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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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Featured
Tesla Cybercab is coming to Asia this month as US service officially begins
Tesla Asia says Cybercab will be on display in Hong Kong, Tokyo, Beijing and Shanghai this month.
Tesla’s Cybercab is heading to Asia. The official Tesla Asia account posted on X Thursday, inviting Cybercab fans to “Come experience the future of autonomy in Hong Kong, Tokyo, Beijing & Shanghai.” The post went up within hours of Tesla’s own Cybercab milestone in Texas, where the company said Thursday it had begun offering rides in across Austin.
Exact dates and venues for the Asia tour haven’t been released yet, though Tesla Hong Kong replied to the announcement with “Cybercab will be on display in Hong Kong soon,” while Tesla Japan’s response pointed fans to a sign up page for updates. Neither post mentions test rides or a service area, and nothing so far suggests Tesla is launching Robotaxi operations in any of the four cities. Based on how Tesla has run past Cybercab tours, in Europe in late 2024 and at US shopping centers that same December, the Asia stops are almost certainly static displays at Tesla stores or public venues as a means to stimulate buzz for its future driverless ride-hailing service in the big cities.
Cybercab will be on display in Asia this month!
Come experience the future of autonomy in Hong Kong, Tokyo, Beijing & Shanghai. pic.twitter.com/wGmmEastfX— Tesla Asia (@Tesla_Asia) September 4, 2026
The timing lines up with Tesla’s only prior Cybercab appearance in the region, a booth at the China International Import Expo in Shanghai last November, which Teslarati covered at the time. At that event, Tesla’s regional general manager for Shanghai framed the car as evidence of the company’s broader mission, a message Tesla has since formalized in its Master Plan Part IV, which states that “autonomous vehicles have the capacity to dramatically improve the affordability, availability and safety of transportation while reducing pollution, particularly in our increasingly dense global cities.” The same document is where Tesla lays out its “sustainable abundance” framing for Cybercab and Optimus alike, describing the two as the hardware behind an AI driven push to cut the cost of transportation and labor at scale.
Whether Cybercab actually operates as a robotaxi anywhere in Asia remains an open question, considering China has already pushed an autonomous ride-hailing market that’s run on homegrown players like Baidu’s Apollo Go and Pony AI. For now, the four city tour reads as a marketing push timed to Austin’s momentum.
Lifestyle
Tesla Cybertruck targets job site crews with new Tailgate Utility Track and Bed Gear Box accessory
Tesla launched a $350 tailgate track and a $985 lockable Bed Gear Box for Cybertruck.
Tesla’s Cybertruck team added two more items to the Tesla Shop, targeting job site crews and owners who use the truck bed for actual work rather than just showing it off. The official Cybertruck X account posted the Tailgate Utility Track and the Bed Gear Box within minutes of each other, part of a five item batch that also included a reflective jacket, a spray paint hat and an updated reflective tee.
The Tailgate Utility Track runs $350 and turns the folded down tailgate into another mounting surface. It’s a single aluminum track with a T-slot for sliding accessories and two L-track attachment points, plus two load stops included in the box. The pitch is straightforward: strap down oversized cargo, like lumber or a cooler, that hangs off the back of the bed without it sliding out mid-drive. It bolts onto the existing tailgate and works on every Cybertruck trim.
Tailgate Utility Trackhttps://t.co/PCAYXlFBvS pic.twitter.com/sCV2NVxf1W
— Cybertruck (@cybertruck) September 3, 2026
The Bed Gear Box costs $985 and is a different kind of accessory. It’s a lockable aluminum storage box, 55.78 inches long, 19.8 inches wide and 7.79 inches tall, that mounts to the bed’s L-track rails and comes with two internal bins for smaller items. According to Tesla, at just over 57 pounds empty, it’s meant to stay in place rather than come in and out with each trip, giving owners a factory-fit alternative to loose totes for tools, recovery gear or emergency supplies. Tesla’s listing notes that Long Range and Dual Motor AWD Cybertrucks need the L-Tracks accessory installed separately before the Gear Box will mount, since L-tracks come standard only on certain configurations.
Tesla Cybertruck bed gear box accessory
Both accessories lean on the idea Tesla has been building toward since Elon Musk first described the Cybertruck’s third-party attachment strategy at the 2023 shareholder meeting, when he said the truck would ship with mounting points so outside companies, and Tesla itself, could keep adding gear without redesigning the bed. That’s the same L-track backbone underneath the tailgate shield and jumpseats Tesla launched last year, and the off-road armor package that arrived through the same X account in 2025.
Owners looking to round out the rest of the L-track ecosystem, cargo dividers, MOLLE panels, bed racks and similar gear, can find a wider range of options through our Cybertruck accessories collection.
Update: Tesla has announced Cybercab will enter the public fleet on Friday, September 4 at 5 p.m. CT. The article and headline have been updated to reflect this.
Tesla Cybercab rides will officially open to the public in Austin, Texas, on Friday, September 4 at 5 p.m. CT, as the company confirmed on Thursday following its launch event that the two-seater would be available in the company’s Robotaxi fleet.
Cybercab is Tesla’s first vehicle completely void of any manual controls. It has no steering wheel and no pedals, and it will utilize Tesla’s Full Self-Driving fleet to operate. The first rides have already happened, as those at the event were able to hail a Cybercab to any location within the company’s geofence in Austin.
Tesla’s $25K car is the Cybercab with no steering wheel or pedals
The addition of Cybercab to the public Robotaxi fleet is a major statement in Tesla’s trek to launch fully autonomous driving. For years, critics have complained about the need for drivers to continuously supervise the vehicle.
With Cybercab, there are no manual controls in the cockpit other than to control the seat, the center screen, and the climate. The vehicle is fully geared toward being a living room on wheels in a sense: equipped with Starlink V5 satellites, CEO Elon Musk said the vehicle would enable 4K live video, gaming, and other entertainment options during travel.
Cybercab is basically a super comfortable lounge on wheels with a great TV and epic sound https://t.co/X1aWKoJdJV
— Elon Musk (@elonmusk) September 3, 2026
Musk noted that Cybercab is “designed and built for maximally efficient autonomous operation.”
Tesla continues to push the envelope on autonomy, and over the next several months, the company could start selling Cybercab units to the public.
The company opened up a public interest form on its website to gauge demand, and many have already submitted requests to purchase a fleet of Cybercab units for their own personal ride-hailing side hustle.
The launch of Cybercab in this area marks a major accomplishment for Tesla, as it also announced that it has reached 1 million unsupervised autonomous miles since launching driverless rides on the Robotaxi fleet.
Things are moving along at a fine pace, and although we have waited for this for some time, the day has finally come when Tesla is offering self-driving rides of some kind to the public.
Tesla Cybercab is coming to Asia this month as US service officially begins
Tesla Cybertruck targets job site crews with new Tailgate Utility Track and Bed Gear Box accessory
