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.
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SpaceX is gearing up for the 13th Starship integrated flight test, which is currently scheduled for Thursday, July 16, with the launch window opening up at 6:30 PM E.T. from Starbase in South Texas.
This mission, the second with the V3 Starship and Super Heavy vehicles, builds directly on the foundation of Flight 12 while introducing ambitious new objectives, including the debut deployment of next-generation Starlink V3 satellites.
The rapid iteration between flights underscores SpaceX’s “fail fast, learn faster” philosophy, with engineers addressing specific anomalies from the previous test to push reusability and payload capabilities further.
Starship’s thirteenth flight test is preparing to launch as early as Thursday, July 16 → https://t.co/Rp7VwBzpWx pic.twitter.com/jdpFlQUEpF
— SpaceX (@SpaceX) July 11, 2026
Flight 12 occurred earlier in 2026 and encountered notable challenges that became catalysts for Flight 13’s improvements. Issues included booster course deviations during the flip maneuver after stage separation, reusability problems with Super Heavy’s Raptor engine relights for the boostback burn, and an engine-out event on the Starship upper stage during its propulsion phase.
These hiccups, while they did not prevent overall mission success, highlighted areas needing refinement for more consistent performance and higher safety margins in future operational flights.
Elon Musk called it Epic: The full story of SpaceX’s Starship Flight 12
In response, SpaceX implemented a comprehensive suite of both hardware and software upgrades.
For the booster, engineers developed a more robust stage separation flip sequence to maintain stable orientation and prevent off-course rotation. Hardware modifications have enhanced Raptor re-light reliability during the boostback burn, complemented by updated engine alarms and abort logic tailored for multi-engine operations. On the Starship side, propulsion system changes directly tackle the Flight 12 engine-out scenario, improving redundancy and operational resilience.
Another major focus of SpaceX for Flight 13 was the advancements in the heat shield. New tile designs and attachment mechanisms, including tests of aft flaps and skirts, aim to boost durability.
Load-sensing tiles will measure real-time stresses during atmospheric entry, while white-painted tiles simulate missing ones as imaging targets. Six of the 20 Starlink V3 satellites carried aboard will feature specialized cameras to scan and transmit heat shield imagery back to ground teams, providing critical data for future return-to-launch-site attempts.
The mission profile also includes a higher dynamic pressure ascent to stress-test the thermal protection system and increase payload potential, alongside a planned in-space Raptor engine relight demonstration.
The V3 Starlink satellites themselves mark a leap forward, equipped with laser links, deployable solar arrays, and improved antennas to expand network capacity and speeds.
The company wrote:
“For the first time, Starship will carry V3 Starlink satellites to space, which aim to greatly expand the network’s capacity and user speeds. As part of this initial test, Starship is planned to deploy 20 satellites which will extend solar arrays and antennas and will attempt to connect with ground stations in South Africa and the larger Starlink constellation via high-capacity lasers. Six of the satellites have been modified with a suite of cameras to scan Starship’s heat shield and transmit imagery down to operators to continue testing methods of analyzing Starship’s heat shield readiness for return to launch site on future missions. Several tiles on Starship have been painted white to simulate missing tiles and serve as imaging targets in the test.”
This dual-purpose flight tests both vehicle reliability and satellite tech in one integrated operation.
These iterative changes, catalyzed by Flight 12’s data, position Starship closer to rapid reusability goals essential for ambitious programs like Artemis lunar missions and global Starlink coverage.
As SpaceX continues its aggressive test cadence, Flight 13 exemplifies how targeted engineering responses to real-flight anomalies accelerate progress toward fully operational, high-cadence launches. Success here could mark another milestone in the Starship program for SpaceX.
SpaceX is preparing for the 13th integrated flight test of its Starship system, with a targeted launch as early as Thursday, July 16. The 90-minute launch window opens at 5:45 p.m. CT from Starbase in South Texas.
This comes roughly seven weeks after Flight 12 on May 22, underscoring the company’s accelerating pace in its rapid development campaign. The mission will use the latest Starship and Super Heavy V3 vehicles equipped with Raptor 3 engines. Booster 20 will attempt a controlled boostback burn, followed by a splashdown in the Gulf of Mexico, while Ship 40 will follow a suborbital trajectory.
Starship’s thirteenth flight test is preparing to launch as early as Thursday, July 16 → https://t.co/Rp7VwBzpWx pic.twitter.com/jdpFlQUEpF
— SpaceX (@SpaceX) July 11, 2026
Key objectives for Flight 13 will include demonstrating reliable stage separation, engine performance under various conditions, and controlled reentry.
A major milestone for Flight 13 is the first deployment of 20 next-generation Starlink V3 satellites. These satellites feature advanced laser links for inter-satellite communication, deployable solar arrays, and onboard cameras, six of which will capture imagery of Starship’s heat shield during flight.
Several heat shield tiles on Ship 40 will be painted white to serve as imaging targets, while additional experiments test upgraded tiles on aft flaps, modified attachments on the aft skirt, and load-sensing tiles to measure stresses. The upper stage will also attempt a single Raptor engine relight in space before a targeted splashdown in the Indian Ocean.
These tests build directly on lessons from Flight 12, which introduced the V3 configuration but encountered issues including a booster flip anomaly during boostback and an engine-out event on the ship. Hardware and software modifications on Booster 20 and Ship 40 aim to improve engine relight reliability, startup sequencing, and overall robustness.
Next Starship launch aiming for Thursday https://t.co/SajPPd4pdb
— Elon Musk (@elonmusk) July 12, 2026
The short interval between Flights 12 and 13 highlights SpaceX’s iterative approach. Elon Musk has repeatedly emphasized that Starship launches will become “incredibly common” in the coming years.
The company envisions scaling to rates as high as one launch per hour within 4-5 years, potentially enabling thousands of flights annually. Such cadence is essential for Starship’s goals: establishing orbital refueling for lunar and Mars missions, deploying massive satellite constellations, and making life multiplanetary.
With each flight, Starship edges closer to full reusability and operational maturity. Success on July 16 would mark another step toward routine access to space and the ambitious vision of humanity becoming a spacefaring civilization.
Elon Musk posted a candid admission on his social media platform X on June 9, declaring that he had been “clearly wrong” about Anthropic. The statement marked a notable reversal from his earlier skepticism toward the AI company.
In September, Musk had written, “Winning was never in the set of possible outcomes for Anthropic,” reflecting his view at the time that the startup had lacked the foundation or even the trajectory to succeed in what is an incredibly intense race for advanced artificial intelligence.
Musk’s latest post came amid discussion of Anthropic’s reliance on external compute resources. He praised the company’s progress, stating that Anthropic is “obviously currently the leader in AI” and that “no company has released a model as good as Mythos/Fable,” with expectations of a strong follow-up in Mythos 2.
The tone shifted dramatically from dismissal to acknowledgement of superior performance.
I was clearly wrong about Anthropic. They are obviously currently the leader in AI. No company has released a model as good as Mythos/Fable and they will undoubtedly have Mythos 2 ready soon.
And I would never cut them off in a way that hurt them badly, even as a competitor.…
— Elon Musk (@elonmusk) July 9, 2026
The context of Musk’s comments added significance. Anthropic has been operating under a recent compute deal with SpaceXAI, Musk’s AI infrastructure-focused venture. The pair entered a short-term GPU lease agreement initiated in May, providing Anthropic access to critical computing power for training and deploying its frontier models.
SpaceXAI signs agreement with Anthropic for massive AI supercomputer access
Some observers had speculated that Musk could leverage this dependency to disadvantage a rival. Musk directly addressed the possibility, writing, “I would never cut them off in a way that hurt them badly, even as a competitor. That’s not my style.”
To support his commitment to ethical competition, Musk referenced concrete examples from his other companies. Tesla famously open-sourced its entire portfolio of electric vehicle patents in 2014. The move was designed to accelerate the global adoption of sustainable transportation technology rather than protect proprietary advantages.
Tesla also made its Supercharger network available to competing electric vehicle manufacturers, transforming what could have remained an exclusive charging ecosystem into a shared infrastructure that benefits the broader industry and reduces barriers for EV adoption.
Musk further pointed to SpaceX’s practices, noting that the company launches satellites for competing commercial systems “with no increase in price or use of unfair terms.” He extended the principle to his social platform, observing that “even my worst enemies attack me on this platform,” underscoring preference for open discourse over retaliation.
These examples have illustrated Musk’s long-standing philosophy that long-term technological progress is best served by open competition and infrastructure sharing rather than leveraging market power to stifle rivals. In the fast-evolving AI sector, where compute resources and model capabilities determine leadership, Musk’s stance suggests a willingness to compete on innovation and performance alone.
Musk’s admission arrives as SpaceXAI itself advances its own frontier models while maintaining business relationships across the ecosystem. By publicly correcting his earlier assessment and reaffirming principles of fair play, Musk highlights a model of competition that prioritizes advancement of the field over short-term tactical advantages.
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