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SpaceX’s Starship Raptor Vacuum engine plans laid out by CEO Elon Musk

A 2016 render of Raptor Vacuum. Much has changed about the engine's design in the three years since, but SpaceX is still pursuing a vacuum variant. (SpaceX)

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Elon Musk says that SpaceX Starship engine upgrades are on track to begin static fire tests of a Raptor Vacuum variant as few as a “couple months” from now.

Designed to enable more efficient performance in thin atmosphere or vacuum, Musk admitted that the first version(s) of Raptor Vacuum (RVac) will likely be a compromise between efficiency and speed of development. Nevertheless, the faster SpaceX can prepare Raptor Vacuum for flight, the easier it will be for Starship to begin serious (sub)orbital flight tests.

As it turns out, SpaceX’s first and only official render of Raptor – published in September 2016 – showed the engine’s vacuum-optimized variant. In the years since, CEO Elon Musk has vacillated between keeping the vacuum engines as a central Starship feature and simply replacing them with regular sea level Raptors to expedite the spacecraft’s debut. The 2016 and 2017 vehicles featured a mixture of vacuum and sea-level engines, whereas Musk revealed a vehicle with sea-level engines only in 2018.

Known as the Interplanetary Transport System in 2016, the ship featured six vacuum Raptors and 3 SL engines. (SpaceX)
In 2017, Big Falcon Spaceship shrunk and changed to 4 x RVac and 3x x Raptor SL engines. (SpaceX)
In 2018, Musk decided to sidestep vacuum engines entirely, moving to 7 SL Raptors. (SpaceX)

Perhaps less than a month after Musk’s September 2018 presentation, the SpaceX CEO made the decision to radically redesign the vehicle – newly christened Starship and Super Heavy – by moving from a carbon composite aerostructure to stainless steel. At first, the seven SL Raptors remained a part of the design, but Musk took to Twitter in 2019 to indicate that SpaceX had changed gears again and had reprioritized Raptor Vacuum development.

This came as a bit of surprise and it should go without saying that there’s a significant chance that Musk/SpaceX will oscillate in the opposite direction once again before Raptor Vacuum is actually ready for flight. This time, though, Musk has sketched out a development schedule and strategy that suggests SpaceX is much more serious this time.

Most notably, Musk claims that the first Raptor Vacuum prototype could be ready for static fire testing just a “couple months” from now, an immensely ambitious schedule for any large liquid rocket engine development program. Nevertheless, Musk did indicate that the “V1.0” Raptor Vacuum design would be significantly compromised and “suboptimal”, an intentional decision to prioritize the engine’s “speed of development”.

Even then, Musk believes that the first variant – featuring a shortened bell nozzle – could still be up to 12% more efficient than sea level Raptors and thus already 70-80% of the way to the physical limit of methane-oxygen rocket efficiency.

A sea-level Raptor engine is static-fired at SpaceX’s McGregor, TX test facilities. (SpaceX)

On a positive note, shrinking V1.0 Raptor Vacuum’s nozzle a bit from its nominal length will likely mean that SpaceX can static fire fully-integrated engines at its McGregor, TX test facilities, critical for speedy development. If not, the company has experience with alternatives through Merlin Vacuum, which can only be tested on the ground with its lengthy nozzle detached. This method just makes it dramatically harder to optimize a vacuum nozzle design, as full-scale, flight-like testing is nearly impossible if a given vacuum engine can’t be tested on the ground with said nozzle installed.

Vacuum engines need such large and unwieldy nozzles in order to make them as efficient as possible. In a very simplistic sense, a rocket engine nozzle directs the flow of superheated, ultrafast gases in order to squeeze as much momentum transfer as possible out of available propellant. The lower the pressure of the surrounding atmosphere is, the more those gases will expand immediately after leaving the nozzle – giant vacuum nozzles simply try to harness the additional momentum available from that extra expansion. This is why rocket exhausts appear to spread and thin out as launch vehicles reach higher and higher altitudes.

A Falcon 9 upper stage’s vacuum nozzle glows white hot during an orbital MVac burn. (SpaceX)

In this sense, the perfect theoretical vacuum nozzle is quite literally infinitely long. The job of vacuum rocket engineers is to find the perfect balance between that impractical theoretical perfection and the limits of real-world materials and dynamics. In theory, SpaceX’s sea-level Raptor engines have already been designed to operate in vacuum conditions, while the engine’s closed-cycle design and regeneratively (i.e. propellant) cooled nozzle should apply well to a vacuum design.

If SpaceX is lucky, there will be few roadblocks in the way of simply lengthening a SL Raptor-style nozzle and calling it a day, in which case it would be impressive but not all that surprising if SpaceX is actually able to begin RVac testing before the end of 2019. Once a rough V1.0 engine is in place, the process of optimizing efficiency can be done slowly and methodically, all while exploiting an unprecedented wealth of data from flight and orbit-tested Raptor Vacuum engines.

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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 FSD Supervised ride-alongs in Europe begin in Italy, France, and Germany

The program allows the public to hop in as a non-driving observer to witness FSD navigate urban streets firsthand.

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Credit: Tesla

Tesla has kicked off passenger ride-alongs for Full Self-Driving (Supervised) in Italy, France and Germany. The program allows the public to hop in as a non-driving observer to witness FSD navigate urban streets firsthand. 

The program, detailed on Tesla’s event pages, arrives ahead of a potential early 2026 Dutch regulatory approval that could unlock a potential EU-wide rollout for FSD.

Hands-Off Demos

Tesla’s ride-along invites participants to “ride along in the passenger seat to experience how it handles real-world traffic & the most stressful parts of daily driving, making the roads safer for all,” as per the company’s announcement on X through its official Tesla Europe & Middle East account. 

Sign-ups via localized pages offer free slots through December, with Tesla teams piloting vehicles through city streets, roundabouts and highways.

“Be one of the first to experience Full Self-Driving (Supervised) from the passenger seat. Our team will take you along as a passenger and show you how Full Self-Driving (Supervised) works under real-world road conditions,” Tesla wrote. “Discover how it reacts to live traffic and masters the most stressful parts of driving to make the roads safer for you and others. Come join us to learn how we are moving closer to a fully autonomous future.”

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Building trust towards an FSD Unsupervised rollout

Tesla’s FSD (Supervised) ride-alongs could be an effective tool to build trust and get regular car buyers and commuters used to the idea of vehicles driving themselves. By seating riders shotgun, Tesla could provide participants with a front row seat to the bleeding edge of consumer-grade driverless systems.

FSD (Supervised) has already been rolled out to several countries, such as the United States, Canada, Australia, New Zealand, and partially in China. So far, FSD (Supervised) has been received positively by drivers, as it really makes driving tasks and long trips significantly easier and more pleasant.

FSD is a key safety feature as well, which became all too evident when a Tesla driving on FSD was hit by what seemed to be a meteorite in Australia. The vehicle moved safely despite the impact, though the same would likely not be true had the car been driven manually.

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Swedish union rep pissed that Tesla is working around a postal blockade they started

Tesla Sweden is now using dozens of private residences as a way to obtain license plates for its vehicles.

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Andrzej Otrębski, CC BY-SA 4.0 , via Wikimedia Commons

Two years into their postal blockade, Swedish unions are outraged that Tesla is still able to provide its customers’ vehicles with valid plates through various clever workarounds. 

Seko chairman Gabriella Lavecchia called it “embarrassing” that the world’s largest EV maker, owned by CEO Elon Musk, refuses to simply roll over and accept the unions’ demands.

Unions shocked Tesla won’t just roll over and surrender

The postal unions’ blockade began in November 2023 when Seko and IF Metall-linked unions stopped all mail to Tesla sites to force a collective agreement. License plates for Tesla vehicles instantly became the perfect pressure point, as noted in a Dagens Arbete report.

Tesla responded by implementing initiatives to work around the blockades. A recent investigation from Arbetet revealed that Tesla Sweden is now using dozens of private residences, including one employee’s parents’ house in Trångsund and a customer-relations staffer’s home in Vårby, as a way to obtain license plates for its vehicles.

Seko chairman Gabriella Lavecchia is not pleased that Tesla Sweden is working around the unions’ efforts yet again. “It is embarrassing that one of the world’s largest car companies, owned by one of the world’s richest people, has sunk this low,” she told the outlet. “Unfortunately, it is completely frivolous that such a large company conducts business in this way.”

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Two years on and plates are still being received

The Swedish Transport Agency has confirmed Tesla is still using several different workarounds to overcome the unions’ blockades.

As noted by DA, Tesla Sweden previously used different addresses to receive its license plates. At one point, the electric vehicle maker used addresses for car care shops. Tesla Sweden reportedly used this strategy in Östermalm in Stockholm, as well as in Norrköping and Gothenburg.

Another strategy that Tesla Sweden reportedly implemented involved replacement plates being ordered by private individuals when vehicles change hands from Tesla to car buyers. There have also been cases where the police have reportedly issued temporary plates to Tesla vehicles.

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Czech Deputy excited for Tesla FSD, hints at Transport Committee review

The ANO party lawmaker shared his thoughts about FSD in a post on social media platform X.

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Credit: @BLKMDL3/X

Martin Kolovratník, a Czech Republic Chamber of Deputies member, has expressed his excitement for Tesla’s Full Self-Driving (FSD) after an apparent constituent called for a quick approval for the advanced safety system.

The ANO party lawmaker, who drives both diesel and EV, shared his thoughts about the matter in a post on social media platform X.

The official’s initial statements

Kolovratník kicked off the exchange with a post outlining his coalition’s efforts to scrap highway toll exemptions for electric vehicles and plug-ins starting in 2027. 

“Times have changed. Electric vehicles are no longer a fringe technology, but a full-fledged part of operations. And if someone uses the highway network, they should follow the same rules as everyone else. That’s the basis of fairness,” he wrote.

He emphasized equity over ideology, noting his personal mix of diesel and electric driving. “For this reason, there is no reason to continue favoring one technology at the expense of another… It’s not about ideology, it’s about equal conditions. That’s why we clearly agreed within the new coalition: the exemption for electric vehicles and plug-ins will end in 2027. The decision is predictable, understandable, and economically sound.”

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Tesla FSD enthusiasm

The conversation pivoted to Tesla’s FSD when X user @robotinreallife, who seems to be one of the official’s constituents, replied that other matters are more important than ending highway exemptions for EVs. 

“I’m happy to pay for the highway, but I have a question about a much more fundamental matter: The Netherlands will approve the operation of Tesla FSD in February 26, a technology that has been proven to reduce accidents. The Czech Republic has the option to immediately recognize this certification. Do you plan to support this step so that we don’t unnecessarily delay?” the X user asked. 

Kolovratník responded promptly, sharing his own excitement for the upcoming rollout of FSD. “I know about it. I like it and it seems interesting to me. Once we set up the committees and subcommittees, we’ll open it right away in that transport one. Thanks for the tip, I’ll deliver the report,” the official noted in his reply on X. 

Kolovratník’s nod to FSD hints at the system’s potentially smooth rollout to Czechia in the coming year. With the Netherlands possibly greenlighting FSD (Supervised) in early 2026, Kolovratník’s commitment could accelerate cross-border certification, boosting FSD’s foray into Europe by a notable margin.

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