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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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SpaceX’s newest logo confirms everything about what it’s become

SpaceX officially absorbed xAI under the SpaceXAI brand, completing the largest private merger in history.

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SpaceX made its corporate transformation official in May 2026 when Elon Musk posted on X that xAI would cease to exist as a standalone company. “xAI will be dissolved as a separate company, so it will just be SpaceXAI, the AI products from SpaceX,” he wrote.

A new SpaceXAI logo was announced today, visually embedding the xAI letters inside the SpaceX identity, which can be seen as a deliberate design choice that signals the merger is not a partnership but a full absorption and XAi a core function of the same company. The same way Starlink is not a separate brand but a SpaceX product. The announcement closed the loop on a process that began February 2, 2026, when SpaceX acquired xAI in the largest private merger in history, valued at $1.25 trillion. SpaceX at $1 trillion and xAI at $250 billion.


The reason SpaceX bought xAI was stated plainly by Musk at the time of the deal: to build orbital data centers. SpaceX had simultaneously filed with the FCC to launch up to one million satellites designed to function as AI compute nodes in low Earth orbit, escaping what Musk described as the energy constraints limiting AI development on Earth.

xAI provided the AI software stack, with Grok, the X platform, and the Colossus supercomputer infrastructure in Memphis with over 220,000 NVIDIA GPUs, while SpaceX provided the rockets, Starlink, and the capital base to fund it. The two companies needed each other. xAI was burning $2.5 billion in losses on $250 million in revenue. SpaceX was generating an estimated $8 billion in profit on $15 billion in revenue and needed an AI narrative to command the valuation it was targeting for its IPO.

SpaceXAI just launched into your kitchen with their new app

What SpaceX has done, regardless of how the orbital AI vision ultimately plays out, is walk into a public market as something no company has been before: a rocket manufacturer, satellite internet provider, AI software company, social media platform, and supercomputer operator under one ticker. Whether that combination is worth $2 trillion depends entirely on which of those businesses you believe in most.

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Tesla flexes how it will help the blind with Cybercab

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Credit: Tesla

Tesla brought its innovative Cybercab robotaxi to the National Federation of the Blind (NFB) Annual Convention in Austin, Texas, on July 3 at the JW Marriott Austin.

The hands-on demonstration highlighted the vehicle’s thoughtful design for blind and visually impaired users, underscoring Tesla’s commitment to inclusive autonomous mobility. Attendees, many using white canes or accompanied by service dogs, experienced the steering-wheel-free Cybercab firsthand.

The showcase emphasized practical features tailored to the needs of the blind community. Braille lettering appears on physical controls, including door releases and emergency buttons, allowing users to navigate interfaces independently through touch. Generous interior space accommodates service animals and assistive devices such as canes, guide dogs, or mobility aids without compromising comfort.

Wheelchair-height seating facilitates easier transfers for users with additional mobility challenges. Photos from the event captured blind attendees approaching the vehicle confidently, service dogs relaxing inside, and hands exploring Braille-equipped handles.

Tesla Robotaxi’s official account detailed these elements, noting the Cybercab’s focus on accessibility, especially noting the Braille lettering and additional space for service animals.

How Tesla Will Transform Mobility for the Blind

Autonomous vehicles like the Cybercab promise revolutionary independence for the roughly 2.2 million visually impaired Americans. Traditional barriers—reliance on sighted drivers, costly paratransit, or limited public transit—often restrict spontaneous travel. Tesla Full Self-Driving aims to eliminate the need for a human operator, enabling on-demand, door-to-door rides via simple app hailing with voice guidance.

Users gain freedom to work, socialize, shop, or attend events anytime without scheduling hassles or safety concerns. This reduces isolation, boosts employment opportunities, and enhances quality of life, turning mobility from a dependency into true personal autonomy.

The NFB demonstration not only gathered valuable feedback but also generated excitement about a future where technology levels the playing field. By prioritizing inclusive design, Tesla advances a vision of transportation that serves everyone, potentially reshaping daily life for blind individuals and setting a standard for the autonomous industry.

As Cybercab deployment scales, these accessibility innovations could mark a significant step toward equitable mobility.

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Investor's Corner

Tesla challenges startups to score a gig inside its most advanced European factory

Tesla is challenging startups to bring their best battery tech directly to Gigafactory Berlin.

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Tesla has issued an open challenge to startups across Europe, inviting them to bring their best battery technology directly to the floor of Gigafactory Berlin. The program, called the JUNI x Tesla Battery Cell Giga Challenge, opened applications this month with a deadline of July 24, 2026, and is targeting startups with solutions that can make battery cell manufacturing faster, cheaper, safer, and more scalable at an industrial level.

The timing of the challenge is directly tied to Tesla’s most aggressive European battery investment yet. On May 12, 2026, Giga Berlin plant manager André Thierig announced a $250 million investment to scale the factory’s annual 4680 cell production capacity from 8 GWh to 18 GWh, more than doubling the previous target set just months earlier in December 2025. Thierig confirmed the expansion on X, saying the investment “will enable 18 GWh of annual 4680 cell production and create more than 1,500 new jobs.” Combined with a previously announced battery investment at the Grunheide site now approaches $1.2 billion.


The challenge is looking specifically for startups with proven solutions across five categories: materials, equipment, operations, automation, and artificial intelligence. Applications are screened directly by Tesla’s cell manufacturing team in Grunheide, and the strongest submissions move through technical discussions, a pitch day in front of Tesla stakeholders, and potentially a paid pilot project with the cell team. Tesla is not looking for ideas at concept stage. The program requires applicants to demonstrate working prototypes, test data, or prior pilots before being considered.

The historical context matters here. Elon Musk first announced plans for what he called the world’s largest battery cell production facility alongside the Giga Berlin car factory back in 2020, targeting up to 250 GWh of annual capacity. Those plans were shelved in 2022 when Tesla shifted its battery investment focus to the United States to take advantage of Inflation Reduction Act incentives. The revival of cell production at Giga Berlin, now backed by over $1 billion in committed capital, represents a return to an ambition that was set aside for three years. As Teslarati has reported, the 4680 format is central to Tesla’s long-term cost reduction strategy across vehicles, energy storage, including the Tesla Semi and Cybercab.

By opening the challenge to outside startups, Tesla is acknowledging that reaching 18 GWh at Grunheide will require technology it does not currently have in-house, and it is willing to pay for the right solutions. For a startup in the battery supply chain, a paid pilot with Tesla’s European cell team is as close to a direct commercial path as the industry offers.

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