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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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Elon Musk said he is planning to give “every one of his SpaceX shares to every kid in America” in 2027, stating that “this will be the first of many.”
SpaceX went public earlier this year, and its stock price has been relatively stable since leveling off shortly after its IPO. Based on its current price, it’s a gift of just over $10 billion to children across the United States.
It appears to be closely related to President Donald Trump’s bank accounts for children, which were set up earlier this year as Trump Accounts.
Just hours earlier, Anthropic had announced the establishment of its Anthropic Public Benefit Fund, “a new wholly-owned entity dedicated entirely to public benefit.” Musk responded by stating he recommended “giving the shares directly to the public,” and that he would be doing it that way.
Just a little bit later, Musk said children across the U.S. would be getting a share from him:
Next year, I will give one of my SpaceX shares to every kid in America.
This will be the first of many.
— Elon Musk (@elonmusk) October 19, 2026
There are roughly 70 million children, meaning someone under the age of 18, in the United States, according to the Federal Interagency Forum on Child and Family Statistics. Musk’s ownership of SpaceX stock shows he has around 849 million Class A shares of SpaceX stock, according to filings with the SEC.
Elon Musk revealed in a post on X that “Permits were impossible to get,” explaining the fate of The Boring Company’s most ambitious East Coast proposal.
The comment responded to a query about what became of his July 20, 2017 announcement that he had “just received verbal govt approval” for an underground Hyperloop connecting New York City, Philadelphia, Baltimore, and Washington, D.C., capable of carrying passengers from the Big Apple to the Nation’s Capital in just 29 minutes.
The Boring Company receives verbal ‘approval’ to build NY to DC Hyperloop tunnel
The 2017 post, which envisioned city-center stations and multiple elevators in each city, sparked immediate scrutiny. Local and state officials in New York, Philadelphia, Baltimore, and D.C. said they had no knowledge of any approval. A White House spokesperson confirmed only “promising conversations” about the transformative infrastructure.
Musk clarified shortly after that there was “still a lot of work” to do for formal approvals.
@cybrtrkguy Permits were impossible to get
— Elon Musk (@elonmusk) October 19, 2026
Limited progress followed, as Maryland Governor Larry Hogan’s administration issued a conditional utility permit and supported work near Fort Meade. In 2018, Washington, D.C., granted a preliminary permit for site preparation and excavation on a vacant lot at 53 New York Ave. NE in the NoMa neighborhood, which The Boring Company said could become a station.
A draft environmental assessment for a D.C.-Baltimore segment was released in 2019. Yet, by April 2021, the company had removed the project from its website, and the Federal Highway Administration reported receiving no indication of further interest. Communication with Maryland officials had ceased.
The full corridor would have required coordination among the District of Columbia, Maryland, Pennsylvania, New York, the Federal Highway Administration, the Army Corps of Engineers, the National Park Service, and other agencies.
Environmental reviews under the National Environmental Policy Act, utility clearances, and approvals for novel infrastructure added to the overall complexity of the project and its approval.
Speculation on the permitting barriers centers around a few factors, but a multi-state, multi-level route involving unproven high-speed vacuum-tube technology inherently triggers exhaustive safety, environmental, and engineering reviews that can stretch for years, even for conventional projects.
There are also other elements, of course, like officials who may face political exposure if a privately funded, untested system encountered anything such as cost overruns, delays, or safety issues. On the outset of this project, there were limited things such as engineering plans or demonstrated technology maturity, which also added to the potential skepticism.
The East Coast vision for Boring Co., once framed as a privately funded revolution that could reshape Northeast travel, quietly ended without construction of the promised network. Musk’s recent statement frames the outcome as a regulatory impasse, unfortunate but not unexpected.
Tesla CEO Elon Musk took to his social media platform X on Sunday to remind everyone that the Roadster’s true meaning is not about company growth or adding dollars to shareholders’ pockets. Sometimes, you just do things because you can.
Following the Roadster’s epic unveiling event last Thursday, skeptics and critics of the company or the project itself came out to say that the vehicle is a pointless project because it is not geared toward growing the company, delivering supreme margins for profitability, nor does it contribute to the big picture of Artificial/Super Intelligence.
But that’s just the thing: Roadster is not meant to be some shareholder dream; it’s meant to be a vehicle that people buy just because it is something awesome, unique, and the first of its kind.
Tesla Roadster: Three configs, one can fly, 0-60 in 0.8 seconds
Musk had to remind those who are skeptical about the Roadster’s importance to the company mission that while it is not a major contributor to Tesla’s long-term goals, it is something that is being built just because it can be:
“Optimus and Cybercab will be the vast majority of Tesla’s value. The only things that will scale to incredible size (K2 and beyond) economically are super intelligence, robots, solar power, and mass to space. And, of course, if you have the first two, the rest will follow. But Roadster is super cool, so we’re doing it anyway.”
Musk has said on many occasions that Optimus would be the project that would make up the vast majority of Tesla’s value in the coming years.
Robotics will be a major focus of Tesla over the coming years, especially as Musk believes Optimus will enable work to be optional for humans and will enable what he calls “High Universal Income.”
Optimus and Cybercab will be the vast majority of Tesla’s value.
The only things that will scale to incredible size (K2 and beyond) economically are super intelligence, robots, solar power and mass to space.
And, of course, if you have the first two, the rest will follow.
But Roadster is super cool, so we’re doing it anyway.
— Elon Musk (@elonmusk) October 18, 2026
Cybercab will be a passive income opportunity for owners, Musk and Tesla have said for a very long time, as a fleet of self-driving vehicles will operate within a ride-hailing Robotaxi service that won’t require a human driver to be present.
Tesla investors are more than enthusiastic about the company’s future projects, at least from a general consensus perspective. However, it is important to note that the Roadster is a fun and cool project that pushes the boundaries of what people thought was possible for an automobile.
What we saw last week was the first true example of a flying car, and despite the backlash about how it might not contribute to Tesla’s grand ambitions, it’s okay to have fun sometimes, too.
Elon Musk will give ‘every kid in America’ a SpaceX share in 2027
Elon Musk reveals why Boring Co’s biggest East Coast project never happened
Tesla CEO Elon Musk reminds everyone about Roadster’s true meaning
SpaceX reveals how its 1 Million AI satellite network will work and prevent space collisions
Tesla Roadster: Three configs, one can fly, 0-60 in 0.8 seconds
