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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 looks to expand into new Asian market, strengthening presence

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Credit: Tesla Asia | X

Tesla is looking to expand into a new Asian market, strengthening its presence in a region that has been bullish on electric vehicles as a whole.

Tesla officially filed to establish a subsidiary of its business in Vietnam, a report from Reuters suggests. Tesla named the entity “Tesla Motors Vietnam Limited Liability Company.”

The planned entrance into the Vietnamese market is a good sign and move for Tesla, as it has become one of the fastest-growing EV markets in Southeast Asia. It is already among the leaders in the region in both volume and electrification rate. In the first half of this year, Vietnam led Southeast Asia in battery-electric passenger car sales at about 116,000 units, up about 71 percent year over year.

Currently, Vietnamese EV drivers rely on VinFast’s V-Green network, which has about 150,000 ports, but these are primarily reserved for VinFast vehicles. Public third-party charging is fragmented and unreliable for those who do not own chargers that are dedicated to a certain manufacturer’s vehicles.

Tesla has had mixed results in Asia as a whole, and as China remains the core part of its story in Asia, the company is evidently working on expanding its footprint on the continent. Tesla’s domestic retail deliveries fell about 12 percent year over year through the first eight months of 2026.

Model Y remains a standout individual product, holding its position as one of, if not the, best-selling vehicles in the world. However, Model 3 has been weaker than it has been in past years.

Gigafactory Shanghai, the company’s Chinese production facility, still performs very well. Wholesale volumes in terms of exports have more than doubled and now exceed domestic retail sales; Giga Shanghai builds vehicles for Europe, South Korea, Japan, Australia, and other markets. South Korea has been an explicit bright spot, with registrations doubling year-to-date and Tesla frequently appearing as the top imported brand.

Tesla just did something in South Korea that no foreign carmaker has ever done

Tesla’s entrance into Vietnam signals a broader effort to take over the Asian market and grab more market share from rivals.

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Elon Musk’s companies made up with Apple but OpenAI still on the hook

Elon Musk’s X Corp and SpaceXAI dropped their Apple antitrust suit, leaving OpenAI as defendant.

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X Corp and SpaceXAI, Elon Musk’s social platform and AI venture, have dropped Apple from the antitrust lawsuit that they filed against the iPhone maker and OpenAI last year. In a filing in the U.S. District Court for the Northern District of Texas, attorneys for X and SpaceXAI moved to dismiss the Apple portion of the case, first reported by Reuters. The filing does not explain why the companies are dropping Apple or say whether a settlement was reached.

X and SpaceXAI say they intend to keep pursuing the case against OpenAI, which remains a defendant. That resolves the dispute with one company while leaving the core allegation intact against the other, with no public accounting of what changed in between.

The lawsuit dates to August 2025, when xAI and X sued Apple and OpenAI, arguing that Apple’s decision to make ChatGPT the only generative AI chatbot built into iOS gave OpenAI an unfair structural advantage. The complaint claimed ChatGPT controlled roughly 80 percent of the chatbot market at the time, while Grok held only a few percent. It sought billions of dollars in damages and asked the court to unwind the arrangement.

Elon Musk’s xAI and X file antitrust suit against Apple and OpenAI over AI exclusivity

The filing followed weeks of Musk publicly complaining that Grok and X weren’t appearing in Apple’s “Must Have” App Store section, though Grok ranked second in the Productivity category and X ranked first in News at the time. He accused Apple of “playing politics” and warned of immediate legal action before following through days later.

Apple and OpenAI tried to get the case thrown out, but a federal judge denied both motions in November, ruling the dispute was better suited to summary judgment than an early dismissal. That decision sent the case into discovery, which is presumably what led to Monday’s filing.

The timing is notable given how Musk’s sentiment toward Apple has shifted, with Musk noting that he was open to letting Grok power a revamped Siri after a user suggested Apple replace its aging assistant with xAI’s model.

xAI, the AI venture Musk folded into X Corp last year, has since combined with SpaceX under the SpaceXAI brand. That structure now puts X, Grok and SpaceX’s rocket and satellite businesses under one roof as Musk pushes his AI ambitions beyond chatbots.

OpenAI remains the sole defendant going forward, and Musk’s companies have not said if there’s any changes to those original claims. Apple and OpenAI did not immediately respond to requests for comment on the filing.

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Why SpaceX is finishing another space-internet system that isn’t Starlink

SpaceX launched three final O3b mPower satellites Sunday, finishing a lesser known SES satellite network.

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SpaceX had an 87 minute window opening at 2:49 p.m. Eastern on Sunday to fly a Falcon 9 out of Cape Canaveral carrying the final three satellites for SES’s O3b mPower constellation, a project that has taken more than a decade to finish since Boeing and SES first signed SpaceX on for the work.

Unlike the thousands of Starlink satellites SpaceX has stacked into orbit over the years, O3b mPower flies in a different neighborhood entirely. The three new satellites, tagged F11, F12 and F13, are headed for medium Earth orbit at roughly 5,000 miles up, more than ten times higher than Starlink’s shell around 340 miles but still a small fraction of the 22,000 miles where old school geostationary satellites sit. That middle position is the whole point, because a satellite that far out needs far fewer siblings to blanket the globe than a low orbit constellation does. Essentially, SES only needed 13 satellites total to build a network offering quick, steady service that used to require thousands of spacecraft.

With most people having heard plenty about Starlink and almost nothing about O3b mPower, SES and SpaceX already blend the two networks for some customers. Both SpaceX and SES sell satellite broadband, but they’re aimed at different buyers. Starlink is built for volume, direct to consumers, RVs, homes, small businesses, plus a growing aviation and maritime business. O3b mPower skips consumers entirely and sells enterprise grade connectivity to airlines, cruise lines, offshore energy operators, telecoms needing backhaul, and governments, priced and provisioned more like a dedicated circuit.

A 2023 partnership lets cruise ships combine Starlink’s speed with O3b mPower’s steady capacity depending on what a ship needs at a given moment. Sunday’s completed 13 satellite constellation effectively finishes the medium orbit half of that pairing, years after.

Sunday’s mission was already a something on SpaceX’s manifest well before O3b mPower entered the picture. This flight marked its 29th trip to orbit, a history that includes two crewed Axiom missions, the European Space Agency’s Euclid telescope and 22 separate Starlink batches. SpaceX has landed boosters on the droneship A Shortfall of Gravitas so often that Sunday’s touchdown attempt, if it went as planned, was set to be the 661st successful Falcon booster landing to date.

For a company that pushed the Starlink constellation past 11,000 satellites back in August, almost entirely through bulk launches from California, Sunday’s flight was a reminder that SpaceX’s schedule still has room for someone else’s satellites too. SES gets a finished network built for a narrower set of customers, and Falcon 9 gets one more line on an already long resume.

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