunday night. We are gearing up for a super cool demo. It’s going to be mind blowing. We showed Elon some cool demos last week of the tech we’ve been working on and he got a little excited.”
The latest updates that Tesla has given us are that the Roadster is in design development, and it did have several potential dates for an unveiling event this year, including April. It was then pushed to August.
However, there are no clues as to when Tesla will be ready, and fans are certainly getting frustrated with the delays.
For what it is worth, Franz von Holzhausen told Jay Leno this week that the event would be “very soon.”
We sure hope.
Lifestyle
Tesla’s driverless Cybercab just passed a big test with State Governor
Florida’s governor rode Tesla’s Cybercab at a closed test track and called the experience impressive.
Florida Governor Ron DeSantis rode in a Tesla Cybercab on a closed test track this week and came away impressed, posting on X that the vehicle “successfully navigated all hazards — a kid running into the street, a crash with police stopping traffic, a Model S cutting us off, etc.” He called the ride “impressive.”
The stop was part of a broader event Monday at SunTrax, a 775 acre state owned proving ground in Auburndale that Florida built specifically to test autonomous and connected vehicles before they reach public roads. Standing next to a gold Cybercab, DeSantis described the car in plain terms: “You go in there and you just sit. You have a screen. There’s no steering wheel, no pedals. Clearly these things could be very beneficial.”
We took a ride on a robotaxi on the Suntrax course and it successfully navigated all hazards — a kid running into the street, a crash with police stopping traffic, a Model S cutting us off, etc.
Impressive! https://t.co/FVAkzFLz3r
— Ron DeSantis (@RonDeSantis) August 11, 2026
DeSantis paired the praise with a caveat that has followed autonomous vehicles since the category existed. “You don’t want to be in an autonomous vehicle and it drives you into a ditch. That would not be good,” he said, framing safety validation as the gate before wider deployment.
SunTrax, the 2.25 mile oval which the state calls the only high speed autonomous vehicle test track in the Southeast, can simulate rain, pedestrian crossings, hills and crowded urban conditions at highway speeds, letting companies push a car past what an early public rollout would risk. Tesla, Waymo and Beep all use the facility, and Florida’s regulatory approach, among the most permissive for autonomous vehicles in the country, doesn’t require a human operator inside a fully autonomous car.
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Tesla has reason to want the blessing of Florida and states beyond, as the Cybercab entered volume production at Gigafactory Texas this spring and has since self certified as SAE Level 4 under Texas law. Public road testing so far has kept a safety monitor in the passenger seat, and Florida is where Tesla has been expanding its existing Model Y based Robotaxi service instead, adding Miami in July and then Orlando and Tampa two weeks later. A closed track endorsement from a sitting governor doesn’t change any of that, but it does put Tesla’s newest hardware in front of a state that has already shown it will move fast on rules.
Tesla launches Powerwall Lease for affordable home backup
Elon Musk teases Tesla Roadster unveiling once again
