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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.

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.

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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.

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.

 

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 pitches subscription model for Trump’s Golden Dome

SpaceX pitched a subscription model for Trump’s Golden Dome. Faster deployment, but at the cost of gov control & steady bills.

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(Credit: SpaceX/X)

SpaceX pitched a subscription model for U.S. President Donald Trump’s Golden Dome for America.

SpaceX is a frontrunner to build key components of President Trump’s Golden Dome–formerly known as the Iron Dome. In January, President Trump signed an Executive Order to build an Iron Dome missile defense shield to protect America.

The ambitious project has drawn intense interest from defense startups, including Epirus, Ursa Major, and Armada. Companies with long-standing contracts with the U.S. government are also vying to build Trump’s Golden Dome, like Boeing and Lockheed Martin.

According to six Reuters sources, SpaceX is partnering with Palantir and Anduril on a Golden Dome proposal for the U.S. government.

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The trio is pitching a plan to deploy 400 to 1,000+ satellites for missile detection and tracking, with a separate fleet of 200 attack satellites armed with missiles or lasers to neutralize threats. SpaceX will mainly focus on the sensing satellites, not weaponization.

SpaceX reportedly proposed a subscription service model for Trump’s Golden Dome, where the government pays for access rather than owning the system outright. This approach could bypass some Pentagon procurement protocols, enabling faster deployment. However, it risks locking the government into ongoing costs and reduced control over development and pricing.

A few Pentagon officials are concerned about SpaceX’s subscription model for the Golden Dome because it is a rare approach for major defense programs. U.S. Space Force General Michael Guetlein is exploring whether SpaceX should own and operate its segment or if the U.S. should retain ownership with contractors managing operations.

The Golden Dome’s innovative scope and SpaceX’s subscription model signal a new era for defense contracting. However, Trump’s Golden Dome program is in its early stages, giving the Pentagon time to consider SpaceX’s subscription model proposal. As the Pentagon weighs options, SpaceX’s technical prowess and unconventional approach position it as a key player in Trump’s vision for a robust missile shield.

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Bell Canada takes aim at potential Starlink subsidies

Details of Bell Canada’s anti-Starlink efforts were shared by the Financial Times (FT).

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Credit: SpaceX

Tensions are rising in Canada’s telecommunications landscape as the nation’s leading telecom provider, Bell Canada, seeks to block Elon Musk’s Starlink from accessing potential subsidies.

Details of Bell Canada’s anti-Starlink efforts were shared by the Financial Times (FT).

Bell’s Push to Block Starlink Subsidies

As noted by the FT, Bell Canada and its subsidiary Northwestel are lobbying against potential subsidies that Starlink could receive for providing internet access to the country’s remote northern regions, including the Arctic. In correspondence obtained by the Times, Bell argued that Starlink’s flat pricing proves that it does not require support to operate in Canada’s remote areas. 

A decision about the matter will be announced by the Canadian Radio-television and Telecommunications Commission (CRTC). That being said, the CRTC stated in January that a subsidy would help make “internet services more reliable and affordable for residents of the Far North.”

Starlink’s Defense

SpaceX, Starlink’s parent company, has fired back at Bell, stating that blocking subsidies would harm competition and leave isolated communities such as First Nations groups with fewer, more expensive, and less reliable internet options. 

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While Canada’s two biggest telecommunications groups, Bell and Rogers, still dominate the country’s internet and phone service market, Starlink has been making progress in its efforts to saturate the country’s remote regions. Starlink received official approval to operate in October 2022, and since then, it has grown its customer base to 400,000 active customers as of last year.

Musk’s Empire Under Fire in Canada

The subsidy clash is part of a broader Canadian backlash against Musk’s ventures, which seems to be fueled by his role in the Trump administration. Apart from Bell’s anti-Starlink efforts, Ontario also axed a $100 million Starlink contract. Quebec has noted that it would not be renewing its Starlink subsidy scheme as well. 

Tesla, on the other hand, lost government EV subsidies, with Transport Minister Chrystia Freeland leading the charge. As per Geoff White of the Public Interest Advocacy Center, “We should not be giving one cent of public money to an unaccountable imperialist like Elon Musk.”

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Tesla China’s first Megapack exports are headed for a big battery in Australia

The Tesla Megapack batteries are bound for Queensland’s Western Downs battery project.

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Credit: Tesla Asia/X

A few days ago, Tesla announced that the first Megapack battery units from its Shanghai “Megafactory” were being shipped to Australia.

As per recent reports, the massive grid-scale Tesla batteries are bound for Queensland’s Western Downs battery project.

The Shanghai Megafactory

The Shanghai Megafactory is Tesla’s first battery storage factory outside the United States. Built close to Gigafactory Shanghai, the Shanghai Megafactory is expected to supply Megapack batteries to both China and foreign markets.

The Megapack represents a huge portion of Tesla Energy’s deployments. With 3.9 MWh of energy, Tesla notes that each Megapack is enough to power 3,600 homes for an hour. The Shanghai Megafactory has a capacity to produce 10,000 Megapacks per year to start. 

Mike Snyder, vice president of Tesla, shared his optimism about the Shanghai Megafactory. “Megafactory gives us the ability to scale production and efficiency. We can lower logistics costs as well as product costs, and grow the business to new markets,” he stated.

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Australia Battery Projects

As noted in a report from Renew Economy, the first Megapack shipments from the Shanghai Megafactory will be installed in the second stage of the Western Downs battery project, which is being built by Neoen. The Western Downs battery project involves a 460 MWp solar farm coupled with a 540 MW/1,080 MWh big battery system.

Tesla has also been listed as the battery supplier for the upcoming Calala battery in Tamworth, New South Wales, which will involve 138 Megapack units. The Megapacks for the Calala battery will likely be imported from the Shanghai Megafactory as well.

Data from Rosetta Analytics suggests that Tesla is currently the dominant player in Australia’s energy storage segment, with the company holding over 30% of the market. Tesla has become a notable presence in Australia’s energy sector for years, especially following the company’s buildout of the Hornsdale “big battery,” which was initially comprised of Tesla Powerpacks, in 2017.

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