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SpaceX’s Starship hopper spotted with trio of dual-bell Raptor engines

Starship revealed a trio of what appear to be new Raptor engines when SpaceX technicians moved the assembly from stand to ground. (NSF - bocachicagal)

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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.

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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.

 

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.

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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.

A trio of Raptors (or Raptor stand-ins) were spotted on Starhopper on Dec 31 by NASASpaceflight user bocachicagal.

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

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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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!

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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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SpaceX IPO could push Elon Musk’s net worth past $1 trillion: Polymarket

The estimates were shared by the official Polymarket Money account on social media platform X.

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Gage Skidmore, CC BY-SA 4.0 , via Wikimedia Commons

Recent projections have outlined how a potential $1.75 trillion SpaceX IPO could generate historic returns for early investors. The projections suggest the offering would not only become the largest IPO in history but could also result in unprecedented windfalls for some of the company’s key investors.

The estimates were shared by the official Polymarket Money account on social media platform X.

As noted in a Polymarket Money analysis, Elon Musk invested $100 million into SpaceX in 2002 and currently owns approximately 42% of the company. At a $1.75 trillion valuation following SpaceX’s potential $1.75 trillion IPO, that stake would be worth roughly $735 billion.

Such a figure would dramatically expand Musk’s net worth. When combined with his holdings in Tesla Inc. and other ventures, a public debut at that level could position him as the world’s first trillionaire, depending on market conditions at the time of listing.

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The Bloomberg Billionaires Index currently lists Elon Musk with a net worth of $666 billion, though a notable portion of this is tied to his TSLA stock. Tesla currently holds a market cap of $1.51 trillion, and Elon Musk’s currently holds about 13% to 15% of the company’s outstanding common stock.

Founders Fund, co-founded by Peter Thiel, invested $20 million in SpaceX in 2008. Polymarket Money estimates the firm owns between 1.5% and 3% of the private space company. At a $1.75 trillion valuation, that range would translate to approximately $26.25 billion to $52.5 billion in value.

That return would represent one of the most significant venture capital outcomes in modern Silicon Valley history, with a growth of 131,150% to 262,400%.

Alphabet Inc., Google’s parent company, invested $900 million into SpaceX in 2015 and is estimated to hold between 6% and 7% of the private space firm. At the projected IPO valuation, that stake could be worth between $105 billion and $122.5 billion. That’s a growth of 11,566% to 14,455%.

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Other major backers highlighted in the post include Fidelity Investments, Baillie Gifford, Valor Equity Partners, Bank of America, and Andreessen Horowitz, each potentially sitting on multibillion-dollar gains.

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SpaceX considering confidential IPO filing this March: report

The filing could pave the way for a June listing at a valuation that may exceed $1.75 trillion.

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Credit: SpaceX/X

SpaceX is reportedly preparing to confidentially file for an initial public offering (IPO) as soon as March. The filing could pave the way for a June listing at a valuation that may exceed $1.75 trillion, potentially making it the largest IPO in history.

The update was initially reported by Bloomberg News, which cited information shared by people reportedly familiar with the matter. 

As per the publication, a confidential filing allows a company to receive regulatory feedback before publicly releasing its financials. Bloomberg’s source, however, noted that the timing of SpaceX’s IPO is still under discussion and plans could change.

SpaceX did not immediately respond to requests for comment.

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A March submission would mark the clearest step yet toward bringing Elon Musk’s private space company into public markets. People familiar with the preparations said the offering could raise as much as $50 billion. That would surpass the $29 billion debut of Saudi Aramco in 2019, currently the largest IPO on record.

Major banks including Goldman Sachs Group Inc., JPMorgan Chase & Co., Morgan Stanley, and Bank of America Corp. are reportedly positioned for senior roles in the transaction. SpaceX is also said to be considering a dual-class structure that would allow insiders, including Musk, to retain enhanced voting control.

Satellite communications provider EchoStar Corp., which holds a stake in SpaceX, reportedly saw its shares rise following news of the potential filing.

At a valuation exceeding $1.75 trillion, SpaceX would immediately have a larger market cap than all but five of the companies traded in the S&P 500 index. That figure would place it ahead of Meta Platforms Inc. and Tesla Inc. by market capitalization, trailing only a small group of mega-cap firms such as Apple Inc. and Microsoft Corp.

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The scale of the proposed valuation reflects SpaceX’s dominance in orbital launch services and its Starlink satellite network, which serves millions of users globally. The company has also outlined long-term expansion plans tied to higher Starship launch cadence, orbital infrastructure, and lunar development initiatives.

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Elon Musk outlines plan for first Starship tower catch attempt

Musk confirmed that Starship V3 Ship 1 (SN1) is headed for ground tests and expressed strong confidence in the updated vehicle design.

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Credit: SpaceX/X

Elon Musk has clarified when SpaceX will first attempt to catch Starship’s upper stage with its launch tower. The CEO’s update provides the clearest teaser yet for the spacecraft’s recovery roadmap.

Musk shared the details in recent posts on X. In his initial post, Musk confirmed that Starship V3 Ship 1 (SN1) is headed for ground tests and expressed strong confidence in the updated vehicle design.

“Starship V3 SN1 headed for ground tests. I am highly confident that the V3 design will achieve full reusability,” Musk wrote.

In a follow-up post, Musk addressed when SpaceX would attempt to catch the upper stage using the launch tower’s robotic arms. 

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“Should note that SpaceX will only try to catch the ship with the tower after two perfect soft landings in the ocean. The risk of the ship breaking up over land needs to be very low,” Musk clarified. 

His remarks suggest that SpaceX is deliberately reducing risk before attempting a tower catch of Starship’s upper stage. Such a milestone would mark a major step towards the full reuse of the Starship system.

SpaceX is currently targeting the first Starship V3 flight of 2026 this coming March. The spacecraft’s V3 iteration is widely viewed as a key milestone in SpaceX’s long-term strategy to make Starship fully reusable. 

Starship V3 features a number of key upgrades over its previous iterations. The vehicle is equipped with SpaceX’s Raptor V3 engines, which are designed to deliver significantly higher thrust than earlier versions while reducing cost and weight. 

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The V3 design is also expected to be optimized for manufacturability, a critical step if SpaceX intends to scale the spacecraft’s production toward frequent launches for Starlink, lunar missions, and eventually Mars. 

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