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SpaceX sends “radically redesigned” Starship engine to Texas for hot-fire tests

As of September 2017, subscale Raptor engines had been cumulatively fired for more than 1200 seconds in just 12 months of testing. (SpaceX)

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7 years ago

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SpaceX has shipped one of the first of a group of Starship engines known as Raptor, described last month by CEO Elon Musk as “radically redesigned”. A culmination of more than 24 months of prototype testing, the first flight-worthy Raptor could be ignited for the first time as early as February.

According to Musk, three of these redesigned Raptors will power the first full-scale BFR prototype, a Starship (upper stage) test article meant to conduct relatively low-altitude, low-velocity hop tests over the southern tip of Texas. Those tests could also begin next month, although a debut sometime in March or April is increasingly likely.

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Effectively designed on a blank slate, Raptor began full-scale component-level tests in 2014 at NASA’s Mississippi-based Stennis Space Center, evolving from main injector development to oxygen preburner hot-fires in 2015. Soon after Raptor’s prototype preburner design was validated at Stennis, SpaceX moved testing to its privately-owned and operated facilities in McGregor, Texas, where Raptor static fire testing has remained since.

Just days before CEO Elon Musk was scheduled to reveal SpaceX’s next-generation rocket (BFR, formerly known as the Interplanetary Transport System or ITS) in September 2016, he announced in a tweet that propulsion engineers and technicians had successful hot-fired an integrated Raptor prototype – albeit subscale – for the first time ever. Just 12 months later, Musk once again took to the stage to announce an update to BFR’s design, while also revealing that prototype Raptor engines had already completed more than 1200 seconds (20 minutes) of cumulative hot-fire tests, an extremely aggressive and encouraging rate of progress for such a new engine.

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Although Raptor undoubtedly borrows heavily from much of the same expertise that designed Merlin 1 and operated and improved it for years, that is roughly where the similarities between Raptor and M1D end. M1D, powered by refined kerosene (RP-1) and liquid oxygen, uses a combustion cycle (gas-generator) that is relatively simple and reliable at the cost of engine efficiency, although SpaceX propulsion expertise still managed to give M1D the highest thrust-to-weight ratio of any liquid rocket engine ever flown. Still, measured by ISP (instantaneous specific impulse), M1D’s inefficient kerolox gas-generator cycle ultimately means that the engine simply can’t compete with the performance of engines with more efficient propellants and combustion cycles.

While SpaceX’s Falcon 9 and Heavy rockets – powered by Merlin 1D and Merlin Vacuum – are more than adequate in and around Earth orbit, a far more efficient engine was needed for the company to enable the sort of interplanetary colonization Musk had in mind when he created SpaceX. Raptor was the answer. Ultimately settling on liquid methane and oxygen (methalox) as the propellant and a full-flow staged-combustion (FFSC) cycle, Raptor was designed to be extraordinarily reliable and efficient in order to safely power a spacecraft (BFS/Starship) meant to ferry dozens or hundreds of people to and from Mars.

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An excellent NASASpaceflight article explores the engine’s journey from a blank sheet to integrated static-fire tests and offers a deeper explanation of the technical details.

Raptor enters a new era

For all the extensive and invaluable testing SpaceX has done with a series of prototype Raptor engines, the engines tested were subscale versions with around 30% the thrust of the c. 2016 Raptor and around 40-50% of the updated c. 2017 iteration, producing almost the same amount of thrust as Merlin 1D (914 kN to Raptor’s ~1000 kN). In September 2018, Musk described Raptor as an “approximately…200-ton (~2000 kN) thrust engine” that would eventually operate with a chamber pressure as high as 300 bar (an extraordinary ~4400 psi), requiring at least one of the FFSC engine’s two preburners (used to power separate turbopumps) to operate at a truly terrifying ~810 bar (nearly 12,000 psi).

Conveniently stood beside a Merlin 1D engine also ready for hot-fire acceptance testing, the Raptor engine spotted departing SpaceX’s Hawthorne, CA factory last week was reportedly immense in person, towering over an M1D engine. Raptor also featured a mass of spaghetti-like plumbing (complexity necessary for its advanced combustion cycle), with a significant fraction of the metallic pipes and tubes displaying mirror-like finishes. Most notable was an obvious secondary preburner/turbopump stack and the lack of any exhaust port, whereas M1D relies on a single turbopump and exhausts the gases used to power it. Raptor’s full-flow staged-combustion cycle uses separate oxygen and methane preburners to power separate turbopumps, significantly improving mass flow rate and smoothing out combustion mixing.

 

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Unlike all previous hot-fired Raptors, those shipping now to McGregor, Texas are expected to be the first completed engines with a finalized design, arrived at only after a period of extensive testing and iterative improvement. They also appear to be full-scale, meaning that the test bays dedicated to Raptor will likely need to be upgraded (if they haven’t been already) to support a two- or threefold increase in maximum thrust.

SpaceX’s Starship hopper will need three finalized engines, meaning that the Raptor now in McGregor, Texas may not have been the first to arrive. Nevertheless, the shipment of full-scale hardware is always an extremely encouraging milestone for any advanced technology development program, while also foreshadowing the first imminent static-fires of the “radcally redesigned” rocket engine. With hardware now at the test site before January is out, a February test debut – one month behind a January debut teased by Elon Musk last December – is not out of the question.

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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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Tesla Semi gets strange-but-understandable comparison from Jay Leno

In a recent interview with MotorTrend, legendary comedian and automotive enthusiast Jay Leno shared his impressions after driving Tesla’s long-range Semi truck, offering one of the most vivid descriptions to date:

Published

8 hours ago

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May 9, 2026

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Credit: Jay Leno's Garage

The Tesla Semi recently received a strange-but-understandable comparison from automotive enthusiast and former long-time late-night television show host Jay Leno.

In a recent interview with MotorTrend, legendary comedian and automotive enthusiast Jay Leno shared his impressions after driving Tesla’s long-range Semi truck, offering one of the most vivid descriptions to date:

“It’s like driving an office building.”

The comparison may seem quirky—office buildings evoke images of immobility rather than motion—but it aptly conveys the experience of commanding a massive 23,000-pound Class 8 electric truck that delivers sports-car acceleration.

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Lenotested the production-spec Long Range model, which is rated for up to 500 miles of range. He was visibly impressed by its performance, noting how the enormous vehicle moves with surprising urgency.

“It’s as fast as a Tesla, but it’s like driving an office building,” he remarked. “It’s this huge thing that moves like right now. You go 500 miles. You get 60% charge in 30 minutes. You’re saving on fuel costs. It seems quite good.”

The reaction highlights the cognitive dissonance at the core of the Tesla Semi. Traditional diesel semi-trucks are slow, noisy, and expensive to run. The Semi rewrites the rules with instant torque from its tri-motor electric powertrain, producing up to 800 kW.

Despite its size, the truck feels agile thanks to full electric steering assist, upgraded actuators borrowed from the Cybertruck, and a 48-volt electrical architecture that improves responsiveness and efficiency.

Tesla reports real-world energy consumption below 1.7 kWh per mile for the Long Range version. Megacharger stations can deliver a 60% charge in roughly 30 minutes, making the truck suitable for long-haul operations.

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Additional features include an electric Power Take-Off (ePTO) capable of 25 kW for trailer refrigeration or other equipment, and a driver-focused cab with a central seating position for optimal visibility and a quiet, high-tech interior.

Fleet operators stand to benefit significantly from the economics. Diesel trucks often cost nearly one dollar per mile when including fuel, maintenance, and downtime.

Tesla projects the Semi can reduce operating costs to as low as 15 cents per mile through cheaper electricity, regenerative braking that minimizes brake wear, and reduced service requirements. While early deployments, like Pepsi’s, focused on shorter routes, the 500-mile variant targets cross-country applications.

Obstacles remain. A fully loaded tractor-trailer can reach 80,000 pounds, which reduces real-world range compared to the unloaded test conditions. Building out a nationwide Megacharger network will be essential for broader adoption. The Semi also carries a higher upfront price than conventional diesels, though total cost of ownership and available incentives frequently tip the scales in its favor over time.

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Tesla Semi hauls fresh Cybercab batch as Robotaxi era takes hold

Leno’s “office building” description resonates because it captures the unexpected thrill of piloting something so large yet so capable. As the trucking industry faces pressure to cut emissions and control rising fuel expenses, the Semi offers a compelling alternative that excels in performance, comfort, and efficiency.

Coming from a man who has driven everything from vintage classics to modern hypercars, Leno’s genuine enthusiasm adds weight to the verdict.

The Tesla Semi is emerging as more than an experimental EV—it represents a practical vision for the future of heavy-duty transport where massive rigs accelerate instantly, and the numbers finally make sense. If fleet results continue to validate the claims, the era of diesel dominance could be drawing to a close.

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Tesla expands its mass-market color palette in the U.S.

Delivering a fresh splash of color to its lineup, Tesla is giving U.S. buyers two stunning new blue options that are already turning heads.

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8 hours ago

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May 9, 2026

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Credit: Brand0n | X

Tesla has expanded the color palette it offers on its mass market vehicles in the United States, giving buyers of the Model 3 and Model Y a few additional options than before.

Delivering a fresh splash of color to its lineup, Tesla is giving U.S. buyers two stunning new blue options that are already turning heads. Starting on May 8, the automaker updated its North American configurator to introduce Marine Blue on Model Y Premium trims and Frost Blue exclusively on the Model 3 Performance.

The move replaces the long-running Deep Blue Metallic, a staple for over eight years, and brings previously exclusive shades stateside.

Marine Blue, a deep, rich oceanic hue formerly limited to Europe and Asia-Pacific markets, is now available on Model 3 and Model Y RWD and Long Range AWD Premium variants. Priced at a $1,000 upgrade—standard for Tesla’s premium paints—it delivers a sophisticated, metallic finish that shifts beautifully under light.

Tesla North America highlighted the change directly in an official post, confirming Marine Blue as the new flagship blue for non-Performance models.

Frost Blue, on the other hand, is the real crowd-pleaser for enthusiasts. Previously reserved for the flagship Model S and Model X, this lighter, icy metallic shade is now offered at no extra cost on Model 3 Performance and Model Y Performance trims.

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Performance buyers effectively get a premium color included in the base price, a smart perk that Tesla has extended to higher-end variants across the board. Early in-person sightings and configurator renders show Frost Blue’s cool, modern vibe popping against the cars’ sleek lines, especially with black wheels and red brake calipers.

The timing couldn’t be better. With Tesla pushing refreshed Model 3 and Model Y refreshes amid growing competition, these updates add visual excitement without major redesigns.

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Deep Blue Metallic orders are being transitioned to the new shades, according to customer reports and Tesla communications. In the U.S., Puerto Rico, and Mexico, the options are live now; Canada sees limited Frost Blue availability on the Model 3 Performance.

Tesla’s color strategy continues to evolve, borrowing from higher-end models to refresh mass-market EVs. Now that we bid farewell to the Model S and Model X, some of their colors might be available on the more widely available Model 3 and Model Y.

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Tesla Semi’s official battery capacity leaked by California regulators

A California regulatory filing just confirmed the exact battery size inside each Tesla Semi variant.

Published

2 days ago

on

May 7, 2026

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A regulatory filing published by the California Air Resources Board in April 2026 has put official numbers on what Tesla Semi owners and fleet buyers have long wanted confirmed: the exact battery capacities of both the Long Range and Standard Range Semi truck variants. CARB is California’s independent air quality regulator, and it certifies zero-emission powertrains before they can be sold or operated in the state. When a manufacturer submits a vehicle for certification, the resulting executive order becomes a public document, making it one of the most reliable sources for confirmed production specs on any EV.

The document lists two certified powertrain configurations. The Long Range Semi carries a usable battery capacity of 822 kWh, while the Standard Range version comes in at 548 kWh. Both use lithium-ion NCMA chemistry and share the same peak and steady-state motor output ratings of 800 kW and 525 kW respectively. Cross-referencing Tesla’s published efficiency figure of approximately 1.7 kWh per mile under full load, the 822 kWh pack supports roughly 480 miles of real-world range, which aligns closely with Tesla’s advertised 500-mile figure for the Long Range trim. The 548 kWh Standard Range pack works out to approximately 320 miles, again consistent with Tesla’s stated 325-mile target.

Here is a direct comparison of the two versions based on the CARB filing and published specs:

Tesla Semi Spec Long Range Standard Range
Battery Capacity 822 kWh 548 kWh
Battery Chemistry NCMA Li-Ion NCMA Li-Ion
Peak Motor Power 800 kW 525 kW
Estimated Range ~500 miles ~325 miles
Efficiency ~1.7 kWh/mile ~1.7 kWh/mile
Est. Price ~$290,000 ~$260,000
GVW Rating 82,000 lbs 82,000 lbs

The timing of this certification is not incidental. On April 29, 2026, Semi Programme Director Dan Priestley confirmed on X that high-volume production is now ramping at Tesla’s dedicated 1.7-million-square-foot facility in Sparks, Nevada. A key advantage of the Nevada location is vertical integration: the 4680 battery cells powering the Semi are manufactured in the same complex, eliminating the supply chain bottleneck that had delayed the program for years.

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Tesla’s long-term goal is to reach a production capacity of 50,000 trucks annually at the Nevada factory, which would represent roughly 20 percent of the entire North American Class 8 market. With CARB certification now in hand and the production line running, the regulatory and manufacturing groundwork for that target is in place.

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