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SpaceX wiggles Starhopper’s Raptor engine, tests parts ahead of hover test debut

Repeating a test conducted in June with Raptor SN04, SpaceX tested Starhopper and Raptor SN06's thrust vectoring capabilities on July 12th. (NASASpaceflight - bocachicagal)

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On the evening of July 12th, SpaceX technicians put Starhopper’s freshly-installed Raptor – serial number 06 (SN06) – through a simple but decidedly entertaining test, effectively wiggling the engine in circles.

Designed to verify that Raptor’s thrust vectoring capabilities are in order and ensure that Starhopper and the engine are properly communicating, the wiggle test is a small but critical part of pre-flight acceptance and a good indicator that the low-fidelity Starship prototype is nearing its first hover test(s). Roughly 48 hours after a successful series of wiggles, Starhopper and Raptor proceeded into the next stage of pre-flight acceptance, likely the final more step before a tethered static fire.

Routine for all Falcon rockets, SpaceX’s exceptionally rigorous practice of static firing all hardware at least once (and often several times) before launch has unsurprisingly held firm as the company proceeds towards integrated Starhopper and Starship flight tests. Despite the fact that Raptor SN06 completed a static fire as recently July 10th, SpaceX will very likely put Starhopper and its newly-installed Raptor through yet another pre-flight static fire, perhaps its fourth or fifth test this month.

Although it would undoubtedly be easier, cheaper, and faster to skip that post-delivery static fire, it will simultaneously lower the risk of Raptor failing mid-flight and verify that Starhopper itself is healthy and ready for untethered hovering. Although SpaceX could likely live without Starhopper in the event that it’s lost during flight-testing, any failure capable of destroying the vehicle itself is at least as capable of severely damaging or completely destroying the spartan but still expansive test and launch facilities the company built over the course of several months.

SpaceX has been hard at work gradually building, expanding, and upgrading its South Texas launch facilities since December 2018. (NASASpaceflight – bocachicagal, 04/27/2019)

Would you like some testing with your testing?

Follow July 12th’s nighttime Raptor wiggle test, July 13th was mainly quiet and filled with inspections of Starhopper, Raptor, and other various work. The day after, however, SpaceX proceeded through several hours of propellant loading, ending with what looked like less energetic versions of the Raptor preburner ignition tests Starhopper previously performed with Raptor SN02.

In a staged-combustion engine like Raptor, getting from the supercool liquid oxygen and methane propellant to 200+ tons of thrust is quite literally staged, meaning that the ignition doesn’t happen all at once. Rather, the preburners – essentially their own, unique combustion chambers – ignite an oxygen- or methane-rich mixture, the burning of which produces the gas and pressure that powers the turbines that bring fuel into the main combustion chamber. That fuel then ignites, producing thrust as they exit the engine’s bell-shaped nozzle.

The first obvious test occurred around 7:30pm CT, July 14th. (LabPadre)
The second obvious test followed around 8:50 pm CT. (LabPadre)

Although the fireworks are so subtle that they are easily missed, the conditions inside the preburner – hidden away from view – are actually far more intense than the iconic blue, purple, and pink flame that exists Raptor’s nozzle. This is because the preburners have to nurture the conditions necessary for the pumps they power to fuel the main combustion chamber. Much like hot water will cool while traveling through pipes, the superheated gaseous propellant that Raptor ignites to produce thrust will also cool (and thus lose pressure) as it travels from Raptor’s preburner to the main combustion chamber.

Thus, if the head pressure produced in the preburners is too low, Raptor’s thrust will be (roughly speaking) proportionally limited at best. At worst, low pressure in the preburners can completely prevent Raptor from starting and running stably and can even trigger a “hard start” or shutdown that could damage or destroy the engine. As such, to preburners fundamentally have to operate at higher chamber pressures (and thus higher temperatures) than the main combustion chamber (the big firey bit at the end). According to Elon Musk, Raptor’s oxygen preburner has the worst of it, operating at pressures as high or higher than 800 bar (11,600 psi, 80 megapascals).

Coincidentally, this is roughly equivalent to the pressure at the bottom of the Pacific Ocean.

Starhopper and Raptor seen on the afternoon of July 14th, preparing for an evening of testing. (NASASpaceflight – bocachicagal)

In short, preburner testing is no less critical than full-on static fire testing with an engine like Raptor. July 14th’s test was also made doubly efficient due to the fact that preburner testing requires liquid propellant, which effectively makes the whole test a wet dress rehearsal (WDR) even before any engine ignition or partial ignition is involved. Per SpaceX moving from propellant loading to preburner/turbine testing, Starhopper is almost certainly healthy and operating as expected, an excellent sign that the ungainly vessel may be ready for a static fire of Raptor as early as 2pm CT, July 15th.

The memes, oh, the memes.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Tesla’s next-gen Optimus prototype with Grok revealed

The video shows a new Optimus prototype answering questions and taking some very robotic steps, evidently revealing that the next-generation version is in its early stages of development.

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Tesla’s next-generation Optimus robot with AI assistant Grok has been revealed in a new video shared on X.

Tesla CEO Elon Musk was with Salesforce CEO Marc Benioff last night, and it appears the frontman gave Benioff an exclusive look at some upcoming technology.

Tesla talks Semi ramp, Optimus, Robotaxi rollout, FSD with Wall Street firm

The video shows a new Optimus prototype answering questions and taking some very robotic steps, evidently revealing that the next-generation version is in its early stages of development. It features Grok for some additional utility, as it answered questions Benioff asked in the short video.

Here’s what was uploaded to X:

It appears that there are several big changes to this next-generation version of Optimus, some of which have been discussed by Musk and Tesla in the past.

The first is purely cosmetic, but the gold color that Optimus is wearing in this is a new and fresh look that we have not seen before.

Perhaps the most interesting change that is evident here is the hands, which are much more detailed than past versions of Optimus:

However, we’re not too sure that these are what will be released with the next-gen Optimus, because they don’t appear to be functional, and they are more reminiscent of mannequin hands than anything.

The hands on Optimus have been a significant part of the program, as they are among the most crucial pieces of equipment on a robot. It needs to be able to perform both delicate and more imposing tasks. Tesla has aimed for Optimus to be able to thread needles or play the piano.

It was one of the most discussed improvements the company mentioned in past comments regarding how it planned to improve from Gen 2 to this next version.

Musk mentioned regarding Optimus:

“Next-generation Optimus hand, which we have in prototype form, has actuators that have moved to the forearm, just like humans, and they operate the fingers through cables, just like human hands.”

Within Optimus lies a significant opportunity for Tesla to gain considerable strength in terms of market share and valuation.

If Tesla can efficiently develop and deploy the humanoid robot over the next several years, the company stands to gain, as companies will utilize it for tasks that require tedious labor.

Musk recently said Optimus will be a major contributor to Tesla’s valuation moving forward. He believes it will make up roughly 80 percent of the company’s value.

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Tesla CEO Elon Musk to provide more details for Master Plan Part IV

Musk stated that he would be adding specifics to the plan in a later update.

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Credit: xAI/X

Tesla CEO Elon Musk will be adding more specifics to the recently-released Master Plan Part IV. Musk shared the update on social media platform X amidst conversations about the general nature of the Master Plan Part IV. 

In a conversation on X, Musk responded to a post from Tesla retail shareholder and bull Dave Lee, who observed that the currently released Master Plan Part IV could really just be the introduction to the real plan due to its absence of specifics.

Elon Musk responded, stating that he would be adding specifics to the plan in a later update. “Fair enough. Will add more specifics,” Musk wrote in his post.

Tesla has been following Elon Musk’s Master Plans for decades. The first Master Plan, released in 2006, outlined the company’s path from the original Tesla Roadster to the Model 3, as well as the first steps for Tesla Energy. Master Plan Part Deux, released in 2016, covered the ramp of Tesla Energy, the expansion of Tesla’s vehicle lineup, and the rollout of a Robotaxi service.

Master Plan Part 3 was more ambitious as it was generally an in-depth proposal for achieving a global sustainable entry economy by transitioning to electricity-powered vehicles, homes, and industry, which will, in turn, be powered by renewable energy sources like solar and wind. Master Plan Part 3 also included a five-step plan to accomplish this, allowing the world to transition to a fully electrified future. 

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Master Plan Part IV, which was released a few days ago, focused on automation and artificial intelligence to achieve sustainable abundance. But while the first two Master Plans were very clear and specific and Master Plan Part 3 was very in-depth, Master Plan Part IV was quite general and vague in comparison. It was easy to tell that Optimus would play a big role in the pursuit of sustainable abundance, but apart from that, there were no specifics as to how Tesla intended to achieve its goals.

Fortunately, these specifics would be discussed by Musk in a later update to the plan.

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Tesla just had its best wholesale month this year in China

Tesla China’s wholesale figures include both vehicles that are sold domestically and exported abroad.

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Credit: Tesla China

Tesla China just had its best wholesale month this 2025 so far. In August, the electric vehicle maker sold 83,192 vehicles wholesale, a 22.55% increase compared to July 2025’s 67,886 units.

Tesla China’s wholesale figures are still down year-over-year, but the company’s momentum seems notable, especially with the arrival of the Model Y L.

August 2025 figures

As noted in a CNEV Post report, August 2025’s 83,192 wholesale figures are 4.04% less than the 86,697 units that were sold in the same period last year. It is, however, a 22.55% improvement from the previous month. From January to August, Tesla China sold 515,552 units wholesale, a 12.24% year-over-year decrease. 

It should be noted that Tesla China’s wholesale figures include both vehicles that are sold domestically and exported abroad. With this in mind, August’s results bode well for Tesla China, as it suggests that Gigafactory Shanghai is now hitting its pace with both its domestic deliveries and its exports. Giga Shanghai serves as Tesla’s primary vehicle export hub.

Model Y L factor

Tesla had a challenging first quarter this year, thanks in part to the changeover to the Model Y across the Fremont factory, Giga Texas, Giga Shanghai, and Giga Berlin-Brandenburg. This changeover resulted in low sales in the first quarter. Political controversies surrounding Elon Musk and violence against Tesla stores and vehicles in the first and second quarters in the United States and Europe did not help much either.

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This Q3, however, Tesla seems to be hitting its stride, especially in China. The launch of the new Model Y L has allowed Tesla to compete in the six-seat, large SUV segment, a market that was previously closed to the standard Model Y. Reports have suggested that Tesla China has been seeing a lot of demand for the Model Y L, which should help the company achieve higher sales this quarter and the remaining months of the year.

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