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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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Tesla executive moves on after 13 years: ‘It has been a privilege to serve’
“It is challenging to encapsulate 13 years in a single post. The journey at Tesla has been one of continuous evolution. From the technical intricacies of designing, building, and operating one of the world’s largest AI clusters to impactful contributions in IT, Security, Sales, and Service, it has been a privilege to serve,” Jegannathan said in the post.
Tesla executive Raj Jegannathan is moving on from the company after 13 years, he announced on LinkedIn on Monday.
“It is challenging to encapsulate 13 years in a single post. The journey at Tesla has been one of continuous evolution. From the technical intricacies of designing, building, and operating one of the world’s largest AI clusters to impactful contributions in IT, Security, Sales, and Service, it has been a privilege to serve,” Jegannathan said in the post.
After starting as a Senior Staff Engineer in Fremont back in November 2012, Jegannathan slowly worked his way through the ranks at Tesla. His most recent role was Vice President of IT/AI Infrastructure, Business Apps, and Infosec.
However, it was reported last year that Jegannathan had taken on a new role, which was running the North American sales team following the departure of Troy Jones, who had held the position previously.
While Jegannathan’s LinkedIn does not mention this position specifically, it seemed to be accurate, considering Tesla had not explicitly promoted any other person to the role.
It is a big loss for Tesla, but not a destructive departure. Jegannathan was one of the few company executives who answered customer and fan questions on X, a unique part of the Tesla ownership experience.
Tesla to offer Full Self-Driving gifting program: here’s how it will work
It currently remains unclear if Jegannathan was removed from the position or if he left under his own accord.
“As I move on, I do so with a full heart and excitement for what lies ahead. Thank you, Tesla, for this wonderful opportunity!” he concluded.
The departure marks a continuing trend of executives leaving the company, as the past 24 months have seen some significant turnover at the executive level.
Tesla has shown persistently elevated executive turnover over the past two years, as names like Drew Baglino, Rohan Patel, Rebecca Tinucci, Daniel Ho, Omead Afshar, Milan Kovac, and Siddhant Awasthi have all been notable names to exit the company in the past two years.
There are several things that could contribute to this. Many skeptics will point to Elon Musk’s politics, but that is not necessarily the case.
Tesla is a difficult, but rewarding place to work. It is a company that requires a lot of commitment, and those who are halfway in might not choose to stick around. Sacrificing things like time with family might not outweigh the demands of Tesla and Musk.
Additionally, many of these executives have made a considerable amount of money thanks to stock packages the company offers to employees. While many might be looking for new opportunities, some might be interested in an early retirement.
Tesla is also in the process of transitioning away from its most notable division, automotive. While it still plans to manufacture cars in the millions, it is turning more focus toward robotics and autonomy, and these plans might not align with what some executives might want for themselves. There are a wide variety of factors in the decision to leave a job, so it is important not to immediately jump to controversy.
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Lemonade launches Tesla FSD insurance program in Oregon
The program was announced by Lemonade co-founder Shai Wininger on social media platform X.
Tesla drivers in Oregon can now receive significant insurance discounts when using FSD, following the launch of Lemonade’s new Autonomous Car insurance program.
The program was announced by Lemonade co-founder Shai Wininger on social media platform X.
Lemonade launches FSD-based insurance in Oregon
In a post on X, Wininger confirmed that Lemondade’s Autonomous Car insurance product for Tesla is now live in Oregon. The program allows eligible Tesla owners to receive roughly 50% off insurance costs for every mile driven using Tesla’s FSD system.
“And… we’re ON. @Lemonade_Inc’s Autonomous Car for @Tesla FSD is now live in Oregon. Tesla drivers in Oregon can now get ~50% off their Tesla FSD-driven miles + the best car insurance experience in the US, bar none,” Wininger wrote in his post.
As per Lemonade on its official website, the program is built on Tesla’s safety data, which indicates that miles driven using FSD are approximately twice as safe as those driven manually. As a result, Lemonade prices those miles at a lower rate. The insurer noted that as FSD continues to improve, associated discounts could increase over time.
How Lemonade tracks FSD miles
Lemonade’s FSD discount works through a direct integration with Tesla vehicles, enabled only with a driver’s explicit permission. Once connected, the system distinguishes between miles driven manually and those driven using FSD, applying the discount automatically to qualifying miles.
There is no minimum FSD usage requirement. Drivers who use FSD occasionally still receive discounted rates for those miles, while non-FSD miles are billed at competitive standard rates. Lemonade also emphasized that coverage and claims handling remain unchanged regardless of whether a vehicle is operating under manual control or FSD at the time of an incident.
The program is currently available only to Teslas equipped with Hardware 4 or newer, running firmware version 2025.44.25.5 or later. Lemonade also allows policyholders to bundle Tesla insurance with renters, homeowners, pet, or life insurance policies for additional savings.
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Tesla exec: Preparations underway but no firm timeline yet for FSD rollout in China
The information was related by Tesla China Vice President Grace Tao in a comment to local media.
Tesla has not set a specific launch date for Full Self-Driving in China, despite the company’s ongoing preparations for a local FSD rollout.
The information was related by Tesla China Vice President Grace Tao in a comment to local media.
Tesla China prepares FSD infrastructure
Speaking in a recent media interview, the executive confirmed that Tesla has established a local training center in China to support the full adaptation of FSD to domestic driving conditions, as noted in a report from Sina News. However, she also noted that the company does not have a specific date when FSD will officially roll out in China.
“We have set up a local training center in China specifically to handle this adaptation,” Tao said. “Once officially released, it will demonstrate a level of performance that is no less than, and may even surpass, that of local drivers.”
Tao also emphasized the rapid accumulation of data by Tesla’s FSD system, with the executive highlighting that Full Self-Driving has now accumulated more than 7.5 billion miles of real-world driving data worldwide.
Possible 2026 rollout
The Tesla executive’s comments come amidst Elon Musk’s previous comments suggesting that regulatory approval in China could arrive sometime this 2026. During Tesla’s annual shareholder meeting in November 2025, Musk clarified that FSD had only received “partial approval” in China, though full authorization could potentially arrive around February or March 2026.
Musk reiterated that timeline at the World Economic Forum in Davos, when he stated that FSD approval in China could come as early as February.
Tesla’s latest FSD software, version 14, is already being tested in more advanced deployments in the United States. The company has also started the rollout of its fully unsupervised Robotaxis in Austin, Texas, which no longer feature safety monitors.
Tesla executive moves on after 13 years: ‘It has been a privilege to serve’
Lemonade launches Tesla FSD insurance program in Oregon
