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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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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.

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.

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.

 

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.


Check out Teslarati’s newsletters for prompt updates, on-the-ground perspectives, and unique glimpses of SpaceX’s rocket launch and recovery processes!

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 Model Y L gets suspension complaints in over odd issue China

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Credit: @TeslaNewswire/X

The Tesla Model Y L is arguably the most hyped trim of the all-electric crossover, other than the Performance configuration that comes with white-knuckle speed and sports car-level handling.

However, it is not all perfect. Tesla owners in China who took delivery of the Model Y L, denoted with an L to highlight its longer wheelbase, are experiencing what they are referring to as “collapsing” of the rear wheels, as suspension issues appear to be an issue with some of the builds.

The gap between the wheel arch and tire has narrowed to the point that “not even a single finger” could fit, according to a report from Car News China. The failures are not tied to a specific mileage, as one owner said that after just 9,000 kilometers (5,600 miles), they noticed the suspension issue when their car was fully loaded.

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Another one had the issue at 30,000 kilometers (18,640 miles) and noticed that the wheel gap shrank to two fingers, so not as drastic as the person who reported a similar issue at 9,000 km.

Tesla Model Y L is gaining momentum in China’s premium segment

Along with the visual recognition of the issue, others are saying the sagging is causing abnormal wear on the inside of the tires. Extra weight and instant torque already provide additional stress on the tires in electric vehicles during normal operation, so it is no surprise that this is another complaint.

There has been no recall issued by Tesla, and the company has not yet publicly acknowledged the issue.

Some are suggesting that owners use a “finger test” to self-diagnose whether there is an issue with the suspension. There should be four fingers between the tire and the wheel well; anything less than that starts to get dicey.

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Tesla Cybercab event gains steam ahead of massive launch

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Credit: TechOperator | X

Tesla is starting to truly tease and hype its groundbreaking Cybercab event, which takes place tomorrow in Austin, Texas. It will be the first time members of the public will be able to ride in a Cybercab, a vehicle without any manual controls, on public roads.

Tesla has been dropping some hype on X over the past several days, but this morning, the excitement has truly started to build up for the event. Although Cybercab has been unveiled before, this is truly Tesla’s announcement that it is ready to start offering autonomous rides for public passengers in its new ride-hailing-geared vehicle for the first time.

The hype has started with a variety of different social media posts that are a true indication that Tesla is preparing for something big. Teasing so much of the potential of Cybercab, including its ability to truly revolutionize how people hail rides for local travel, is what the big idea for the event entails. The time that many Tesla owners, fans, and investors have been waiting for is potentially here:

The event has remained slim on details. Even invitees are still awaiting true details about what the event will entail, where they’ll go, and what is in store for the evening. This is pretty typical for an event run by Tesla; they keep things under wraps for the most part until the very last minute.

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However, there is no secret about what the real intention of Tesla is for this event: it is going to be a huge reveal party for a vehicle that has no steering wheel and no pedals. It is a truly massive step for the company moving forward.

Speculation persists as to whether this is going to be an event that simply announces that rides will begin with the Cybercab, or it will be something more substantial. Tesla has said in the past that they plan to sell the Cybercab to the general public in what could become a great way to earn passive income by adding it to a more global fleet of Robotaxi-geared vehicles.

Tomorrow, the show begins in Austin, and the Cybercab goes live at some capacity; we just don’t know exactly how quite yet.

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SpaceX tells the FCC that Starship Flight 14 is going to orbit

SpaceX filed with the FCC for Starship Flight 14, its first true orbital launch attempt.

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SpaceX has asked the Federal Communications Commission for permission to fly Starlink terminals during Starship’s fourteenth flight test, and the filing lays out a genuine trip to orbit, something the program has never attempted.

Every Starship flight so far, including Flight 13’s successful splashdown in the Indian Ocean on July 24, has flown a suborbital arc that ends with the ship reentering the atmosphere within the same hour it launches. The FCC paperwork describes a mission profile built around an actual orbital insertion instead.

The payload is the other half of the story. Flight 13 carried 20 production Starlink V3 satellites, but because that mission never reached orbit, the satellites reentered along with the ship rather than joining the constellation, something Teslarati covered in detail after SpaceX released footage shot from one of those satellites as it drifted away from Starship in space. Flight 14 is designed to close that gap. If the orbital insertion holds, the roughly 20 V3 satellites onboard would separate into an operational orbit and could eventually go into service, each one rated for about 1 terabit per second of downlink capacity by SpaceX’s own account.

SpaceX announces new Starbase for ‘thousands of Starship launches annually’

Elon Musk first flagged the orbital attempt during SpaceX’s August 4 earnings call, the company’s first as a public entity following its June IPO under the ticker SPCX. He also floated catching the ship with the Starbase tower on the same flight, an idea he walked back on August 20, saying the catch attempt would more likely come “in a few months,” as Teslarati reported at the time. Flight 14 will instead target a splashdown for the ship in the Indian Ocean, the same recovery method used since Flight 12.

Hardware has been catching up to the ambition. Booster 21 completed a full 33-engine static fire on August 28, and Ship 41 finished its own six-engine test the week before. An airspace briefing circulated to pilots on August 20 listed September 15 as the target date, later than the end of August window Musk mentioned on the earnings call, though SpaceX has not confirmed a launch date publicly and Starship schedules routinely slip while hardware and FAA paperwork line up.

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The FCC filing itself does not guarantee a launch date. It covers communications authority, and not flight readiness, considering SpaceX still needs Ship 41 fully stacked and cleared by the FAA before Flight 14 can fly. But the filing is a real marker of intent and it puts a specific regulatory process behind what had so far only been Musk’s word on the earnings call.

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