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SpaceX CEO Elon Musk says major Starship engine bug is fixed as Raptor testing continues
SpaceX CEO Elon Musk has revealed the latest official photo of the company’s Raptor engine in action and indicated that a major technical issue with vibration appears to have been solved, hopefully paving the way for Starhopper’s first untethered flights.
Partly due to Musk’s own involvement in the program, SpaceX’s propulsion development team have struggled to get any single Raptor engine to survive more than 50-100 seconds of cumulative test fires. According to information from sources familiar with the program, Musk has enforced an exceptionally hardware-rich development program for the first full-scale Raptor engines to such an extent that several have been destroyed so completely that they could barely be used to inform design optimization work. Although likely more strenuous and inefficient than it needed to be, the exceptionally hardware-rich test program appears to have begun to show fruit, with the sixth engine built (SN06) passing its first tests without exhibiting signs of a problem that has plagued most of the five Raptors that came before it.
Resonance: not even once
In his tweet, Musk cryptically noted that a “600 Hz Raptor vibration problem” appears to have been fixed as of SN06’s first few static fire tests since arriving in McGregor, Texas. More likely than not, the self-taught SpaceX executive is referring to the hell that is mechanical resonance in complex machines and structures. Shown below, the Tacoma Narrows Bridge’s 1940 collapse – quite possibly the single most famous civil engineering failure of all time – is an iconic example of the unintuitive power of resonance in complex systems.
When it was inaugurated, the first Tacoma Narrows Bridge was one of the longest suspension bridges ever built and implemented new techniques and technologies that had never been tried at such a large scale. As Grady (Practical Engineer) aptly notes, mechanical resonance – in this case, triggered by consistent winds running through the Puget Sound – simply wasn’t something that period engineers knew they had to worry about. When rapidly pushing the envelope of engineering and construction, the chances of discovering entirely novel failure modes also increases – it’s simply one of the costs of extreme innovation.
Luckily for SpaceX, the company doesn’t have to clash with the immense challenge of testing something as large, complex, and expensive as a suspension bridge. Raptor, Starship, and Super Heavy need not necessarily be perfect on SpaceX’s first try, whereas civil bridges must essentially be flawless on the first try, despite being one of a kind. This is why SpaceX has been chewing through an average of one Raptor engine per month since February 2019 – by testing engines to destruction and aggressively comparing engineering expectations with observed behavior and post-test hardware conditions, rapid progress can (theoretically) be made.
Instead of spending another year or more analyzing models and testing subscale engines and components, SpaceX dove into integrated testing of a sort of minimum-viable-product Raptor design, accepting that the path to a flightworthy, finalized design would likely be paved with one or several dozen destroyed engines. According to Musk, the biggest pressing design deficiency involved a mode of mechanical resonance that may or may not have been predicted over the course of the design process. Dealing with unprecedented conditions, it’s not particularly surprising that some sort of new resonance mode was discovered in Raptor.
For the time being, SpaceX continues to work around the clock to build its first two orbital Starship prototypes (one in Texas, one in Florida), while also outfitting Starhopper and completing any possible engine-less tests in anticipation of the first flightworthy Raptor’s arrival. If Musk’s early analysis proves correct and Raptor SN06 makes it through lengthier static fire tests unscathed over the next week or so, the engine could potentially be delivered to Boca Chica as early as mid-July.
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Tesla has updated its Robotaxi app so riders can pick which vehicle they want before they book. The latest in-app screens now show two options side by side: the two-seat Cybercab and the four-seat Model Y.
A screenshot circulating Thursday shows the change in practice. In Austin, a rider could choose a gold Cybercab for two people or a Model Y for four. Tesla’s updated description calls Cybercab “our first purpose-built autonomous vehicle,” designed for safety, accessibility, and comfort, and says the lineup is available only through the Robotaxi app.
Tesla has updated their Robotaxi page in the App Store. You’ll be able to select if you want a Cybercab or Model Y Robotaxi.
“Our Robotaxi vehicle lineup now includes Cybercab, our first purpose-built autonomous vehicle. Designed for safety, accessibility and comfort, Cybercab… pic.twitter.com/Jff4klilDr
— Sawyer Merritt (@SawyerMerritt) September 3, 2026
The distinction is more than cosmetic, and it’s important to note that Robotaxi refers to the platform, while Cybercab refers to a vehicle.
Model Y Robotaxis have carried the service since it opened in Austin in mid-2025 and later expanded to Dallas, Houston, and parts of Florida. Those vehicles are converted production SUVs that still have steering wheels and pedals.
Cybercab is different. It has no driver controls, butterfly doors, a low seat height meant to work with wheelchairs, extra trunk space for assistive devices, and braille on the handles. Tesla has registered dozens of the two-seaters with Texas regulators in the days leading up to its September 3 Austin event.
Giving riders a choice lets Tesla match the vehicle to the trip. Most rides involve one or two people, which is where Cybercab is meant to be cheaper and more efficient to operate. Groups of three or four, or anyone who needs more space, can still request a Model Y.
The same app handles booking, payment, cabin settings, and, on Cybercab, features such as phone-based door opening and in-cabin voice controls.
The update does not mean every city suddenly has both cars available. Cybercab support is listed for Austin first, and the purpose-built fleet is still small compared with the existing Model Y roster. Even so, the app change marks a shift from a single-vehicle pilot to a mixed fleet.
Riders can now choose between the compact, purpose-built robotaxi and the familiar SUV that launched the service.
Tesla Cybercab sightings are broadening far and wide, well outside of downtown Austin, Texas, with autonomy in focus as the company plans to launch the all-electric, two-seater this evening in the Lone Star State.
Tesla is set to launch Cybercab to a small group of people this evening in a dedicated event in Austin, Texas. Public details on the event are relatively slim.
However, Tesla’s focus on Cybercab falls well outside of the downtown Austin area and is expanding well across the United States as things continue to move quickly with the company’s autonomous efforts in 2026. Today, various images of Cybercab fleets in interesting locations have started to circulate.
The most notable is a fleet of at least 20 Cybercabs at Miami International Airport in Florida. Spotted last night, the fleet is expansive and is indicative of a looming release of Cybercabs once regulatory boxes are checked off.
Tesla has already been operating the Robotaxi platform in Miami for several months, but this Cybercab fleet at the airport could be joining the ride-hailing platform as approvals arrive:
20+ Cybercabs spotted near Miami international airport. pic.twitter.com/ORLsw8yFhf
— Sawyer Merritt (@SawyerMerritt) September 3, 2026
Another fleet of Cybercabs was spotted at the Devon, PA showroom just outside of Philadelphia. We have seen several Cybercab units testing around the Philadelphia Metro Area, which is interesting considering Tesla does not have any active Robotaxi geofence in Pennsylvania.
Cybercab at the Devon location in PA has multiplied over the weekend. Seeing a few more test vehicles in the lot 👀 pic.twitter.com/DhJT4P1EkU
— Billy (@billykyle) August 22, 2026
Philadelphia would be an ideal location to test ride-hailing due to its dense tourist population, large, sprawling city layout, and to compete with other ride-hailing companies that operate in the city.
Expansive fleets of Cybercabs will be popping up in and around major cities throughout the rest of the year, if we were betting on it. Tesla has made it obvious that the Cybercab rollout will be aggressive and fast-paced, but within reason. Tesla is still prioritizing safety, so these testing phases will likely go on for some period of time before more members of the public are able to snag a Cybercab for a personal chariot.
The Tesla Model Y L is arguably the most hyped trim of the all-electric crossover, other than the Performance configuration that comes with white-knuckle speed and sports car-level handling.
However, it is not all perfect. Tesla owners in China who took delivery of the Model Y L, denoted with an L to highlight its longer wheelbase, are experiencing what they are referring to as “collapsing” of the rear wheels, as suspension issues appear to be an issue with some of the builds.
🚨 Model Y L owners in China report rear suspension sag
• Six-seat long-wheelbase Y. Shanghai. On sale since August 2025
• Owners say the rear tire-to-arch gap shrinks after mileage or a full load. Some cases after about 9,000 km loaded. Others near 30,000 km
• Tesla service… pic.twitter.com/Lr6i5Tbi07— Joe Hansen (@joehansen) September 1, 2026
The gap between the wheel arch and tire has narrowed to the point that “not even a single finger” could fit, according to a report from Car News China. The failures are not tied to a specific mileage, as one owner said that after just 9,000 kilometers (5,600 miles), they noticed the suspension issue when their car was fully loaded.
Another one had the issue at 30,000 kilometers (18,640 miles) and noticed that the wheel gap shrank to two fingers, so not as drastic as the person who reported a similar issue at 9,000 km.
Tesla Model Y L is gaining momentum in China’s premium segment
Along with the visual recognition of the issue, others are saying the sagging is causing abnormal wear on the inside of the tires. Extra weight and instant torque already provide additional stress on the tires in electric vehicles during normal operation, so it is no surprise that this is another complaint.
There has been no recall issued by Tesla, and the company has not yet publicly acknowledged the issue.
Some are suggesting that owners use a “finger test” to self-diagnose whether there is an issue with the suspension. There should be four fingers between the tire and the wheel well; anything less than that starts to get dicey.
Tesla Robotaxi riders will face the best dilemma when booking a ride
Tesla Cybercab sightings broaden well outside of Austin with autonomy in focus
