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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.

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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) could be approved in the Netherlands next month: Musk

Musk shared the update during a recent interview at Giga Berlin.

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Credit: Tesla

Tesla CEO Elon Musk shared that Full Self-Driving (FSD) could receive regulatory approval in the Netherlands as soon as March 20, potentially marking a major step forward for Tesla’s advanced driver-assistance rollout in Europe.

Musk shared the update during a recent interview at Giga Berlin, noting that the date was provided by local authorities.

“Tesla has the most advanced real-world AI, and hopefully, it will be approved soon in Europe. We’re told by the authorities that March 20th, it’ll be approved in the Netherlands,’ what I was told,” Musk stated

“Hopefully, that date remains the same. But I think people in Europe are going to be pretty blown away by how good the Tesla car AI is in being able to drive.”

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Tesla’s FSD system relies on vision-based neural networks trained on real-world driving data, allowing vehicles to navigate using cameras and AI rather than traditional sensor-heavy solutions. 

The performance of FSD Supervised has so far been impressive. As per Tesla’s safety report, Full Self-Driving Supervised has already traveled 8.3 billion miles. So far, vehicles operating with FSD Supervised engaged recorded one major collision every 5,300,676 miles. 

In comparison, Teslas driven manually with Active Safety systems recorded one major collision every 2,175,763 miles, while Teslas driven manually without Active Safety recorded one major collision every 855,132 miles. The U.S. average during the same period was one major collision every 660,164 miles.

If approval is granted on March 20, the Netherlands could become the first European market to greenlight Tesla’s latest supervised FSD (Supervised) software under updated regulatory frameworks. Tesla has been working to secure expanded FSD access across Europe, where regulatory standards differ significantly from those in the United States. Approval in the Netherlands would likely serve as a foundation for broader EU adoption, though additional country-level clearances may still be required.

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Elon Musk estimates Tesla Semi could reach Europe next year

“We’ve got the Tesla Semi coming out, the heavy truck, and that’ll be going to Europe hopefully next year,” Musk said.

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Credit: Tesla

Tesla is preparing to expand its all-electric Semi truck program to Europe, with CEO Elon Musk indicating that the Class 8 vehicle could arrive in the region 2027.

Musk shared his update during an interview about Giga Berlin with plant manager André Thierig, which was posted on X by the official Tesla Manufacturing account.

“We’ve got the Tesla Semi coming out, the heavy truck, and that’ll be going to Europe hopefully next year,” he said.

Tesla has already begun limited production and customer deployments of the Tesla Semi in the United States, with the company working to scale output through the Semi factory near Giga Nevada. Considering Musk’s comments, it appears that a European rollout would be the next phase of the vehicle’s expansion beyond North America.

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Musk’s use of the word “hopefully” leaves room for flexibility, but the remark signals that Europe is next in Tesla’s commercial expansion plans.

Musk has consistently argued that electrification should extend beyond passenger vehicles. During the same interview, he reiterated his view that “all ground transport should be electric,” adding that ships, and eventually aircraft, would follow.

The Semi plays a central role in that strategy. Heavy-duty freight remains one of the most emissions-intensive segments of road transport, and European regulators have increasingly pushed for lower-emission commercial fleets. 

Tesla recently refreshed the Semi lineup on its official website, listing two variants: Standard and Long Range. The Standard trim offers up to 325 miles of range with an energy consumption rating of 1.7 kWh per mile, while the Long Range version provides up to 500 miles, which should be more than ample for European routes.

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Tesla Cybercab coming next to Giga Berlin, Optimus possibly after

“From a next major product standpoint, I think most likely is the Tesla Cybercab,” Musk said.

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Credit: Cybercab

Tesla could add the Cybercab and Optimus humanoid robot to the production lineup at Giga Berlin, as per recent comments from CEO Elon Musk. 

During a recent interview with Giga Berlin plant manager André Thierig, Musk identified the Cybercab as the most likely next major product for the German factory, with Optimus potentially following after.

“From a next major product standpoint, I think most likely is the Tesla Cybercab,” Musk said. He added that there are also “possibilities of Tesla Optimus” being produced in the facility.

Tesla has already begun production of the Cybercab in Giga Texas, with volume production expected to ramp this year. Based on Musk’s comments, it appears that if conditions align in Europe, Giga Berlin could eventually join that effort.

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The CEO’s comments about Optimus coming to Gigafactory Berlin are quite unsurprising too considering that Musk has mentioned in the past that the humanoid robot will likely be Tesla’s highest volume product in the long run. 

Giga Berlin will likely be able to produce mass volumes of Optimus, as the Model S and Model X lines being converted to an Optimus line in the Fremont Factory are already expected to produce 1 million units of the humanoid robot annually. 

Apart from his comments about the Cybercab and Optimus, Elon Musk also confirmed that Giga Berlin has started ramping battery cell production and will continue expanding Model Y output, particularly as supervised Full Self-Driving (FSD) gains regulatory approvals in Europe.

Taken together, the remarks suggest Berlin’s role could evolve beyond vehicle assembly into a broader multi-product manufacturing hub, not just a regional Model Y plant.

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