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.
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Elon Musk
Tesla investors will be shocked by Jim Cramer’s latest assessment
Jim Cramer is now speaking positively about Tesla, especially in terms of its Robotaxi performance and its perception as a company.
Tesla investors will be shocked by analyst Jim Cramer’s latest assessment of the company.
When it comes to Tesla analysts, many of them are consistent. The bulls usually stay the bulls, and the bears usually stay the bears. The notable analysts on each side are Dan Ives and Adam Jonas for the bulls, and Gordon Johnson for the bears.
Jim Cramer is one analyst who does not necessarily fit this mold. Cramer, who hosts CNBC’s Mad Money, has switched his opinion on Tesla stock (NASDAQ: TSLA) many times.
He has been bullish, like he was when he said the stock was a “sleeping giant” two years ago, and he has been bearish, like he was when he said there was “nothing magnificent” about the company just a few months ago.
Now, he is back to being a bull.
Cramer’s comments were related to two key points: how NVIDIA CEO Jensen Huang describes Tesla after working closely with the Company through their transactions, and how it is not a car company, as well as the recent launch of the Robotaxi fleet.
Jensen Huang’s Tesla Narrative
Cramer says that the narrative on quarterly and annual deliveries is overblown, and those who continue to worry about Tesla’s performance on that metric are misled.
“It’s not a car company,” he said.
He went on to say that people like Huang speak highly of Tesla, and that should be enough to deter any true skepticism:
“I believe what Musk says cause Musk is working with Jensen and Jensen’s telling me what’s happening on the other side is pretty amazing.”
Tesla self-driving development gets huge compliment from NVIDIA CEO
Robotaxi Launch
Many media outlets are being extremely negative regarding the early rollout of Tesla’s Robotaxi platform in Austin, Texas.
There have been a handful of small issues, but nothing significant. Cramer says that humans make mistakes in vehicles too, yet, when Tesla’s test phase of the Robotaxi does it, it’s front page news and needs to be magnified.
He said:
“Look, I mean, drivers make mistakes all the time. Why should we hold Tesla to a standard where there can be no mistakes?”
It’s refreshing to hear Cramer speak logically about the Robotaxi fleet, as Tesla has taken every measure to ensure there are no mishaps. There are safety monitors in the passenger seat, and the area of travel is limited, confined to a small number of people.
Tesla is still improving and hopes to remove teleoperators and safety monitors slowly, as CEO Elon Musk said more freedom could be granted within one or two months.
News
Tesla launches ultra-fast V4 Superchargers in China for the first time
Tesla has V4 Superchargers rolling out in China for the first time.
Tesla already has nearly 12,000 Supercharger piles across mainland China. However, the company just initiated the rollout of the ultra-fast V4 Superchargers in China for the first time, bringing its quick-charging piles to the country for the first time since their launch last year.
The first batch of V4 Superchargers is now officially up and running in China, the company announced in a post on Chinese social media outlet Weibo today.
The company said in the post:
“The first batch of Tesla V4 Superchargers are online. Covering more service areas, high-speed charging is more convenient, and six-layer powerful protection such as rain and waterproof makes charging very safe. Simultaneously open to non-Tesla vehicles, and other brands of vehicles can also be charged. There are more than 70,000 Tesla Superchargers worldwide. The charging network layout covers 100% of the provincial capitals and municipalities in mainland China. More V4 Superchargers will be put into use across the country. Optimize the charging experience and improve energy replenishment efficiency. Tesla will accompany you to the mountains, rivers, lakes, and seas with pure electricity!”
The first V4 Superchargers Tesla installed in China are available in four cities across the country: Shanghai, Zhejiang, Gansu, and Chongqing.
Credit: Tesla China
Tesla has over 70,000 Superchargers worldwide. It is the most expansive and robust EV charging network in the world. It’s the main reason why so many companies have chosen to adopt Tesla’s charging connector in North America and Europe.
In China, some EVs can use Tesla Superchargers as well.
The V4 Supercharger is capable of charging vehicles at speeds of up to 325kW for vehicles in North America. This equates to over 1,000 miles per hour of charging.
Elon Musk
Elon Musk hints at when Tesla could reduce Safety Monitors from Robotaxi
Tesla could be reducing Safety Monitors from Robotaxi within ‘a month or two,’ CEO Elon Musk says.
Elon Musk hinted at when Tesla could begin reducing Safety Monitors from its Robotaxis. Safety Monitors are Tesla employees who sit in the front passenger seat during the driverless rides, and are there to ensure safety for occupants during the earliest rides.
Tesla launched its Robotaxi fleet in Austin last Sunday, and after eight days, videos and reviews from those who have ridden in the driverless vehicles have shown that the suite is safe, accurate, and well coordinated. However, there have been a few hiccups, but nothing that has put anyone’s safety in danger.
A vast majority — close to all of the rides — at least according to those who have ridden in the Robotaxi, have been performed without any real need for human intervention. We reported on what was the first intervention last week, as a Safety Monitor had to step in and stop the vehicle in a strange interaction with a UPS truck.
Watch the first true Tesla Robotaxi intervention by safety monitor
The Tesla and UPS delivery truck were going for the same street parking space, and the Tesla began to turn into it. The UPS driver parallel parked into the spot, which was much smaller than his truck. It seemed to be more of an instance of human error instead of the Robotaxi making the wrong move. This is something that the driverless cars will have to deal with because humans are aggressive and sometimes make moves they should not.
The Safety Monitors have not been too active in the vehicles. After all, we’ve only seen that single instance of an intervention. There was also an issue with the sun, when the Tesla braked abnormally due to the glare, but this was an instance where the car handled the scenario and proceeded normally.
With the Robotaxi fleet operating impressively, some are wondering when Tesla will begin scaling back both the Safety Monitors and Teleoperators that it is using to ensure safety with these early rides.
CEO Elon Musk answered the inquiry by stating, “As soon as we feel it is safe to do so. Probably within a month or two.”
As soon as we feel it is safe to do so.
Probably within a month or two. We continue to improve the Tesla AI with each mile driven.
— Elon Musk (@elonmusk) June 30, 2025
Musk’s response seems to confirm that there will be fewer Teleoperators and Safety Monitors in the coming months, but there will still be some within the fleet to ensure safety. Eventually, that number will get to zero.
Reaching a point where Tesla’s Robotaxi is driverless will be another significant milestone for the company and its path to fully autonomous ride-sharing.
Eventually, Tesla will roll out these capabilities to consumer-owned vehicles, offering them a path to generate revenue as their car operates autonomously and completes rides.
For now, Tesla is focusing on perfecting the area of Austin where it is currently offering driverless rides for just $4.20 to a small group of people.
Tesla investors will be shocked by Jim Cramer’s latest assessment
Tesla launches ultra-fast V4 Superchargers in China for the first time
Elon Musk hints at when Tesla could reduce Safety Monitors from Robotaxi
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