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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
Elon Musk reiterates Tesla Optimus’ most sci-fi potential yet
Musk shared his comments in a series of posts on social media platform X.
Elon Musk recently reiterated one of the most ambitious forecasts for Tesla’s humanoid robot, Optimus, stating it could become the first real-world example of a Von Neumann machine. He also noted once more that Optimus would be Tesla’s biggest product.
Musk shared his comments in a series of posts on social media platform X.
Optimus as a von Neumann machine
In response to a post on X that pondered on sci-fi timelines becoming real, Musk wrote that “Optimus will be the first Von Neumann machine, capable of building civilization by itself on any viable planet.” In a separate post, Musk wrote that Optimus will be Tesla’s “biggest product ever,” a phrase he has used in the past to describe the humanoid robot’s importance to the electric vehicle maker.
A Von Neumann machine is a class of theoretical self-replicating systems originally proposed in the mid-20th century by the mathematician John von Neumann. In his concept, von Neumann described machines that could travel to other worlds, use local materials to create copies of themselves, and carry out large-scale tasks without outside intervention.
Elon Musk’s broader plans
Considering Musk’s comments, it appears that Optimus would eventually be capable of performing complex work autonomously in environments beyond Earth. If Optimus could achieve such a feat, it could very well unlock humanity’s capability to explore locations beyond Earth. The idea of space exploration becomes more than feasible.
Elon Musk has discussed space-based AI compute, large-scale robotic production, and the role of SpaceX’s Starship in transporting hardware and materials to other planets. While Musk did not detail how Optimus would fit with SpaceX’s exploration activities, his Von Neumann machine comments suggest he is looking at Tesla’s robotics as part of a potential interplanetary ecosystem.
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Tesla China January wholesale sales rise 9% year-on-year
Tesla reported January wholesale sales of 69,129 China-made vehicles, as per data released by the China Passenger Car Association.
Tesla China reported January wholesale sales of 69,129 Giga Shanghai-made vehicles, as per data released by the China Passenger Car Association (CPCA). The figure includes both domestic sales and exports from Gigafactory Shanghai.
The total represented a 9.32% increase from January last year but a 28.86% decline from December’s 97,171 units.
China EV market trends
The CPCA estimated that China’s passenger new energy vehicle wholesale volume reached about 900,000 units in January, up 1% year-on-year but down 42% from December. Demand has been pressured by the start-of-year slow season, a 5% additional purchase tax cost, and uncertainty around the transition of vehicle trade-in subsidies, as noted in a report from CNEV Post.
Market leader BYD sold 210,051 NEVs in January, down 30.11% year-on-year and 50.04% month-on-month, as per data released on February 1. Tesla China’s year-over-year growth then is quite interesting, as the company’s vehicles seem to be selling very well despite headwinds in the market.
Tesla China’s strategies
To counter weaker seasonal demand, Tesla China launched a low-interest financing program on January 6, offering up to seven-year terms on select produced vehicles. The move marked the first time an automaker offered financing of that length in the Chinese market.
Several rivals, including Xiaomi, Li Auto, XPeng, and NIO, later introduced similar incentives. Tesla China then further increased promotions on January 26 by reinstating insurance subsidies for the Model 3 sedan. The CPCA is expected to release Tesla’s China retail sales and export breakdown later this month.
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Tesla’s Apple CarPlay ambitions are not dead, they’re still in the works
For what it’s worth, as a Tesla owner, I don’t particularly see the need for CarPlay, as I have found the in-car system that the company has developed to be superior. However, many people are in love with CarPlay simply because, when it’s in a car that is capable, it is really great.
Tesla’s Apple CarPlay ambitions appeared to be dead in the water after a large amount of speculation late last year that the company would add the user interface seemed to cool down after several weeks of reports.
However, it appears that CarPlay might make its way to Tesla vehicles after all, as a recent report seems to indicate that it is still being worked on by software teams for the company.
The real question is whether it is truly needed or if it is just a want by so many owners that Tesla is listening and deciding to proceed with its development.
Back in November, Bloomberg reported that Tesla was in the process of testing Apple CarPlay within its vehicles, which was a major development considering the company had resisted adopting UIs outside of its own for many years.
Nearly one-third of car buyers considered the lack of CarPlay as a deal-breaker when buying their cars, a study from McKinsey & Co. outlined. This could be a driving decision in Tesla’s inability to abandon the development of CarPlay in its vehicles, especially as it lost a major advantage that appealed to consumers last year: the $7,500 EV tax credit.
Tesla owners propose interesting theory about Apple CarPlay and EV tax credit
Although we saw little to no movement on it since the November speculation, Tesla is now reportedly in the process of still developing the user interface. Mark Gurman, a Bloomberg writer with a weekly newsletter, stated that CarPlay is “still in the works” at Tesla and that more concrete information will be available “soon” regarding its development.
While Tesla already has a very capable and widely accepted user interface, CarPlay would still be an advantage, considering many people have used it in their vehicles for years. Just like smartphones, many people get comfortable with an operating system or style and are resistant to using a new one. This could be a big reason for Tesla attempting to get it in their own cars.
Tesla gets updated “Apple CarPlay” hack that can work on new models
For what it’s worth, as a Tesla owner, I don’t particularly see the need for CarPlay, as I have found the in-car system that the company has developed to be superior. However, many people are in love with CarPlay simply because, when it’s in a car that is capable, it is really great.
It holds one distinct advantage over Tesla’s UI in my opinion, and that’s the ability to read and respond to text messages, which is something that is available within a Tesla, but is not as user-friendly.
With that being said, I would still give CarPlay a shot in my Tesla. I didn’t particularly enjoy it in my Bronco Sport, but that was because Ford’s software was a bit laggy with it. If it were as smooth as Tesla’s UI, which I think it would be, it could be a really great addition to the vehicle.
Elon Musk reiterates Tesla Optimus’ most sci-fi potential yet
Tesla China January wholesale sales rise 9% year-on-year
