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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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6 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 offers interesting promo to future ride-hailing rival’s drivers

Lyft drivers will get $1,000 in vehicle credits if they complete 100 rides by the cutoff date for the promo.

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5 hours ago

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May 16, 2025

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(Credit: Tesla)

Tesla has offered an interesting promotion for its vehicles to the drivers of one of its future ride-hailing rivals as it continues to work toward the launch of its autonomous Robotaxi platform.

This morning, Tesla launched a $1,000 off promotion to Lyft drivers who plan to utilize one of the company’s EVs for ride-hailing purposes. The promo applies to all five Tesla models: the Model S, Model 3, Model X, Model Y, and Cybertruck.

It is not offered at the point of sale. Instead, to ensure the vehicle is properly utilized for ride-hailing purposes and to prove the discount, Tesla will offer $1,000 in vehicle credits to the Lyft driver after they complete 100 trips on or before July 13, 2025. Delivery must be taken by June 30.

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It is an interesting move by Tesla because Lyft, along with Uber, will become a rival in the coming years as the companies continue to develop driverless ride-hailing platforms of their own. Lyft has partnered with May Mobility and Mobileye to develop driverless, fully autonomous vehicles purpose-built for ride-hailing.

Tesla plans to launch its Robotaxi platform next month in Austin, Texas.

Tesla hints at June 1 launch of Robotaxi platform in Austin

Meanwhile, Lyft’s plans are more down the road. Earlier this year, the company said it would launch autonomous rides sometime next year.

For now, the move seems to be just another way Tesla is incentivizing consumers to buy one of their vehicles. Earlier this week, it also launched another $1,000 off promo for teachers, students, retirees, active-duty members, their spouses, and surviving spouses.

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Previously, Tesla only offered that discount to military members.

It is unclear why Tesla would be offering these discounts, but it could be more of a thank you or an act of recognition, more than anything. If it were a measure that was taken to increase demand, it would be substantially more of a discount. For example, when Tesla was trying to rid its inventory of legacy Model Y units as the new, updated vehicle was set to be released, discounts were over $5,000.

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Tesla Giga Berlin seems to be using FSD Unsupervised to move Model Y units

Tesla may be doing something quite special in the Giga Berlin-Brandenburg complex.

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6 hours ago

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May 16, 2025

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Tesla FSD Unsupervised Giga Texas

Tesla may be doing something quite special in the Giga Berlin-Brandenburg complex. Based on observations from a recent drone flyover of the site, it appears that Tesla may also be using FSD Unsupervised to move freshly produced Model Y vehicles to the factory’s staging area.

New Drone Footage

Recent footage of the Giga Berlin complex from longtime Tesla watcher Tobias Lindh included several interesting updates around the Model Y factory. These include a new warehouse that is currently being built, as well as a tunnel is currently being constructed. More interestingly, the drone operator observed that some cars now seem to be moving to Giga Berlin’s distribution area without human drivers.

If the drone operator’s observations prove accurate, it would be quite an impressive accomplishment for Tesla. FSD Unsupervised, after all, has only been confirmed in vehicles that are produced at the Fremont Factory and Gigafactory Texas.

https://twitter.com/NicklasNilsso14/status/1922799362511376892

Potential Next Steps

If Giga Berlin is now using FSD Unsupervised to transport some Model Y units from the factory building to the site’s staging area, it might only be a matter of time before Tesla also implements a similar system for Gigafactory Shanghai. The Shanghai-based Tesla plant, after all, is the company’s largest factory by volume, and it also serves as a primary vehicle export hub. FSD Unsupervised could then pave the way for Giga Shanghai to operate in an even more optimal manner. 

FSD Unsupervised is the cornerstone of Tesla’s robotaxi business, which is expected to start rolling out in Austin, Texas, next month. Previous reports have suggested that Tesla is pushing hard in its preparations to roll out its robotaxi service this June. Tesla has reportedly even worked and trained with Austin’s first responders from the fire and police departments as part of its robotaxi service preparations.

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Check out a recent flyover of the Tesla Giga Berlin complex in the video below.

https://www.youtube.com/watch?v=p9RFgOiFiU0
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Investor's Corner

Tesla welcomes Chipotle President Jack Hartung to its Board of Directors

Tesla announced the addition of its new director in a post on social media platform X.

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6 hours ago

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May 16, 2025

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Credit: @ArthurFromX/X

Tesla has welcomed Chipotle president Jack Hartung to its Board of Directors. Hartung will officially start his tenure at the electric vehicle maker on June 1, 2025.

Tesla announced the addition of its new director in a post on social media platform X.

Jack Hartung’s Role

With Hartung’s addition, the Tesla Board will now have nine members. It’s been a while since the company added a new director. Prior to Hartung, the last addition to the Tesla Board was Airbnb co-founder Joe Gebbia back in 2022. As noted in a Reuters report, Hartung will serve on the Tesla Board’s audit committee. He will also retire from his position as president and chief strategy officer at Chipotle, and transition into a senior advisor’s role at the restaurant chain, next month.

Hartung has had a long career in the Mexican grill, joining Chipotle in 2002. He held several positions in the company, most recently serving as Chipotle’s President and Chief Strategy Officer. Tesla highlighted Hartung’s accomplishments in a post on its official account on X.

“Over the past 20+ years under Jack’s financial leadership, Chipotle has seen significant growth with over 3,700 restaurants today across the United States, Canada, the United Kingdom, France, Germany, Kuwait and the United Arab Emirates. Jack was named ‘CFO of the Year’ by Orange County Business Journal and Best CFO in the restaurant category by Institutional Investor,” Tesla wrote in its post on X.

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Tesla Board and Musk

Tesla is a controversial company with a controversial CEO, so it is no surprise that the Board of Directors tend to get flak as well. Two weeks ago, for example, Tesla Board Chair Robyn Denholm slammed The Wall Street Journal for publishing an article alleging that company directors had considered a search for a potential successor to Elon Musk. Denholm herself has also been criticized for offloading her TSLA shares.

More recently, news emerged suggesting that the Tesla Board of Directors had formed a special committee aimed at exploring a new pay package for CEO Elon Musk. The committee is reportedly comprised of Tesla board Chair Robyn Denholm and independent director Kathleen Wilson-Thompson, and they would be exploring alternative compensation methods for Musk’s contributions to the company.

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