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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.
Elon Musk
Rumored SpaceX-xAI merger gets apparent confirmation from Elon Musk
The comment follows reports that the rocket maker is weighing a transaction that could further consolidate Musk’s space and AI ventures.
Elon Musk appeared to confirm reports that SpaceX is exploring a potential merger with artificial intelligence startup xAI by responding positively to a post about the reported transaction on X.
Musk’s comment follows reports that the rocket maker is weighing a transaction that could further consolidate his space and AI ventures.
SpaceX xAI merger
As per a recent Reuters report, SpaceX has held discussions about merging with xAI, with the proposed structure potentially involving an exchange of xAI shares for SpaceX stock. The value, structure, and timing of any deal have not been finalized, and no agreement has been signed.
Musk appeared to acknowledge the report in a brief reply on X, responding “Yeah” to a post that described SpaceX as a future “Dyson Swarm company.” The comment references a Dyson Swarm, a sci-fi megastructure concept that consists of a massive network of satellites or structures that orbit a celestial body to harness its energy.
Reuters noted that two entities were formed in Nevada on January 21 to facilitate a potential transaction for the possible SpaceX-xAI merger. The discussions remain ongoing, and a transaction is not yet guaranteed, however.
AI and space infrastructure
A potential merger with xAI would align with Musk’s stated strategy of integrating artificial intelligence development with space-based systems. Musk has previously said that space-based infrastructure could support large-scale computing by leveraging continuous solar energy, an approach he has framed as economically scalable over time.
xAI already has operational ties to Musk’s other companies. The startup develops Grok, a large language model that holds a U.S. Department of Defense contract valued at up to $200 million. AI also plays a central role in SpaceX’s Starlink and Starshield satellite programs, which rely on automation and machine learning for network management and national security applications.
Musk has previously consolidated his businesses through share-based transactions, including Tesla’s acquisition of SolarCity in 2016 and xAI’s acquisition of X last year. Bloomberg has also claimed that Musk is considering a merger between SpaceX and Tesla in the future.
Tesla analyst Gary Black of The Future Fund claims that the company is making a big mistake getting rid of the Model S and Model X. Instead, he believes another vehicle within the company’s lineup should be discontinued: the Cybertruck.
Black divested The Future Fund from all Tesla holdings last year, but he still covers the stock as an analyst as it falls in the technology and autonomy sectors, which he covers.
In a new comment on Thursday, Black said the Cybertruck should be the vehicle Tesla gets rid of due to the negatives it has drawn to the company.
The Cybertruck is also selling in an underwhelming fashion considering the production capacity Tesla has set aside for it. It’s worth noting it is still the best-selling electric pickup on the market, and it has outlasted other EV truck projects as other manufacturers are receding their efforts.
Black said:
“IMHO it’s a mistake to keep Tesla Cybertruck which has negative brand equity and sold 10,000 units last year, and discontinue S/X which have strong repeat brand loyalty and together sold 30K units and are highly profitable. Why not discontinue CT and covert S/X to be fully autonomous?”
IMHO it’s a mistake to keep $TSLA Cybertruck which has negative brand equity and sold 10,000 units last year, and discontinue S/X which have strong repeat brand loyalty and together sold 30K units and are highly profitable. Why not discontinue CT and covert S/X to be fully…
— Gary Black (@garyblack00) January 29, 2026
On Wednesday, CEO Elon Musk confirmed that Tesla planned to transition Model S and Model X production lines at the Fremont Factory to handle manufacturing efforts of the Optimus Gen 3 robot.
Musk said that it was time to wind down the S and X programs “with an honorable discharge,” also noting that the two cars are not major contributors to Tesla’s mission any longer, as its automotive division is more focused on autonomy, which will be handled by Model 3, Model Y, and Cybercab.
Tesla begins Cybertruck deliveries in a new region for the first time
The news has drawn conflicting perspectives, with many Tesla fans upset about the decision, especially as it ends the production of the largest car in the company’s lineup. Tesla’s focus is on smaller ride-sharing vehicles, especially as the vast majority of rides consist of two or fewer passengers.
The S and X do not fit in these plans.
Nevertheless, the Cybertruck fits in Tesla’s future plans. Musk said the pickup will be needed for the transportation of local goods. Musk also said Cybertruck would be transitioned to an autonomous line.
In a groundbreaking new report from Reuters, SpaceX is reportedly discussing merger possibilities with xAI ahead of the space exploration company’s plans to IPO later this year, in what would be a blockbuster move.
The outlet said it would combine rockets and Starlink satellites, as well as the X social media platform and AI project Grok under one roof. The report cites “a person briefed on the matter and two recent company filings seen by Reuters.”
Musk, nor SpaceX or xAI, have commented on the report, so, as of now, it is unconfirmed.
With that being said, the proposed merger would bring shares of xAI in exchange for shares of SpaceX. Both companies were registered in Nevada to expedite the transaction, according to the report.
On January 21, both entities were registered in Nevada. The report continues:
“One of them, a limited liability company, lists SpaceX and Bret Johnsen, the company’s chief financial officer, as managing members, while the other lists Johnsen as the company’s only officer, the filings show.”
The source also stated that some xAI executives could be given the option to receive cash in lieu of SpaceX stock. No agreement has been reached, nothing has been signed, and the timing and structure, as well as other important details, have not been finalized.
SpaceX is valued at $800 billion and is the most valuable privately held company, while xAI is valued at $230 billion as of November. SpaceX could be going public later this year, as Musk has said as recently as December that the company would offer its stock publicly.
The plans could help move along plans for large-scale data centers in space, something Musk has discussed on several occasions over the past few months.
At the World Economic Forum last week, Musk said:
“It’s a no-brainer for building solar-powered AI data centers in space, because as I mentioned, it’s also very cold in space. The net effect is that the lowest cost place to put AI will be space and that will be true within two to three years, three at the latest.”
He also said on X that “the most important thing in the next 3-4 years is data centers in space.”
If the report is true and the two companies end up coming together, it would not be the first time Musk’s companies have ended up coming together. He used Tesla stock to purchase SolarCity back in 2016. Last year, X became part of xAI in a share swap.
Rumored SpaceX-xAI merger gets apparent confirmation from Elon Musk
Tesla analyst claims another vehicle, not Model S and X, should be discontinued
