News
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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News
Tesla takes a step towards removal of Robotaxi service’s safety drivers
Tesla watchers are speculating that the implementation of in-camera data sharing could be a step towards the removal of the Robotaxi service’s safety drivers.
Tesla appears to be preparing for the eventual removal of its Robotaxi service’s safety drivers.
This was hinted at in a recent de-compile of the Robotaxi App’s version 25.11.5, which was shared on social media platform X.
In-cabin analytics
As per Tesla software tracker @Tesla_App_iOS, the latest update to the Robotaxi app featured several improvements. These include Live Screen Sharing, as well as a feature that would allow Tesla to access video and audio inside the vehicle.
According to the software tracker, a new prompt has been added to the Robotaxi App that requests user consent for enhanced in-cabin data sharing, which comprise Cabin Camera Analytics and Sound Detection Analytics. Once accepted, Tesla would be able to retrieve video and audio data from the Robotaxi’s cabin.
Video and audio sharing
A screenshot posted by the software tracker on X showed that Cabin Camera Analytics is used to improve the intelligence of features like request support. Tesla has not explained exactly how the feature will be implemented, though this might mean that the in-cabin camera may be used to view and analyze the status of passengers when remote agents are contacted.
Sound Detection Analytics is expected to be used to improve the intelligence of features like siren recognition. This suggests that Robotaxis will always be actively listening for emergency vehicle sirens to improve how the system responds to them. Tesla, however, also maintained that data collected by Robotaxis will be anonymous. In-cabin data will not be linked to users unless they are needed for a safety event or a support request.
Tesla watchers are speculating that the implementation of in-camera data sharing could be a step towards the removal of the Robotaxi service’s safety drivers. With Tesla able to access video and audio feeds from Robotaxis, after all, users can get assistance even if they are alone in the driverless vehicle.
Investor's Corner
Mizuho keeps Tesla (TSLA) “Outperform” rating but lowers price target
As per the Mizuho analyst, upcoming changes to EV incentives in the U.S. and China could affect Tesla’s unit growth more than previously expected.
Mizuho analyst Vijay Rakesh lowered Tesla’s (NASDAQ:TSLA) price target to $475 from $485, citing potential 2026 EV subsidy cuts in the U.S. and China that could pressure deliveries. The firm maintained its Outperform rating for the electric vehicle maker, however.
As per the Mizuho analyst, upcoming changes to EV incentives in the U.S. and China could affect Tesla’s unit growth more than previously expected. The U.S. accounted for roughly 37% of Tesla’s third-quarter 2025 sales, while China represented about 34%, making both markets highly sensitive to policy shifts. Potential 50% cuts to Chinese subsidies and reduced U.S. incentives affected the firm’s outlook.
With those pressures factored in, the firm now expects Tesla to deliver 1.75 million vehicles in 2026 and 2 million in 2027, slightly below consensus estimates of 1.82 million and 2.15 million, respectively. The analyst was cautiously optimistic, as near-term pressure from subsidies is there, but the company’s long-term tech roadmap remains very compelling.
Despite the revised target, Mizuho remained optimistic on Tesla’s long-term technology roadmap. The firm highlighted three major growth drivers into 2027: the broader adoption of Full Self-Driving V14, the expansion of Tesla’s Robotaxi service, and the commercialization of Optimus, the company’s humanoid robot.
“We are lowering TSLA Ests/PT to $475 with Potential BEV headwinds in 2026E. We believe into 2026E, US (~37% of TSLA 3Q25 sales) EV subsidy cuts and China (34% of TSLA 3Q25 sales) potential 50% EV subsidy cuts could be a headwind to EV deliveries.
“We are now estimating TSLA deliveries for 2026/27E at 1.75M/2.00M (slightly below cons. 1.82M/2.15M). We see some LT drivers with FSD v14 adoption for autonomous, robotaxi launches, and humanoid robots into 2027 driving strength,” the analyst noted.
News
Tesla’s Elon Musk posts updated Robotaxi fleet ramp for Austin, TX
Musk posted his update on social media platform X.
Elon Musk says Tesla will “roughly double” its supervised Robotaxi fleet in Austin next month as riders report long wait times and limited availability across the pilot program in the Texas city. Musk posted his update on social media platform X.
The move comes as Waymo accelerates its U.S. expansion with its fully driverless freeway service, intensifying competition in autonomous mobility.
Tesla to increase Austin Robotaxi fleet size
Tesla’s Robotaxi service in Austin continues to operate under supervised conditions, requiring a safety monitor in the front seat even as the company seeks regulatory approval to begin testing without human oversight. The current fleet is estimated at about 30 vehicles, StockTwists noted, and Musk’s commitment to doubling that figure follows widespread rider complaints about limited access and “High Service Demand” notifications.
Influencers and early users of the Robotaxi service have observed repeated failures to secure a ride during peak times, highlighting a supply bottleneck in one of Tesla’s most visible autonomy pilots. The expansion aims to provide more consistent availability as the company scales and gathers more real-world driving data, an advantage analysts often cite as a differentiator versus rivals.
Broader rollout plans
Tesla’s Robotaxi service has so far only been rolled out to Austin and the Bay Area, though reports have indicated that the electric vehicle maker is putting in a lot of effort to expand the service to other cities across the United States. Waymo, the Robotaxi service’s biggest competitor, has ramped its service to areas like the San Francisco Bay Area, Los Angeles, and Phoenix.
Analysts continue to highlight Tesla’s long-term autonomy potential due to its global fleet size, vertically integrated design, and immense real-world data. ARK Invest has maintained that Tesla Robotaxis could represent up to 90% of the company’s enterprise value by 2029. BTIG analysts, on the other hand, added that upcoming Full Self-Driving upgrades will enhance reasoning, particularly parking decisions, while Tesla pushes toward expansions in Austin, the Bay Area, and potentially 8 to 10 metro regions by the end of 2025.
Tesla takes a step towards removal of Robotaxi service’s safety drivers
Mizuho keeps Tesla (TSLA) “Outperform” rating but lowers price target
