SpaceX
SpaceX’s Starship hopper spotted with trio of dual-bell Raptor engines
Following a brief ‘hop’ (via crane) off of a concrete build stand, the aft section of SpaceX’s first full-scale Starship hopper (Starhopper?) revealed that SpaceX technicians have already installed what appear to be three real Raptor engines, presumably the first time the propulsion system has ever been mounted to something that might eventually fly.
For a number of reasons, there is a strong chance that these Raptors are actually just boilerplate placeholders standing in as structural guides for the real deal some months down the line. On the other hand, there are also a number of reasons to assume that these apparent engines are indeed real Raptors.
Star ship hopper might be a bit bigger than we thought and with the crane placements over the nose end of the vehicle. This could suggest, @SpaceX are planning to move the segment elsewhere perhaps to the welding stand? We will have to wait and see. (Austin Barnard📸) #2019🚀 pic.twitter.com/kn8hhUPWCU
— Austin Barnard🚀 (@austinbarnard45) January 1, 2019
Despite an already shocking series of rapid-fire developments in the South Texas Starhopper saga, the abrupt appearance of what appears to be three Raptor engines – mirroring CEO Elon Musk’s recent statement that the test vehicle would sport three Raptors – is by far the most unexpected moment yet for the prototype Starship. Purportedly a full-scale prototype of BFR’s upper stage/spaceship (now known as Starship), Musk indicated over the last two weeks that the hopper has been designed to perform a number of hop tests in which the craft’s three Raptors would power it to a range of (relatively low) altitudes above Boca Chica, Texas.
According to a recent FCC filing related to this test program, SpaceX is currently seeking a license for Starship hop tests that will not exceed 5 km (3.1 mi) in altitude and/or 6 minutes in duration. There is admittedly nothing mentioned about the maximum allowed velocity during those tests, but – much like Blue Origin performs supersonic tests of New Shepard in Cape Horn, Texas – SpaceX will likely seek and be granted permission to break the sound barrier during those hypothetical tests. Nevertheless, a 5km ceiling is a fairly significant cap on the range of performance Starhopper will be able to test – accelerating vertically at 2Gs, Starhopper could travel from sea level to 5km in less than 30 seconds while reaching speeds no higher than Mach 1-1.5.
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- SpaceX technicians and engineers are continuing to work at a breakneck pace on Starhopper. (NASASpaceflight – bocachicagal)
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- At this rate, the hopper will likely wind up around 40m (130 feet) tall. (NASASpaceflight – bocachicagal)
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- A close examination of these three engine-like protrusions suggests a level of fit and finish far exceeding a boilerplate stand-in. (NASASpaceflight – bocachicagal)
Combined with the apparent fact that this Starhopper’s fins seem unlikely to ever actuate (i.e. no aerodynamic control surfaces), it’s probable that this ad hoc prototype is only meant to perform a very limited range of hop tests, perhaps as basic as ironing out the kinks of operating a trio of gimballed Raptors and ensuring that they can safely and reliably launch, hover, and land a very large Starship-shaped mass simulator. Falcon 9’s Grasshopper and F9R reusability testbeds performed a very similar task some five years ago, offering SpaceX engineers the opportunity to optimize software and hardware needed to reliably recover real orbital-class rockets after launch. Although Falcon 9 has nine gimballed Merlin 1D engines, SpaceX has long sided with the sole center Merlin as the dedicated landing engine and has only briefly experimented with triple-Merlin landing burns.
Dual-expansion whaaaaat?
According to Musk, Raptor – an advanced liquid methane and oxygen engine with a uniquely efficient propulsion cycle – was expected to produce an impressive ~2000 kN (200 ton, 450K lbf) of thrust in its finished form as of September 2018. However, Musk also mentioned in a late-2017 Reddit AMA that SpaceX engineers were modifying the ship’s design to ensure engine-out reliability during all regimes of flight, landing in particular. To accomplish this feat with an engine as powerful as Raptor, two or three Raptors – capable of producing as much as 600 tons of thrust total – would need to reliably throttle as low as 25%, assuming a landing mass of around 150t. To allow a nearly empty ship (~100t) to still reliably land with three Raptors ignited, the engines would need to be able to throttle to 20% or less.
Known as deep throttling in rocketry, ensuring stable combustion and thrust at 20% (let alone 40%) throttle is an extraordinarily challenging feat, often subjecting engines to forces that can literally tear non-optimized hardware apart. To achieve such a deep throttle capability without excessively disrupting the engine’s design, SpaceX appears to have potentially sided with less efficient but extremely simple alternative, known as a dual-bell (or dual-expansion) rocket nozzle. A 1999 Rocketdyne paper concisely explained the primary draws of such a nozzle:
“The [altitude-compensating] dual-bell nozzle offers a unique combination of performance, simplicity, low weight, and ease of cooling” – Horn & Fisher, 1999
Exactly
— Elon Musk (@elonmusk) December 27, 2018
Given that SpaceX has decided to delay the introduction and certification of a vacuum-optimized Raptor engine, choosing to instead use the same Raptor on both BFR stages, something like a dual-bell nozzle would be one of the best possible ways for the company to retain some of the efficiency benefits of a vacuum engine while also drastically improving design simplicity, ease of manufacturing, and cutting development time. Aside from offering efficiency gains by way of altitude compensation, a dual-bell nozzle also happens to enable a given engine to operate a much wider throttle range by mitigating problems with flow separation and instability.
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- A gif of Raptor throttling over the course of a 90+ second static-fire test in McGregor, Texas. (SpaceX)
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- Note that Merlin 1D and prior Raptor prototypes both feature traditional single nozzles. (Pauline Acalin)
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- An overview of dual-bell and deflection nozzles. Raptor appears to have now graduated to the former style. (Johan Steelant, 2011)
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- Starhopper’s Raptors feature a very distinct seam and second curve, indicative of a dual-bell nozzle. (NASASpaceflight /u/bocachicagal)
For Starhopper and Starship, both aspects are an undeniable net-gain and it’s entirely possible that these dual-bell nozzles – if successfully demonstrated – could find their way onto Falcon 9 and Falcon Heavy to further boost their booster performance and efficiency.
For prompt updates, on-the-ground perspectives, and unique glimpses of SpaceX’s rocket recovery fleet check out our brand new LaunchPad and LandingZone newsletters!
Elon Musk
Elon Musk’s TERAFAB project: Everything you need to know
The CEO has hinted heavily for several quarters that it would probably need to produce its own computing power to stay up to speed on the demand it is facing for its projects. It is now taking matters into its own hands.
On Sunday, Elon Musk formally made TERAFAB official—a groundbreaking $20-25 billion joint venture uniting Tesla, SpaceX, and xAI, three of the world’s richest man’s most significant and powerful ventures.
Musk described the project as “the most epic chip building exercise in history by far.”
Elon Musk launches TERAFAB: The $25B Tesla-SpaceXAI chip factory that will rewire the AI industry
The initiative aims to produce over one terawatt of AI compute annually, dwarfing the global industry’s current output of roughly 20 gigawatts per year. Musk framed the effort as “the next step towards becoming a galactic civilization,” positioning it as essential for scaling humanity into a multi-planetary species.
The Need for TERAFAB
Existing chip suppliers such as TSMC, Samsung, and Micron cannot expand quickly enough to meet the explosive demand for AI hardware.
We’re building TERAFAB to close the gap between today’s chip production & the future’s demand – a future among the stars.
Join us → https://t.co/512DIlqNgY pic.twitter.com/ATr0e0pRDJ
— SpaceX (@SpaceX) March 22, 2026
Musk explained the situation clearly:
“We’re very grateful to our existing supply chain… but there’s a maximum rate at which they’re comfortable expanding. We either build the Terafab or we don’t have the chips, and we need the chips, so we build the Terafab.”
The CEO has hinted heavily for several quarters that it would probably need to produce its own computing power to stay up to speed on the demand it is facing for its projects. It is now taking matters into its own hands.
Chip Types and Production Goals
The facility will manufacture two specialized chip families, according to the presentation:
- Edge-inference AI5 and AI6 processors optimized for Tesla’s Optimus humanoid robots and Full Self-Driving systems in vehicles and Robotaxis
- High-power D3 chips hardened for space environments
Musk outlined annual output targets, which are between 100 and 200 gigawatts of terrestrial compute for robotics, supporting Musk’s vision of producing 1-10 billion Optimus units per year, and the majority (80%) of chips dedicated to orbital AI data centers. Overall, TERAFAB aims to produce 100-200 billion custom AI and memory chips each year.
Scale and Strategy
The size of the TERAFAB project will be remarkable, as Musk indicated after the presentation that the entire Gigafactory Texas campus would not be large enough to fit the needs of the project. In fact, Musk said it would be around 100 million square feet in size, the equivalent of 15 Pentagons or three Central Parks.
Yes, the one in New York City.
Construction will begin with an “advanced technology fab” on the Giga Texas campus in Austin, enabling rapid iteration: design a chip, fabricate lithography masks, produce and test wafers, all within days.
However, the full-scale TERAFAB requires thousands of acres and over 10 gigawatts of power, far exceeding what Giga Texas can accommodate. Musk stated:
“We couldn’t possibly fit the Terafab on the GigaTexas campus. It will be far bigger than everything else combined there.”
Multiple large sites are currently under consideration, but this will need a sprawling land mass to get started.
The sheer scale of TERAFAB is going to be insane.
Elon said it wouldn’t be suitable for anywhere on Giga Texas property because it’s too big:
“We couldn’t possibly fit the Terafab on the GigaTexas campus. It will be far bigger than everything else combined there.
Several… pic.twitter.com/79GbhNNuf4
— TESLARATI (@Teslarati) March 23, 2026
Key Applications
TERAFAB will be a crucial part of the development of some of Tesla’s most valuable projects, including Optimus and data center development, especially from an orbital standpoint. For that reason, we will break this down into Terrestrial and Orbital applications:
- Terrestrial: Powers autonomous vehicle fleets and billions of Optimus robots performing physical labor
- Orbital: Starship will launch massive AI satellite constellations, starting with 100-kilowatt “Mini” units, and scaling to larger Megawatt models, creating the world’s largest data center in low-Earth orbit.
Space-based advantages include five times greater solar irradiance, efficient vacuum heat rejection, and freedom from terrestrial grid constraints (U.S. electricity generation totals just 0.5 terawatts). Musk emphasized the principle:
“Quantity has a quality all its own.”
We wrote about SpaceX’s recent filing with the FCC for 1 million orbital data center plans.
Strategic Vision
TERAFAB represents vertical integration at an unprecedented scale, combining AI hardware, robotics, and orbital infrastructure.
Musk described the project as “the final missing piece of the puzzle.” With production ramping toward 2027, TERAFAB is set to accelerate an era of abundance, transforming science fiction into reality and positioning Musk’s companies at the forefront of galactic-scale innovation.
Elon Musk
Elon Musk launches TERAFAB: The $25B Tesla-SpaceXAI chip factory that will rewire the AI industry
Tesla, SpaceX, and xAI unveiled TERAFAB, a $25B chip factory targeting one terawatt of AI compute annually.
Elon Musk took the stage over the weekend at the defunct Seaholm Power Plant in Austin, Texas, to officially unveil TERAFAB, a $20-25 billion joint venture between Tesla, SpaceX, and xAI that he described as “the most epic chip building exercise in history by far.” The announcement marks the most ambitious infrastructure bet Musk has made since Gigafactory 1 in Sparks, Nevada, and it fuses three of his companies into a single, vertically integrated AI hardware machine for the first time.
TERAFAB is designed to consolidate every stage of semiconductor production under one roof, including chip design, lithography, fabrication, memory production, advanced packaging, and testing. At full capacity, the facility would scale to roughly 70% of the global output from the current world’s largest semiconductor foundry from Taiwan Semiconductor Manufacturing Company (TSMC).
Elon Musk’s stated goal is one terawatt of computing power annually, split between Tesla’s AI5 inference chips for vehicles and Optimus robots, and D3 chips built specifically for SpaceXAI’s orbital satellite constellation.
Tesla Terafab set for launch: Inside the $20B AI chip factory that will reshape the auto industry
The logic behind the merger of these three entities is rooted in a supply chain crisis Musk has been signaling for over a year. At Tesla’s Q4 2025 earnings call, he warned investors that external chip capacity from TSMC, Samsung, and Micron would hit a ceiling within three to four years. “We’re very grateful to our existing supply chain, to Samsung, TSMC, Micron and others,” Musk acknowledged at the Terafab event, “but there’s a maximum rate at which they’re comfortable expanding.” Building in-house was, in his framing, not a strategic option, but a necessity.
The space angle is where the announcement becomes genuinely unprecedented. Musk said 80% of Terafab’s compute output would be directed toward space-based orbital AI satellites, arguing that solar irradiance in space is roughly 5x greater than at Earth’s surface, and that heat rejection in vacuum makes thermal scaling viable. This directly feeds the SpaceXAI vision, which is betting that within two to three years, running AI workloads in orbit will be cheaper than doing so on the ground. The satellites, powered by constant solar energy, would effectively turn low Earth orbit into the world’s largest data center.
Will Tesla join the fold? Predicting a triple merger with SpaceX and xAI
Historically, this announcement threads together every major Musk initiative of the past two years: the xAI-SpaceX merger, Tesla’s $2.9 billion solar equipment talks with Chinese suppliers, the 100 GW domestic solar manufacturing push, the Optimus humanoid robot program, and Starship’s development. TERAFAB is the capstone that ties them into a single coherent architecture — chips made on Earth, launched by SpaceX, powered by Tesla solar, run by xAI, and ultimately extended to the Moon.
“I want us to live long enough to see the mass driver on the moon, because that’s going to be incredibly epic,”Musk said during the presentation.
Announcing TERAFAB: the next step towards becoming a galactic civilization https://t.co/IDKey07mJa
— Tesla (@Tesla) March 22, 2026
Elon Musk
SpaceX is quietly becoming the U.S. Military’s only reliable rocket
Space Force drops ULA for SpaceX on GPS launch after Vulcan rocket anomaly investigation halts flights.
The U.S. Space Force announced today it is switching an upcoming GPS III satellite launch from United Launch Alliance’s Vulcan rocket to a SpaceX Falcon 9, a move that is as much a reflection of Vulcan’s mounting problems as it is a validation of SpaceX’s growing dominance in national security space launch. The GPS III Space Vehicle 09, originally contracted to fly on Vulcan this month, will now target a late April liftoff on Falcon 9, marking the fourth consecutive GPS III satellite the Space Force has moved to SpaceX after contracts were originally awarded to ULA.
The immediate trigger is a solid rocket motor anomaly that occurred on February 12 during Vulcan’s USSF-87 mission. Although the payloads reached orbit and ULA declared the mission successful, the company characterized the malfunction as a “significant performance anomaly” and has since paused all military launches on Vulcan pending a root cause investigation.
“With this change, we are answering the call for rapid delivery of advanced GPS capability while the Vulcan anomaly investigation continues,” said Systems Delta 81 Commander Col. Ryan Hiserote. “We are once again demonstrating our team’s flexibility and are fully committed to leverage all options available for responsive and reliable launch for the Nation.”
The broader reality is that SpaceX’s reliability record and launch cadence have made it the path of least resistance for the Pentagon, and bodes well with Elon Musk’s plans to IPO SpaceX sometime this year. Its Falcon 9 is the most flight-proven rocket in history, and the Space Force’s Rapid Response Trailblazer program was specifically designed to enable exactly this kind of provider swap for GPS missions, and effectively building SpaceX’s flexibility into the national security launch architecture by design.
For ULA, the stakes are existential. The company entered 2026 with aspirations of finally turning a corner after years of Vulcan delays, with interim CEO John Elbon pointing to a backlog of over 80 missions as reason for optimism. Meanwhile, SpaceX’s contracts with the Space Force have given it a formal pathway to take on even more national security launches going forward.
The significance of today’s announcement extends beyond one satellite swap. It reinforces that America’s most critical space infrastructure, including GPS, missile warning, and beyond, is increasingly dependent on a single commercial provider.
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