News
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.
Check out Teslarati’s Marketplace! We offer Tesla accessories, including for the Tesla Cybertruck and Tesla Model 3.
Elon Musk
SpaceX targets 150Mbps per user for upgraded Starlink Direct-to-Cell
If achieved, the 150Mbps goal would represent a significant jump from the current performance of Starlink Direct-to-Cell.
SpaceX is targeting peak download speeds of 150Mbps per user for its next-generation Direct-to-Cell Starlink service. The update was shared by SpaceX Spectrum & Regulatory Affairs Lead Udrivolf Pica during the International Telecommunication Union’s Space Connect conference.
“We are aiming at peak speeds of 150Mbps per user,” Pica said during the conference. “So something incredible if you think about the link budgets from space to the mobile phone.”
If achieved, the 150Mbps goal would represent a significant jump from the current performance of Starlink Direct-to-Cell.
Today, SpaceX’s cellular Starlink service, offered in partnership with T-Mobile under the T-Satellite brand, provides speeds of roughly 4Mbps per user. The service is designed primarily for texts, low-resolution video calls, and select apps in locations that traditionally have no cellular service.
By comparison, Ookla data shows median 5G download speeds of approximately 309Mbps for T-Mobile and 172Mbps for AT&T in the United States, as noted in a PCMag report. While 150Mbps would still trail the fastest terrestrial 5G networks, it would place satellite-to-phone broadband much closer to conventional carrier performance, even in remote areas.
Pica indicated that the upgraded system would support “video, voice, and data services, clearly,” moving beyond emergency connectivity and basic messaging use cases.
To reach that target, SpaceX plans to upgrade its existing Starlink Direct-to-Cell satellites and add significant new capacity. The company recently acquired access to radio spectrum from EchoStar, which Pica described as key to expanding throughput.
“More spectrum means a bigger pipeline, and this means that we can expand what we can do with partners. We can expand the quality of service. And again, we can do cellular broadband basically, cellular broadband use cases, like AI or daily connectivity needs,” he stated.
SpaceX has also requested regulatory approval to deploy 15,000 additional Direct-to-Cell satellites, beyond the roughly 650 currently supporting the system. The upgraded architecture is expected to begin rolling out in late 2027.
News
Tesla seeks approval to test FSD Supervised in new Swedish city
Tesla has applied to conduct local Full Self-Driving (Supervised) testing in the city of Jönköping, Sweden.
Tesla has applied to conduct local Full Self-Driving (Supervised) testing in the city of Jönköping, Sweden.
As per local outlet Jönköpings-Posten, Tesla has contacted the municipality with a request to begin FSD (Supervised) tests in the city. The company has already received approval to test its Full Self-Driving (Supervised) software in several Swedish municipalities, as well as on the national road network.
Sofia Bennerstål, Tesla’s Head of Public Policy for Northern Europe, confirmed that an application has been submitted for FSD’s potential tests in Jönköping.
“I can confirm that we have submitted an application, but I cannot say much more about it,” Bennerstål told the news outlet. She also stated that Tesla is “satisfied with the tests” in the region so far.
The planned tests in Jönköping would involve a limited number of Tesla-owned vehicles. Trained Tesla safety drivers would remain behind the wheel and be prepared to intervene if necessary.
Tesla previously began testing in Nacka municipality after receiving local approval. At the time, the company stated that cooperation between authorities, municipalities, and industry enables technological progress and helps integrate future transport systems into real-world traffic conditions, as noted in an Allt Om Elbil report.
If approved, Jönköping would become the latest Swedish municipality to allow local Full Self-Driving (Supervised) testing.
Tesla’s Swedish testing program is part of the company’s efforts to validate its supervised autonomous driving software in everyday traffic environments. Municipal approvals allow Tesla to gather data in urban settings that include roundabouts, complex intersections, and mixed traffic conditions.
Sweden has become an increasingly active testing ground for Tesla’s driver-assistance software in Europe, with regulatory coordination between local authorities and national agencies enabling structured pilot programs.
Elon Musk
Microsoft partners with Starlink to expand rural internet access worldwide
The update was shared ahead of Mobile World Congress.
Microsoft has announced a new collaboration with Starlink as part of its expanding digital access strategy, following the company’s claim that it has extended internet connectivity coverage to more than 299 million people worldwide.
The update was shared ahead of Mobile World Congress, where Microsoft detailed how it surpassed its original goal of bringing internet access to 250 million people by the end of 2025.
In a blog post, Microsoft confirmed that it is now working with Starlink to expand connectivity in rural and hard-to-reach regions.
“Through our collaboration with Starlink, Microsoft is combining low-Earth orbit satellite connectivity with community-based deployment models and local ecosystem partnerships,” the company wrote.
The partnership is designed to complement Microsoft’s existing work with local internet providers and infrastructure companies across Africa, Latin America, and India, among other areas. Microsoft noted that traditional infrastructure alone cannot meet demand in some regions, making low-Earth orbit satellite connectivity an important addition.
Kenya was cited as an early example. Working with Starlink and local provider Mawingu Networks, Microsoft is supporting connectivity for 450 community hubs in rural and underserved areas. These hubs include farmer cooperatives, aggregation centers, and digital access facilities intended to support agricultural productivity and AI-enabled services.
Microsoft stated that 2.2 billion people globally remain offline, and that connectivity gaps risk widening as AI adoption accelerates.
Starlink’s expanding constellation, now numbering more than 9,700 satellites in orbit, provides near-global coverage, making it one of the few systems capable of delivering broadband to remote regions without relying on terrestrial infrastructure.
Starlink is expected to grow even more in the coming years as well, especially as SpaceX transitions its fleet to Starship, which is capable of carrying significantly larger payloads compared to its current workhorse, the Falcon 9.
SpaceX targets 150Mbps per user for upgraded Starlink Direct-to-Cell
Tesla seeks approval to test FSD Supervised in new Swedish city
