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SpaceX Starship booster’s ‘hot gas’ thrusters make first public appearance

While different in several key ways, new methane-oxygen thrusters recently spotted for the first time on Starship hardware are likely similar to Raptor and Crew Dragon's SuperDraco abort thrusters. (SpaceX)

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‘Hot gas’ thrusters meant to boost the efficiency of SpaceX’s Starship spacecraft and Super Heavy boosters have been spotted in public for the first time.

On the evening of June 21st, spaceflight photographer Brady Kenniston – on assignment for NASASpaceflight – caught the first glimpses ever of what amounts to the newest rocket engine designed and built by SpaceX. As yet unnamed, SpaceX CEO Elon Musk has consistently referred to the new engine as a “hot gas thruster” for several years, though virtually no concrete details have ever been shared.

The reason behind the lack of major visible progress is simple enough: until Starship is ready for serious orbital testing, hot-gas thrusters just aren’t necessary. Instead, SpaceX has relied on tried and true cold gas thrusters derived – or quite literally taken, in the case of Starhopper – from those used on Falcon 9 and Falcon Heavy boosters to maintain attitude control in space and safely land back on Earth.

For Starhopper and Starships SN5 and SN6, all three of which focused on simple hop tests, those cold-gas thrusters primarily augmented Raptor’s thrust vectoring capabilities by fine-tuning vehicle rotation and attitude. On Starships SN8, SN9, SN10, SN11, and SN15, cold-gas thrusters played a more substantial role in their more complex medium-altitude test flights, flipping each ship horizontal at apogee, helping to maintain stability during skydiver-style freefalls back to Earth, and augmenting three Raptor engines during the final landing flip and landing burn.

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By all appearances, the thrusters did their jobs perfectly on all nine test flights. However, those eight suborbital prototypes could all afford to expend large portions of their mass budgets on a plethora of pressure vessels filled with tons of nitrogen gas. More importantly, empty Starships and their Super Heavy boosters are expected to weigh anywhere from 10-50 times more than Falcon 9’s booster and upper stage, and SpaceX’s suborbital prototypes have also required much less performance (delta V) than operational ships and boosters will need.

https://www.youtube.com/watch?v=y23V1pYq0uw

Cold gas (nitrogen) thrusters are too inefficient and the exponential aspects of rocket engineering too cruel for what works on Falcon to efficiently meet the needs of Starship and Super Heavy. SpaceX’s long-planned solution has been the development of a bipropellant thruster that would borrow from Raptor expertise and use the same methane and oxygen propellant – albeit in their high-pressure gaseous forms. If properly realized, such a thruster could offer around five times the efficiency and thrust of a similarly-sized cold-gas system – a boon for maneuvering and manipulating massive 100-250 ton (~250,000-550,000 lb) ships and boosters in space.

In theory, moving from nitrogen to methalox thrusters also means that Starship could refuel its thrusters using a tiny fraction of the vast supply of liquid methane and oxygen propellant it will already be carrying to the Moon or Mars. Ultimately, though, Musk says that those hot gas attitude control thrusters will debut on the Super Heavy booster assigned to Starship’s first orbital test flight. While SpaceX’s initial July target now appears to be out of the question, all flight and pad hardware could still be ready to launch as early as August or September.

Update: One month after Elon Musk stated that SpaceX was “aiming” to have hot gas thrusters on the first flightworthy Super Heavy booster, the CEO says those thrusters would be “an unnecessary complication for now” and “are being removed to speed up time to” Starship’s first orbital launch.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Tesla FSD (Supervised) fleet passes 8.4 billion cumulative miles

The figure appears on Tesla’s official safety page, which tracks performance data for FSD (Supervised) and other safety technologies.

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Credit: Tesla

Tesla’s Full Self-Driving (Supervised) system has now surpassed 8.4 billion cumulative miles.

The figure appears on Tesla’s official safety page, which tracks performance data for FSD (Supervised) and other safety technologies.

Tesla has long emphasized that large-scale real-world data is central to improving its neural network-based approach to autonomy. Each mile driven with FSD (Supervised) engaged contributes additional edge cases and scenario training for the system.

Credit: Tesla

The milestone also brings Tesla closer to a benchmark previously outlined by CEO Elon Musk. Musk has stated that roughly 10 billion miles of training data may be needed to achieve safe unsupervised self-driving at scale, citing the “long tail” of rare but complex driving situations that must be learned through experience.

The growth curve of FSD Supervised’s cumulative miles over the past five years has been notable. 

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As noted in data shared by Tesla watcher Sawyer Merritt, annual FSD (Supervised) miles have increased from roughly 6 million in 2021 to 80 million in 2022, 670 million in 2023, 2.25 billion in 2024, and 4.25 billion in 2025. In just the first 50 days of 2026, Tesla owners logged another 1 billion miles.

At the current pace, the fleet is trending towards hitting about 10 billion FSD Supervised miles this year. The increase has been driven by Tesla’s growing vehicle fleet, periodic free trials, and expanding Robotaxi operations, among others.

With the fleet now past 8.4 billion cumulative miles, Tesla’s supervised system is approaching that threshold, even as regulatory approval for fully unsupervised deployment remains subject to further validation and oversight.

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Elon Musk fires back after Wikipedia co-founder claims neutrality and dubs Grokipedia “ridiculous”

Musk’s response to Wales’ comments, which were posted on social media platform X, was short and direct: “Famous last words.”

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UK Government, CC BY 2.0 , via Wikimedia Commons

Elon Musk fired back at Wikipedia co-founder Jimmy Wales after the longtime online encyclopedia leader dismissed xAI’s new AI-powered alternative, Grokipedia, as a “ridiculous” idea that is bound to fail.

Musk’s response to Wales’ comments, which were posted on social media platform X, was short and direct: “Famous last words.”

Wales made the comments while answering questions about Wikipedia’s neutrality. According to Wales, Wikipedia prides itself on neutrality. 

“One of our core values at Wikipedia is neutrality. A neutral point of view is non-negotiable. It’s in the community, unquestioned… The idea that we’ve become somehow ‘Wokepidea’ is just not true,” Wales said.

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When asked about potential competition from Grokipedia, Wales downplayed the situation. “There is no competition. I don’t know if anyone uses Grokipedia. I think it is a ridiculous idea that will never work,” Wales wrote.

After Grokipedia went live, Larry Sanger, also a co-founder of Wikipedia, wrote on X that his initial impression of the AI-powered Wikipedia alternative was “very OK.”

“My initial impression, looking at my own article and poking around here and there, is that Grokipedia is very OK. The jury’s still out as to whether it’s actually better than Wikipedia. But at this point I would have to say ‘maybe!’” Sanger stated.

Musk responded to Sanger’s assessment by saying it was “accurate.” In a separate post, he added that even in its V0.1 form, Grokipedia was already better than Wikipedia.

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During a past appearance on the Tucker Carlson Show, Sanger argued that Wikipedia has drifted from its original vision, citing concerns about how its “Reliable sources/Perennial sources” framework categorizes publications by perceived credibility. As per Sanger, Wikipedia’s “Reliable sources/Perennial sources” list leans heavily left, with conservative publications getting effectively blacklisted in favor of their more liberal counterparts.

As of writing, Grokipedia has reportedly surpassed 80% of English Wikipedia’s article count.

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Tesla Sweden appeals after grid company refuses to restore existing Supercharger due to union strike

The charging site was previously functioning before it was temporarily disconnected in April last year for electrical safety reasons.

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Credit: Tesla Charging

Tesla Sweden is seeking regulatory intervention after a Swedish power grid company refused to reconnect an already operational Supercharger station in Åre due to ongoing union sympathy actions.

The charging site was previously functioning before it was temporarily disconnected in April last year for electrical safety reasons. A temporary construction power cabinet supplying the station had fallen over, described by Tesla as occurring “under unclear circumstances.” The power was then cut at the request of Tesla’s installation contractor to allow safe repair work.

While the safety issue was resolved, the station has not been brought back online. Stefan Sedin, CEO of Jämtkraft elnät, told Dagens Arbete (DA) that power will not be restored to the existing Supercharger station as long as the electric vehicle maker’s union issues are ongoing. 

“One of our installers noticed that the construction power had been backed up and was on the ground. We asked Tesla to fix the system, and their installation company in turn asked us to cut the power so that they could do the work safely. 

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“When everything was restored, the question arose: ‘Wait a minute, can we reconnect the station to the electricity grid? Or what does the notice actually say?’ We consulted with our employer organization, who were clear that as long as sympathy measures are in place, we cannot reconnect this facility,” Sedin said. 

The union’s sympathy actions, which began in March 2024, apply to work involving “planning, preparation, new connections, grid expansion, service, maintenance and repairs” of Tesla’s charging infrastructure in Sweden.

Tesla Sweden has argued that reconnecting an existing facility is not equivalent to establishing a new grid connection. In a filing to the Swedish Energy Market Inspectorate, the company stated that reconnecting the installation “is therefore not covered by the sympathy measures and cannot therefore constitute a reason for not reconnecting the facility to the electricity grid.”

Sedin, for his part, noted that Tesla’s issue with the Supercharger is quite unique. And while Jämtkraft elnät itself has no issue with Tesla, its actions are based on the unions’ sympathy measures against the electric vehicle maker. 

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“This is absolutely the first time that I have been involved in matters relating to union conflicts or sympathy measures. That is why we have relied entirely on the assessment of our employer organization. This is not something that we have made any decisions about ourselves at all. 

“It is not that Jämtkraft elnät has a conflict with Tesla, but our actions are based on these sympathy measures. Should it turn out that we have made an incorrect assessment, we will correct ourselves. It is no more difficult than that for us,” the executive said. 

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