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SpaceX to replace Falcon 9’s titanium grid fins with steel on Starship’s Super Heavy booster
Following a question on Twitter about how SpaceX intends to manufacture the truly massive grid fins shown in renders of Starship’s Super Heavy booster, CEO Elon Musk revealed that SpaceX will build them out of welded steel.
For the first several years of Falcon 9 and Falcon Heavy booster recovery operations, SpaceX built grid fins – used for maneuvering the rockets at high speeds – out of aluminum. With Falcon 9 Block 5, aluminum grid fins were phased out entirely in favor of larger titanium fins, necessitated by exceptionally high-speed reentries that nearly melted through the aluminum fins on several occasions. Now, SpaceX wants to move from titanium to steel fins for its next-generation Starship launch vehicle.
Welded steel— Elon Musk (@elonmusk) October 3, 2019
In response to the Twitter user’s question, Musk simply stated that Super Heavy’s grid fins would be manufactured out of “welded steel”, certainly keeping with the CEO’s now well-known love for the material. In October 2018, Musk finally managed to convince most of the senior engineers reporting to him that – despite years of work and full-scale testing – SpaceX needed to radically redesign Starship.
Prior to this radical change, SpaceX had spent at least 2-3 years on a Starship design (formerly Big F_____ Spaceship; BFS) made almost entirely out of carbon fiber composites, an extremely lightweight material that can be optimized for high strength. However, as Musk ultimately concluded in late 2018, although carbon composites are undeniably light and strong (optimal for spaceflight), they have extremely low heat tolerance and can react violently with supercooled liquid oxygen. Built almost entirely out of aluminum alloys with similarly low melting points, Falcon 9 has also struggled with the challenges posed by material choices, made far more difficult by the need to recover and reuse orbital-class rocket stages.
Musk ultimately decided that redesigning Starship with steel (alloys with particularly high melting points and good strength) was the right way to go. According to Musk, the high-quality carbon fiber composites SpaceX was originally pursuing cost something like $130,000 per metric ton, translating to a truly gobsmacking cost – accounting for unavoidable wastage – of $400M-$500M or more just to buy the materials needed to build a single Starship and Super Heavy booster. Steel, on the other hand, is quite literally 50 times cheaper, costing SpaceX around $2500 per ton, or as little as $10M in structural materials for each ship/booster pair.
Man of Stainless Steel
Speaking at a September 28th presentation on the 2019 status of Starship’s design, CEO Elon Musk couldn’t praise his decision to move to stainless steel enough, describing it as likely being the single best design decision he has ever made. It remains to be seen if the eccentric self-taught engineer’s decision was the correct one, but the progress SpaceX has made in just 10-11 months is undeniable. SpaceX has gone from a nearly blank slate to Starhopper’s 150m (500ft) test flight in ~6 months and gone from nothing to Starship Mk1 in another 6 or so months.
According to Musk, the properties of stainless steel – mainly a high melting point/working temperature and a tendency to strengthen at cryogenic temperatures – mean that the relatively heavy material is able to produce a launch vehicle that could eventually be far lighter and higher-performance than one made with carbon composites (BFR) or aluminum alloys (Falcon 9). Thanks to those properties, Starship/Super Heavy will become much stronger when filled with cold propellant and will also require little to no external heat shielding on its leeward half, whereas a reusable Al/composite rocket would require major thermal protection on nearly all exposed surfaces.
As part of the move to remove any ultra-expensive nonessential materials from the designs of Starship and Super Heavy, Musk has apparently also turned his gaze on the booster’s grid fins. As described at the top of this article, SpaceX replaced Falcon 9’s aluminum grid fins with titanium fins, requiring the company to create the largest single-piece titanium casting in the world. Musk has repeatedly indicated that each grid fin is extremely expensive.
In light of their expense, Musk (or SpaceX) has seemingly decided that future (larger?) SpaceX rockets will try to avoid large, titanium castings. Super Heavy nevertheless still needs massive grid fins: official renders published by SpaceX last month revealed a new diamond shape for the booster’s fins, and Musk later took to Twitter to reveal that they would be made out of welded steel instead of titanium.
Based on SpaceX’s official 2019 Super Heavy renders, the booster’s grid fins measure approximately 7m by 3m (23 ft by 10 ft), dwarfing Falcon 9’s titanium fins (perhaps 2m by 1.2m) with something like 8-10 times the surface area. Although 301-series stainless steel has a melting point and heat capacity roughly 15% lower than Grade 5 titanium, its strength characteristics are otherwise similar, while also remaining mechanically functional at almost three times the working temperature of titanium (840C vs. 330C).
Most importantly, not only is 301 steel roughly 15-20 times cheaper than titanium, but the process of fabricating large steel components – particularly with welding instead of casting – is dramatically faster, easier, and cheaper than working with and forming titanium. With their reasonably similar properties and the increased size of Super Heavy, it’s likely that steel grid fins would exhibit little to no ablation during even the hottest atmospheric reentries, and it would nevertheless be extremely easy and cheap to either repair or replace fins in the unlikely event of damage.
Given just how quickly and relatively easily SpaceX has built full-scale flight hardware out of steel and assuming there are no technical showstoppers caused by changing scales, it wouldn’t be surprising in the slightest to see SpaceX fabricate and test welded steel grid fins on Falcon 9 boosters in the near future.
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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
