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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.

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.

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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.

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 loses Model Y program manager in second blow in single day

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7 hours ago

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November 10, 2025

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Credit: Tesla Manufacturing

Tesla has lost its Model Y Program Manager, he announced on LinkedIn, marking the second major departure from the company today.

Emmanuel Lamacchia has been in the role for 4 years and 7 months, responsible for the rollout of the all-electric crossover in several markets.

The Model Y became the best-selling vehicle in the world for two years under Lamacchia’s watch, making this a huge loss for the company. However, it seems the decision was made under Lamacchia’s own initiative.

He confirmed his decision on LinkedIn:

“After 8 incredible years, I’m moving on from Tesla.

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What a journey it’s been… from leading NPI for Model 3 and Model Y variants to becoming the Vehicle Program Manager for Model Y, the best-selling car in the world!

Leading the All-New Model Y launch was the highlight: converting all 4 factories across 3 continents in just 2 weeks. Something that had never been done before in the auto industry.

To the teams who made this possible: you should be incredibly proud. This achievement belongs to you: the engineers, designers, buyers, and associates in Fremont, Shanghai, Berlin, and Austin who turned an impossible timeline into reality.

Grateful to the leaders who trusted me with programs that stretched my capabilities and to the cross-functional partners who showed me that great solutions come from collaboration, not hierarchy.

Tesla taught me how to move fast without breaking things and how to scale from prototypes to millions of units.

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Excited for what’s next. More to share soon.”

It marks the second major program loss for Tesla today, as it also bid farewell to Cybertruck and Model 3 Program Manager Siddhant Awasthi, who said he left voluntarily in “one of the hardest decisions of his life.”

Tesla Cybertruck and Model 3 program manager steps down

Lamacchia was at Tesla for just a shade under eight years, and previously worked for Rolls-Royce for roughly the same amount of time.

After the loss of both Lamacchia and Awasthi today, Tesla has lost a handful of key executives in 2025, including:

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  • David Imai, Director of Design
  • David Lau, VP of Software Engineering
  • Mark Westfall, Head of Mechanical Engineering
  • Prashant Menon, Regional Director in India
  • Vineet Mehta, Head of Battery Architecture
  • Omead Afshar, VP/Head of Sales and Manufacturing in North America
  • Milan Kovac, Head of Optimus Team
  • Jenna Ferrua, Director of HR
  • Troy Jones, VP of Sales, Service, and Delivery
  • Pete Bannon, VP of Hardware Engineering
  • Piero Landolfi, Director of Service
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Tesla prepares to expand Giga Texas with new Optimus production plant

Drone operator Joe Tegtmeyer recognized Tesla construction crews performing ground leveling and clearing efforts at the plant earlier today.

Published

9 hours ago

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November 10, 2025

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Credit: Tesla Optimus | X

Tesla is preparing to expand Gigafactory Texas once again with a brand new facility that will house the eventual manufacturing efforts for Optimus, its humanoid robot.

It is already building some units on a Pilot line at the Fremont Factory in Northern California, but Tesla is planning to build the vast majority of its Optimus project at Gigafactory Texas.

Tesla Optimus gets its latest job, and it’s not in the company’s factories

It will build one million units per year in Fremont, but CEO Elon Musk said the company would build 10 million units every year in Texas at a new building at Giga Texas.

Musk said:

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“I think there could be tens of billions of Optimus robots out there. Um, now obviously it’s very important we pay close attention to safety here. Then a 10 million unit uh per year production line here the I don’t know where we’re going to put the 100 million unit production line. on Mars. Maybe on Mars, I don’t know.”

Evidently, Tesla is ready to begin thinking about the production efforts of Optimus beyond a theoretical standpoint and is starting to prepare for the construction of the manufacturing plant on Giga Texas property.

Drone operator Joe Tegtmeyer recognized Tesla construction crews performing ground leveling and clearing efforts at the plant earlier today:

Production is still slated for 2027, at least at Gigafactory Texas. As previously mentioned, the company is building some units in Fremont for the time being, at least until subsequent versions of the Optimus project advance.

Tesla has done a great job of advancing Optimus forward, but it also has truly grand expectations for the project.

Musk said it could potentially be the biggest product in the history of the planet, as it will revolutionize the way humans perform tasks, probably eliminating monotonous tasks from everyday life.

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Tesla reveals its first Semi customer after launch

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11 hours ago

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November 10, 2025

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Credit: Tesla

Tesla revealed its first customer for the all-electric Semi truck after it launches next year. Who it truly is should not be a surprise.

The Semi is going to finally start deliveries to new companies outside of Tesla’s pilot program starting in 2026. The company has been building a dedicated production facility in Reno, Nevada, that has finally taken shape, but Tesla was evidently not finished with the Semi’s development.

Tesla shares rare peek at Semi factory’s interior

Last week at the Annual Shareholder Meeting, Tesla said it had implemented some new designs into the Semi, helping with efficiency, updating its design, and making it a more suitable vehicle for hauling loads, as the changes also helped increase payload.

Tesla has obtained a lengthy list of companies that have committed to implementing the Semi in their own fleets, hoping to bring their logistics lineups up to date with electric powertrains and autonomous technologies.

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While it is already operating a pilot program with PepsiCo. and Frito-Lay, Tesla will expand to other businesses, primarily using it internally after its launch.

Head of the Semi program at Tesla, Dan Priestley, said the company would be the first user of the vehicle after its launch next year. It has been using it to a certain extent, but the company has not been able to completely abandon gas haulers.

Instead, it will implement the Semi into its fleet for more sustainable vehicle logistics starting next year:

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Tesla has already received orders for the Semi from a variety of large companies, including Walmart, Sysco, Anheuser-Busch, UPS, DHL, J.B. Hunt, among others.

Many analysts see the Tesla Semi as a major contributor to future growth and increasing value within the company, especially from a Wall Street perspective. Some firms say the Semi is one of several near and medium-term contributors to the company increasing its market cap.

Cantor Fitzgerald is just one of those firms, as last week it explicitly listed the Semi as a catalyst.

Analyst Andres Sheppard said, “Overall, we remain bullish on TSLA over the medium to long term. We continue to see meaningful future upside from Energy Storage & Deployment, FSD, Robotaxis/Cybercab, Semis, and Optimus Bots.”

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