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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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Elon Musk explains what happens when AI outsmarts all of us

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Elon Musk told The Economist that artificial intelligence will likely surpass the combined intelligence of every human on Earth within about five years, and that humans may not remain in charge once that happens. In a wide-ranging interview with editor-in-chief Zanny Minton Beddoes, recorded at Giga Texas for the outlet’s Insider series, Musk compared the widening gap between AI and human intelligence to the gap between humans and chimpanzees.

“It’s hard to imagine that the chimpanzee would be in charge,” he said, addressing what happens to human authority once AI moves far beyond us.

Elon Musk reiterates his most optimistic prediction yet with “UHI” forecast

Musk’s timeline stretches out from there. Five years for AI to out-think humanity combined, ten years before humans lose meaningful control, and by 2036, he says, money itself may stop mattering.

Musk notes that if robots and AI produce more goods and services than people could ever consume, currency loses its purpose. He told Beddoes that governments could respond with direct payments, what he called “universal high income,” a term he first used in an X post last August describing a future where “everyone will have the best medical care, food, home, transport and everything else.”

He also floated a more surprising prediction that deflation, and not inflation, would become the bigger economic problem, since expanding the supply of goods and services faster than the money supply grows would push prices down rather than up.

None of this is new territory for Musk, who has spent years describing an “age of abundance” built on Optimus and autonomous vehicles. What’s notable is the timing. The interview landed the same week Tesla shares dropped roughly 19 percent following a second quarter earnings report that beat on revenue but missed badly on profit, and as SpaceX stock continues to slide from its post-IPO peak.

Musk’s own net worth has fallen close to $700 billion since mid-June, according to the Bloomberg Billionaires Index, even as he describes a future where personal wealth stops being the point.
Musk did not dodge the risk side of the equation either. He put the odds of AI contributing to human extinction somewhere in the 10 to 20 percent range, then arrived at what he called his “philosophical conclusion” since the technology cannot realistically be stopped and the arguably better response is to keep building it and hope the outcome leans toward abundance rather than catastrophe. “I’ve gone from exhilaration to terror regarding AI,” he told Beddoes, “even intraday.”

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Tesla adds new ‘Traction Control Modes’ for better handling in any conditions

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Credit: Tesla

Tesla is adding a new “Traction Control Modes” feature to its cars for better handling in any conditions. These features will roll out to the Model 3 and Model Y, the two vehicles in Tesla’s lineup that typically do not have drive modes for various conditions.

Tesla did include this in the Model S and Model X, as well as the Cybertruck.

The new feature will roll out with the 2026 Summer Update, which Tesla announced last week and subsequently started rolling out to some owners today. The Summer Update is the latest iteration of the usual four seasonal releases the company rolls out throughout the year. These releases typically feature some owner-requested features, as well as improvements to things like the Full Self-Driving suite.

Tesla reveals 2026 Summer Update with crazy fixes to Nav and more

This release is no different. Among the changes are improvements to Navigation, new customization options with wraps and how they can be shared and stored, more functionality with the Tesla smartphone app, and new gamification with self-driving.

However, Tesla announced today that it was adding another feature to the Summer Update. Traction Control Modes will now be available with the release

Tesla describes them:

“Choose from three updated Traction Control Modes: Auto for normal driving conditions, Slippery Surface for icy or wet roads, Stuck Assist when stuck in snow, mud, or sand. The mode resets to Auto at the start of each drive. To select, go to Controls > Dynamics > Traction Control Mode.”

The use of these modes will help improve a Tesla’s overall performance in less-than-ideal conditions. Typically, these traction control modes monitor wheel speed through sensors and track engine power to adjust responsiveness in various conditions.

These drive modes are not an ultimate solution to all driving conditions; just because there is a “Stuck Assist,” doesn’t mean your Tesla will dig itself out of a foot-and-a-half trench during a blizzard. It is important to remember that some of these scenarios also require some assistance from the driver. For example, driving in sand requires tires to be aired down significantly to increase traction and control.

However, this will be a welcome addition for those who use the Full Self-Driving suite and might not be convinced of its performance in adverse conditions. Some of us prefer to be in control in rain, snow, or ice, which is totally understandable. However, adjusting the Traction Control Mode while utilizing FSD in snow, rain, or ice could increase confidence and overall experience.

Tesla’s Summer Update is already rolling out to some owners, so it should be making its way to most of the fleet over the next several weeks. The Spring Update rolled out at a very conservative pace, so if you don’t have it by the end of August, don’t be too upset. It might just be Tesla’s method.

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SpaceX wants to catch Starship for launch 14, Elon Musk says

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Credit: SpaceX

Just hours after Starship Flight 13 achieved a successful soft splashdown of its upper stage in the Indian Ocean on July 24, Elon Musk announced an ambitious next step for the company’s next launch of the rocket.

“Unless we discover problems after mission data review, SpaceX will attempt to catch the ship with the tower on [the] next flight,” the SpaceX CEO posted on X on Friday.

That “next flight” is expected to be Flight 14. The plan involves returning the Starship upper stage, commonly called the “ship,” to the Starbase launch tower in Texas and catching it mid-air using the same mechanical “chopsticks” arms that have already proven themselves with the Super Heavy booster.

A successful catch would mark the first time an orbital-class upper stage has been recovered this way, advancing SpaceX’s goal of full and rapid reusability for the entire vehicle.

SpaceX has already demonstrated the tower-catch technique multiple times with Super Heavy. The first successful catch came on Flight 5 in October 2024, when Booster 12 was plucked from the sky by the Mechazilla arms. Subsequent flights, including those involving Boosters 14 and 15, repeated the feat. Several of those recovered boosters were later inspected, refurbished, and flown again, proving the system’s viability for quick turnaround.

Traditional reusable rockets, such as SpaceX’s own Falcon 9 or Blue Origin’s New Shepard, land on legs either on land or droneships. Rocket Lab has recovered its small Electron first stages by helicopter, but those are far lighter vehicles.

SpaceX Starship just nailed something it’s never done before

The China Academy of Launch Vehicle Technology (CALT), a subsidiary of the China Aerospace Science and Technology Corp. (CASC), completed a catch of its booster on July 10. They are the only entity besides SpaceX to attempt and complete the feat.

Flight 13 provided encouraging data. The ship executed a controlled reentry, flipped, and soft-landed intact in the ocean after deploying Starlink satellites, offering the first clear post-splashdown views of an undamaged heat shield. The Super Heavy booster, meanwhile, experienced a harder splashdown in the Gulf of Mexico.

Musk has previously stressed that ship catches would only follow multiple successful soft ocean landings to minimize risk of debris over land.

If Flight 14 succeeds, SpaceX would take a major stride toward routine, rapid reuse of both stages—critical for lowering launch costs and supporting ambitious plans for lunar and Mars missions. For now, teams are reviewing the Flight 13 data. Should everything check out, the next Starship flight could deliver one of the most spectacular recoveries in aerospace history.

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