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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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Elon Musk
NASA updated Artemis III and SpaceX’s role just got more complicated
SpaceX’s Starship is the key to NASA’s Moon plan and the timeline is already slipping.
SpaceX has been at the center of NASA’s Moon ambitions for five years, and the updated Artemis III plan recently released by NASA makes that relationship more visible than ever. In April 2021, NASA awarded SpaceX a $2.89 billion contract to develop the Starship Human Landing System, selecting it as the sole provider to land astronauts on the Moon under Artemis III. Blue Origin filed legal protests, lost, and eventually received its own contract, but SpaceX was always the program’s primary lander contractor.
The original plan called for Starship to land two astronauts on the lunar south pole. That mission slipped as Starship development ran behind schedule, and in February 2026, NASA officially revised the Artemis III architecture entirely. The mission will now remain in low Earth orbit and serve as a crewed rendezvous and docking test between the Orion spacecraft and both the SpaceX Starship HLS pathfinder and Blue Origin’s Blue Moon Mark 2 pathfinder, with the actual Moon landing pushed to Artemis IV in 2028.
What makes SpaceX’s position particularly significant is the direct line between this week’s Starship V3 launch and the Artemis timeline. The Starship HLS is essentially a modified version of the V3 upper stage, meaning SpaceX cannot realistically prepare a lander for a 2027 docking test until it has demonstrated that the base vehicle flies reliably at scale. Flight 12, targeting this week, is the first data point in that sequence.
NASA has spent nearly $7 billion on Human Landing System development since awarding contracts to SpaceX and Blue Origin in 2021 and 2023, and NASA administrator Jared Isaacman has indicated a desire to drive down costs going forward. As Teslarati reported, before Starship HLS can put anyone on the Moon it has to solve a problem no rocket has demonstrated at scale, which is refueling in orbit, requiring approximately ten tanker launches worth of propellant loaded into a depot before the lander has enough fuel to reach the lunar surface.
The Artemis III mission described by NASA is essentially a stress test for every system that needs to work before any of that happens.
SpaceX has gone from a launch contractor to the single most critical hardware provider in America’s return-to-the-Moon program. With an IPO targeting a $1.75 trillion valuation and Elon Musk’s compensation tied directly to Mars colonization, the pressure on every Starship milestone between now and 2028 has never been higher.
Tesla is continuing to refine and improve its Robotaxi program from A to Z, and it is now going to make some sweeping changes to the smartphone app portion of the suite.
The company is aiming to make some sweeping changes with the release of Robotaxi app version 26.4.5, which was recently decompiled by Tesla App Updates on X. The update reveals significant new code, focused on remote operations, safety protocols, and seamless autonomous ride-hailing.
These improvements evidently signal Tesla’s preparations for scaling unsupervised Cybercab deployments, particularly the steering wheel-less variants spotted in production. The enhancements emphasize providing a reliable experience that gives passengers support when needed, along with operational efficiency.
Version 26.4.5 of the Robotaxi app has been de-compiled and we’ve got some interesting things added this update (https://t.co/jInbED7fOv):
– Remote Operator Voice Calls 📞
– Proactive Remote Assistance 🤖
– Manual Override + Remote Start for wheel-less Cybercabs 🎮
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— Tesla App Updates (iOS) (@Tesla_App_iOS) May 16, 2026
Remote Operator Voice Calls
One standout addition is support for remote operator voice calls. The app now includes a dedicated native voice-communication system linking passengers directly to Tesla teleoperators via the vehicle’s cabin microphone and speakers.
This feature allows real-time assistance during rides, addressing issues like navigation questions or comfort adjustments without disrupting the autonomous journey. It builds on existing support protocols, making human intervention more accessible and intuitive.
Proactive Remote Assistance
The update introduces proactive remote assistance capabilities. Rather than waiting for passenger-initiated requests, the system can anticipate and offer help based on monitored conditions.
This might include something like suggesting route changes, climate adjustments, or addressing potential delays. By integrating AI-driven monitoring with human oversight, Tesla aims to deliver a smoother, more attentive experience that exceeds traditional ride-sharing services.
Manual Override and Remote Start for Steering Wheel-less Cybercabs
A key highlight for the wheel-less Cybercab fleet is manual override plus remote start functionality. Fleet operators and technicians can now temporarily take control or remotely start vehicles lacking steering wheels. This is crucial for lower-speed maneuvers, such as getting vehicles from tight parking situations or even performing maintenance.
Controls are strictly limited for safety–typically to speeds under 2 MPH–ensuring these interventions remain emergency measures only.
Tesla is adding a secure “Enable Manual Drive” mode that will allow those fleet operators or others to take control temporarily.
Additionally, a Remote Start feature, which authorizes an empty vehicle to begin a driverless ride alone.
Ride-Hailing and Dispatch Features
Ride dispatch has been enhanced with soft-matching and multi-stop support. The app can intelligently pair riders with available Cybercabs while accommodating multiple destinations in a single trip.
This optimizes fleet utilization, reduces wait times, and improves efficiency for shared rides. Soft-matching likely considers factors like proximity, rider preferences, and vehicle availability for better user satisfaction.
Rider-Cabin Sync, Real-Time Routing
New synchronization tools allow the rider’s app to mirror and control cabin settings like seating, climate, and entertainment directly from their phone. Real-time routing updates adapt dynamically to traffic or road conditions, while dynamic safety monitoring continuously assesses the environment.
The app can now push updates directly to the main screen, enabling Center Display Control. Additionally, there is a dedicated navigation protocol sharing the exact coordinates of road closures and construction, which could prevent the car from getting stuck and needing manual override.
These features create a cohesive, responsive experience where the vehicle and app work in harmony.
Kill Switch
A high-security command lets Tesla completely freeze a vehicle’s ability to drive. This would take the vehicle out of the Robotaxi fleet for any reason Tesla sees fit, and would not allow it to be put into gear even with the correct equipment, like valid keys.
Elon Musk
SpaceX just forced Verizon, AT&T and T-Mobile to team up for the first time in history
AT&T, T-Mobile, and Verizon just joined forces for one reason: Starlink is winning.
America’s three largest wireless carriers, AT&T, T-Mobile, and Verizon, announced on On May 14, 2026 that they had agreed in principle to form a joint venture aimed at pooling their spectrum resources to expand satellite-based direct-to-device (D2D) connectivity across the United States in what can be seen as a direct response to SpaceX’s Starlink initiative. D2D, in plain terms, is technology that lets a standard smartphone connect directly to a satellite in orbit, the same way it connects to a cell tower, with no extra hardware required.
The alliance is widely seen as a means to slow Starlink’s rapid expansion in the satellite internet and mobile markets. SpaceX’s Starlink Mobile service launched commercially in July 2025 through a partnership with T-Mobile, starting with messaging before expanding to broadband data. SpaceX secured access to valuable wireless spectrum through its $17 billion deal with EchoStar, paving the way for significantly faster satellite-to-phone speeds.
SpaceX was not shy about its reaction. SpaceX president and COO Gwynne Shotwell responded on X: “Weeeelllll, I guess Starlink Mobile is doing something right! It’s David and Goliath (X3) all over again — I’m bettin’ on David.” SpaceX’s VP of Satellite Policy David Goldman went further, flagging potential antitrust concerns and asking whether the DOJ would even allow three dominant competitors to coordinate in a market where a new rival is actively entering.
Weeeelllll, I guess @Starlink Mobile is doing something right! It’s David and Goliath (X3) all over again — I’m bettin’ on David 🙂 https://t.co/5GzS752mxL
— Gwynne Shotwell (@Gwynne_Shotwell) May 14, 2026
Financial analysts at LightShed Partners were blunt, saying the announcement showed the three carriers are “nervous,” and pointed to the timing: “You announce an agreement in principle when the point is the announcement, not the deal. The timing, weeks ahead of the SpaceX roadshow, was the point.”
As Teslarati reported, SpaceX’s next generation Starlink V2 satellites will deliver up to 100 times the data density of the current system, with custom silicon and phased array antennas enabling around 20 times the throughput of the first generation. The carriers’ JV, which has no definitive agreement, no financial structure, and no deployment timeline yet, will need to move quickly to matter.
Elon Musk’s SpaceX is targeting a Nasdaq listing as early as June 12, aiming for what would be the largest IPO in history. With Starlink now serving over 9 million subscribers across 155 countries, holding 59 carrier partnerships globally, and now powering Air Force One, the carriers’ joint venture announcement landed at exactly the wrong time to look like anything other than a defensive move.
NASA updated Artemis III and SpaceX’s role just got more complicated
Tesla is making sweeping improvements to Robotaxi
