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SpaceX’s Starship Raptor Vacuum engine plans laid out by CEO Elon Musk
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.
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.
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.
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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Donald Trump confirms ‘good’ relationship with Elon Musk after public feud
Trump stated that he and Elon Musk have spoken “on and off, a little bit” since meeting at Charlie Kirk’s memorial service in September.
United States President Donald Trump has confirmed that his relationship with Elon Musk has improved following months of tension.
Speaking with reporters aboard Air Force One, Trump stated that he and Elon Musk have spoken “on and off, a little bit” since meeting at slain conservative activist Charlie Kirk’s memorial service in September. Trump also noted that he now considers their relationship “good.”
Trump stated that his feud with Musk has cooled after ‘stupid moment’
Trump addressed the pair’s earlier feud, which unfolded publicly earlier this year after Musk publicly opposed Trump’s “Big Beautiful Bill” and later stepped away from his administration’s advisory role tied to the DOGE initiative. The U.S. president addressed the dispute, describing it as a brief lapse in judgment, as noted in an Insider report.
“He had a bad spell, he had a bad period. He had a bad moment,” Trump said. “It was a stupid moment in his life, very stupid. I’m sure he’d tell you that. But I like Elon, and I suspect I always will.”
Trump’s remarks suggest a thaw in what had been one of the United States’ most visible political rifts, which saw Musk accusing Trump of being on Epstein’s list and Trump threatening to take away Tesla and SpaceX’s subsidies. In his recent comments, however, Trump noted that “I like Elon, I’ve always liked him.”
Musk has mostly stayed quiet on Trump, but he still criticizes administration officials
Musk has publicly toned down his criticism of Trump in recent months, pausing discussion of a third political party he once floated after Trump’s megabill passed. While his stance toward the former president appears to have softened, with the two men publicly making peace during Kirk’s memorial, Musk has continued to spar with members of Trump’s administration.
Just last week, he engaged in a dispute with Transportation Secretary Sean Duffy over NASA leadership after Duffy opened one of SpaceX’s contracts for review. Musk expressed his frustration against Duffy on X, stating that “Sean Dummy is trying to kill NASA” and pledging that SpaceX would be taking humans back to the Moon with Starship before any other company.
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IF Metall chair to Elon Musk: “Give us a chance” as Tesla Sweden strike hits 2 years
The official emphasized that Swedish unions function under a cooperative framework that benefits both employers and workers.
IF Metall’s strike against Tesla Sweden has entered its third year, with union chair Marie Nilsson urging Elon Musk to reconsider his perception of organized labor.
Speaking ahead of the strike’s second anniversary, Nilsson stated that Tesla should understand that Swedish unions operate differently from their American counterparts, and they deserve the opportunity to prove it.
IF Metall leader urges Tesla to understand Sweden’s system
In an interview with Dagens Arbete (DA), Nilsson stated that Tesla’s skepticism toward labor unions likely stems from the company’s experience in the United States, where labor organizations have historically taken a more combative approach. She emphasized that Swedish unions function under a cooperative framework that benefits both employers and workers.
“I can certainly understand that Elon Musk and Tesla are skeptical of the trade union movement. They have experience with American unions that operate in a completely different environment and that have to be militant in a different way.
“I would say: Don’t compare Swedish unions with American ones. Let’s give us a chance. Signing a collective agreement in Sweden also does not mean that you are committed to collective agreements in the rest of the world, but it is the practical system we have here to regulate the conditions,” Nilsson stated.
Nilsson rejected the idea that Tesla Sweden is being unfairly targeted
The IF Metall leader also reflected on the conflict’s duration, calling it unprecedented in Swedish labor history. While she admitted the union should have organized Tesla workers earlier, she maintained that the movement remains determined. “No one can possibly imagine what it is like not to go to work for two years,” Nilsson said, praising members who have continued to maintain their protest against the EV maker.
Nilsson also rejected any notion that the union is targeting Tesla unfairly. “Tesla is not a poor little company that we are trying to crush in any way,” she said. “But this is a global player, and we cannot accept that they should have different conditions in Sweden than other entrepreneurs have.”
She confirmed that IF Metall is now prepared to take greater risks, especially after the Swedish Mediation Institute stepped back from talks. “It is impossible for us to do anything else. This is a large and important player, and therefore we need to take this conflict. It is impossible for us to do anything else,” Nilsson said.
Elon Musk
Tesla analyst: ‘near zero chance’ Elon Musk’s $1T comp package is rejected
“There is a near-zero chance that $TSLA shareholders will vote down Elon’s new proposed comp plan at the Nov 6 shareholders’ meeting.”
A Tesla analyst says there is “zero chance” that CEO Elon Musk’s new compensation package is rejected, a testament to the loyalty and belief many shareholders and investors have in the frontman.
Tesla investors will vote on November 6 at the annual Shareholder Meeting to approve a new compensation package for Musk, revealed by the company’s Board of Directors earlier this month.
The package, if approved, would give Musk the opportunity to earn $1 trillion in stock, an ownership concentration of over 27 percent (a major request of Musk’s), and a solidified future at the company.
The Tesla Community on X, the social media platform Musk bought in 2023, is overwhelmingly in favor of the pay package, though a handful of skeptics remain.
Nevertheless, the big pulls of this vote are held by proxy firms and other large-scale investors. Two of them, Institutional Shareholder Services (ISS) and Glass Lewis, said they would be voting against Musk’s proposed compensation plan.
Tesla CEO Elon Musk’s $1 trillion pay package hits first adversity from proxy firm
Today, the State Board of Administration of Florida (SBA) said it would vote in favor of Musk’s newly-proposed pay day, making it the first large-scale shareholder to announce it would support the CEO’s pay.
One analyst said that Musk’s payday is inevitable. Gary Black of the Future Fund said today there is a “near-zero chance” that shareholders will allow Musk’s pay package to be rejected:
“There is a near-zero chance that $TSLA shareholders will vote down Elon’s new proposed comp plan at the Nov 6 shareholders’ meeting.”
He added an alternative perspective from Wedbush’s Dan Ives, who said that he had a better chance of starting for the New York Yankees than the comp package not being approved.
There is a near zero chance that $TSLA shareholders will vote down Elon’s new proposed comp plan at the Nov 6 shareholders’ meeting. As Wedbush analyst Dan Ives (@divestech) colorfully put it in a Yahoo Finance interview on October 23rd: “I have a better chance of starting for…
— Gary Black (@garyblack00) October 27, 2025
Black’s the Future Fund sold its Tesla holdings earlier this year. He explained that the firm believed the company’s valuation was too disconnected from fundamentals, citing the P/E ratio of 188x and declining earnings estimates.
The firm maintained its $310 price target, and shares were trading at $356.90 that day.
Shares closed at $452.42 today.
The latest predictions from betting platform Kalshi have shown Musk’s comp package has a 94 percent chance of being approved:
— Kalshi (@Kalshi) October 20, 2025
Donald Trump confirms ‘good’ relationship with Elon Musk after public feud
IF Metall chair to Elon Musk: “Give us a chance” as Tesla Sweden strike hits 2 years
Tesla analyst: ‘near zero chance’ Elon Musk’s $1T comp package is rejected
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