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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 Roadster unveiling gets pushed again, but new event details emerge

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Credit: Dan Burkland

Tesla has reportedly pushed the unveiling of the Roadster once again, but there are also evidently new details about the event that the company plans to show off.

The Information reported this morning that Tesla will now unveil, for the second time, the next-generation Roadster in August, a further delay from the multiple timeline that the company had previously stated.

The report has not been confirmed or denied by Tesla at any capacity.

It also states the unveiling event will take place in Texas, the same place that Tesla executives revealed in May would be the place of manufacture for the company’s highly-anticipated supercar, which boasts a top speed of over 250 MPH and 650 miles of range, according to its website.

Tesla is also expected to showcase the SpaceX package, which will be used for faster acceleration and potentially hovering capabilities, at the unveiling event, the report states. Musk has always planned for this to happen, but now it seems it is more realistic than ever

The Roadster has had its unveiling date and manufacturing date pushed back on many occasions. It was set to start production in 2020, but the COVID-19 pandemic crippled supply chain operations, forcing Tesla to push its timeline back considerably.

However, COVID has been over for some time, and Tesla has still not managed to successfully schedule and execute an unveiling event, which is something fans and enthusiasts, as well as those who have put down a $50,000 deposit, have been waiting for.

The vehicle was close to completion last year, but Musk truly wanted Lars Moravy and Franz von Holzhausen to push the limits of the Roadster. In July of last year, Moravy said:

“Roadster is definitely in development. We did talk about it last Sunday night. We are gearing up for a super cool demo. It’s going to be mind-blowing; We showed Elon some cool demos last week of the tech we’ve been working on, and he got a little excited.”

It is important to note two things: Tesla has not confirmed these details, and the company has regularly pushed these dates back. Until Tesla sends out formal invitations with a concrete date, taking any unveiling event reports with a grain of salt is a good idea.

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Tesla Model 3 has a tasty Supercharging incentive, but it’s ending soon

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Credit: Tesla

Tesla is offering a tasty Supercharging incentive on certain Model 3 trims, but the company has officially put a concrete end date on it, so those interested should act fast.

Tesla is offering Free Supercharging for One Year on the Model 3 Premium and Performance trims, the top two offerings of the all-electric sedan. There are three trims of the Model 3 that will have the Free Supercharging offer attached:

  • Premium Rear-Wheel-Drive – $42,490
  • Premium All-Wheel-Drive – $47,490
  • Performance – $54,990

Tesla has now announced that this offer will expire on June 15, giving potential buyers about ten days to take advantage of the incentive.

This could be an additional incentive for car buyers to transition to electric vehicles. Many states are showing gas prices well over $4 per gallon, with the national average currently sitting at $4.22, according to AAA.

Tesla Model 3 wins Edmunds’ Best EV of 2026 award

A free year of Supercharging miles would allow people to charge and travel for free, other than routine maintenance, which is already incredibly cheap compared to a gas car.

At Tesla Superchargers, peak rates, meaning prices between 8 a.m. and 10 p.m., average between $0.45 and $0.60. One year of driving at an average of 12,000 miles would cost between $1,000 and $1,500 at $0.50 per kWh. It’s a pretty good deal.

Supercharging prices have also increased recently:

Tesla has used Free Supercharging to move units in the past, and it’s a great strategy for those who plan to use the car for longer commutes, cross-country drives, or do not have reliable access to home charging.

It should be noted that Tesla recommends that Supercharging be used at a minimum to preserve the life of the battery, as fast-charging is more stressful on the cells.

However, some people might not have an option, so the Free Supercharging incentive could truly be a great reason for many people to charge their cars.

The Supercharging incentive is short-term, and it is pretty rare that Tesla utilizes it, so once this offer is gone, we probably will not see it on the Model 3 for some time.

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Ferrari CEO’s self-driving stance echoes Elon Musk’s — sort of

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Credit: Tesla | Ferrari

Ferrari CEO Benedetto Vigna revealed that the Italian automaker’s future will not involve self-driving, a point that echoes that of Tesla CEO Elon Musk’s — sort of.

You might be thinking, “Are you insane? Musk has been so incredibly hellbent on delivering self-driving vehicles to the public, so much so that he has even hinted that Tesla won’t need the ever-popular and widely-requested Model Y L in the U.S.

However, when it comes to electric supercars with high-performance specs and lofty price tags, Vigna’s stance is exactly what Musk wants for Tesla’s own hypercar project, the Tesla Roadster.

In a new interview with Australian media outlet Drive, Vigna made it clear that Ferrari’s ambitions for the future do not involve autonomy, simply because the company’s cars are not designed for anything but manual, spirited driving.

He said:

“We will not make fully autonomous cars — loud and clear. We want the people to have fun, not the [computer] chips. We want to have a steering wheel and a man or a woman behind the steering wheel. Otherwise, why do you buy a Ferrari?”

This seems to be a reasonable assertion. Ferraris are not made for daily commutes, cross-country road trips, or bumper-to-bumper traffic. They’re made for fast, spirited driving, and many of their buyers will only put a few thousand miles on them throughout their lifetime. True, exciting, fun driving is meant to be done manually.

That is not to say Full Self-Driving or other semi-autonomous suites are not “fun,” but they are meant to take the stress out of driving. They are made for the daily commutes, the rush hour traffic, and the parking lots and garages. It’s made to take the stress out of driving.

Tesla Full Self-Driving attempts 150-mile stress test: the good and the bad

Musk had stated in an interview in early 2026 that the Roadster would also be geared toward fun, manually-controlled driving. On the Moonshots podcast with Peter Diamandis, Musk said about the Roadster:

“This is not a…safety is not the main goal. If you buy a Ferrari, safety is not the number one goal. I say, if safety is your number one goal, do not buy the Roadster…We’ll aspire not to kill anyone in this car. It’ll be the best of the last of the human-driven cars. The best of the last.”

There are cars out there that simply are meant to be driven by humans, and Ferraris and Roadsters are a few of them. Ferrari has no true advantage in developing self-driving; their cars sell at low volumes with high price tags, and their performance specs and engineering are all geared toward spirited driving.

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