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SpaceX Starship booster’s ‘hot gas’ thrusters make first public appearance
‘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.
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.
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.
Just hours after Starship Flight 13 achieved a successful soft splashdown of its upper stage in the Indian Ocean on July 24, Elon Musk announced an ambitious next step for the company’s next launch of the rocket.
“Unless we discover problems after mission data review, SpaceX will attempt to catch the ship with the tower on [the] next flight,” the SpaceX CEO posted on X on Friday.
That “next flight” is expected to be Flight 14. The plan involves returning the Starship upper stage, commonly called the “ship,” to the Starbase launch tower in Texas and catching it mid-air using the same mechanical “chopsticks” arms that have already proven themselves with the Super Heavy booster.
Unless we discover problems after mission data review, SpaceX will attempt to catch the ship with the tower on next flight
— Elon Musk (@elonmusk) July 25, 2026
A successful catch would mark the first time an orbital-class upper stage has been recovered this way, advancing SpaceX’s goal of full and rapid reusability for the entire vehicle.
SpaceX has already demonstrated the tower-catch technique multiple times with Super Heavy. The first successful catch came on Flight 5 in October 2024, when Booster 12 was plucked from the sky by the Mechazilla arms. Subsequent flights, including those involving Boosters 14 and 15, repeated the feat. Several of those recovered boosters were later inspected, refurbished, and flown again, proving the system’s viability for quick turnaround.
Traditional reusable rockets, such as SpaceX’s own Falcon 9 or Blue Origin’s New Shepard, land on legs either on land or droneships. Rocket Lab has recovered its small Electron first stages by helicopter, but those are far lighter vehicles.
SpaceX Starship just nailed something it’s never done before
The China Academy of Launch Vehicle Technology (CALT), a subsidiary of the China Aerospace Science and Technology Corp. (CASC), completed a catch of its booster on July 10. They are the only entity besides SpaceX to attempt and complete the feat.
Flight 13 provided encouraging data. The ship executed a controlled reentry, flipped, and soft-landed intact in the ocean after deploying Starlink satellites, offering the first clear post-splashdown views of an undamaged heat shield. The Super Heavy booster, meanwhile, experienced a harder splashdown in the Gulf of Mexico.
Musk has previously stressed that ship catches would only follow multiple successful soft ocean landings to minimize risk of debris over land.
If Flight 14 succeeds, SpaceX would take a major stride toward routine, rapid reuse of both stages—critical for lowering launch costs and supporting ambitious plans for lunar and Mars missions. For now, teams are reviewing the Flight 13 data. Should everything check out, the next Starship flight could deliver one of the most spectacular recoveries in aerospace history.
In a move echoing its earlier commitment to open innovation, Tesla CEO Elon Musk announced recently that the company plans to make the design and software of its Model S and Model X fully open source.
This follows the same approach Tesla took with its original Roadster, releasing all available design, engineering, and diagnostic materials in November 2023 so that “whatever we have, you now have.”
Just as Tesla made the original Roadster design & software open source, we plan to do the same with Model S & X
— Elon Musk (@elonmusk) July 24, 2026
The Model S, introduced in 2012, was Tesla’s first mass-produced vehicle and a groundbreaking luxury electric sedan. It offered impressive range, rapid acceleration, and over-the-air software updates that redefined expectations for electric cars.
The Model X, launched in 2015, built on that foundation as a high-performance electric SUV notable for its distinctive falcon-wing doors, spacious interior, and advanced safety features. Both models served as flagships that helped establish Tesla as a leader in the EV industry and popularized long-range battery-electric vehicles.
Production of the Model S and Model X was wound down earlier in 2026, with manufacturing ending in the second quarter. Tesla redirected the Fremont factory space previously used for these vehicles toward higher-priority projects, including Optimus humanoid robots and the Cybercab autonomous vehicle.
By the time of Musk’s open-source announcement, custom orders had closed and only remaining inventory was available.
Open-sourcing the designs and software offers several clear advantages. Owners of these aging but still capable vehicles gain better access to technical documentation, diagnostic tools, and software resources, making independent repairs and modifications easier and more affordable.
Independent repair shops and third-party specialists can support the large existing fleet without relying solely on Tesla’s service network. Enthusiasts and engineers can study real-world implementations of Tesla’s battery, powertrain, and software systems, potentially accelerating broader industry progress in electric mobility.
The step aligns with Tesla’s 2014 patent pledge and its overall mission to advance sustainable transport by sharing hard-won knowledge rather than locking it behind proprietary walls.
By releasing these materials now that the models have left production, Tesla ensures continued support for its early adopters while freeing internal resources for future technologies. The open-source release of the original Roadster already enabled simulations, community projects, and deeper technical understanding.
Extending that practice to the Model S and Model X should deliver similar benefits on a larger scale, helping keep these influential vehicles relevant and repairable for years to come
Tesla flexed one incredible Robotaxi metric during the Q2 Earnings Call that skeptics have to hate to hear. The company’s platform has already driven more than 380,000 miles of unsupervised ride-hailing across several states with no notable incidents.
During the company’s Q2 Earnings Call on Wednesday, Vice President of AI, Ashok Elluswamy, said:
“First of all, I’d like to state that the Robotaxi program has been operating extremely well. Especially in terms of safety, the program has had an impeccable safety record. We have driven more than 380,000 miles of unsupervised Robotaxi, now across six cities in two different states. We have had zero notable incidents. Any reports have been of other actors impacting us when we were stationary. I like to emphasize how safe the operation has been so far. Zero notable incidents over 380,000 miles.”
Elluswamy’s claim over Robotaxi miles is a significant milestone for Tesla in the grand scheme, especially considering this is a sizeable number of miles without any incident.
0 notable incidents across over 380,000 miles traveled by Robotaxi
— Tesla (@Tesla) July 22, 2026
Tesla’s self-driving approach is much different than that of other companies. Tesla has maintained that vision is the only thing needed to have a solid and effective self-driving suite. Many self-driving companies utilize things like LiDAR, sensors, and other elements to improve performance, but Elluswamy sent a jab at those who believe it’s needed.
“Historically, the so-called experts have always claimed that you need LiDARs, radars, HD maps, and the entire kitchen sink to drive safely. Here we show that such is not true. You can have safe, comfortable, and affordable autonomy with just cameras. This record should be a huge validation of Tesla’s entire AI approach.”
The feat of accumulating this many miles without any driver behind the wheel is impressive. The thing is, Tesla is also doing this across several different locations, with varying traffic rules, pedestrian levels, weather patterns, and other important factors.
While Tesla is not ready to roll out an unsupervised platform completely, it is a slow but steady indication that the company is well on its way to figuring things out.
The company’s attitude toward expansion is slow, safe, and controlled, and despite this huge milestone, it will still be some time until we see Tesla truly unleash unsupervised rides more aggressively.
SpaceX wants to catch Starship for launch 14, Elon Musk says
Tesla to open source Model S and Model X designs and software
