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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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6 years ago

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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 releases cryptic teaser for something massive and it’s coming this week

On Sunday morning, Tesla released a nine-second teaser video of what appears to be either a vehicle wheel, fan, or some sort of propeller, but there are no real clues as to what it could be exactly.

Published

7 hours ago

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October 5, 2025

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Credit: Tesla

Tesla has released a cryptic teaser for something massive, and it will release details on it this week. With many different projects in the works, there is a lot of speculation going on about what it could potentially be, but we have a few ideas.

On Sunday morning, Tesla released a nine-second teaser video of what appears to be either a vehicle wheel, fan, or some sort of propeller, but there are no real clues as to what it could be exactly.

It then ends with “10/7,” meaning it will announce something on October 7, which is this Tuesday:

Given that Tesla has been working on a handful of pretty notable projects that are set for unveiling at the end of this year, and there are some clues that seem to point in their direction with this short teaser video.

There are two projects that come to mind almost immediately: the Tesla Roadster is one, and the “E41” or affordable model is the other. Here’s what we know about both:

Tesla Roadster Demo Event

Tesla said earlier this year that it would have a demo event for the Roadster to unveil some new technologies and show off what it has been working on over the past few years.

There have been a lot of crazy things in the works for the Roadster, including a SpaceX package that would use cold-gas thrusters for an insane 1.1-second 0-60 MPH acceleration rate. This package was also supposed to help it hover, something CEO Elon Musk has teased for the past few years.

The Roadster was ready for release earlier this year, but after Chief Designer Franz von Holzhausen and VP of Powertrain Lars Moravy showed Musk what they had come up with, he wanted more.

Moravy said on the Ride the Lightning podcast earlier this year:

“What we had come up with exceeded what we originally planned. So, Elon was like, ‘Wow, great. Let’s do more!'”

The Roadster event was coined as “the most epic demo,” and since it was planned for the end of 2025, it is totally feasible to believe this could be it.

Elon Musk teases Tesla’s “most epic demo” by end of year

Tesla ‘E41’ Affordable Model

Some believe the teaser could be the official launch of Tesla’s affordable model, which Musk said earlier this year is simply a stripped down Model Y.

There have been some sightings of this vehicle in the past few weeks, including one on Friday that showed the vehicle completely uncovered for the first time:

The launch of the affordable model makes sense, especially from a timing perspective. With the $7,500 EV tax credit officially coming to a close on September 30, many are wondering how Tesla will spark growth in its deliveries. A more affordable EV would be the perfect response, and it is something that Tesla has been working on for some time.

Other Potential Ideas

There are some pretty interesting ideas as to what the teaser could be apart from the Roadster or affordable model. Some believe it could be a cooling fan for a GPU cluster, which would make sense considering Tesla’s prowess in data.

Grok also made an interesting guess, stating it could be a propeller for a secret air taxi Tesla is developing. This seems sort of our of left field.

We do know Tesla hosted a handful of influencers at Gigafactory Texas this past week, so whatever the company showed them is likely what will be unveiled on Tuesday.

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Tesla Optimus is learning martial arts in new video teasing capabilities

For the past few months, Tesla has been refining its capabilities and making some serious progress on what Optimus is capable of. This morning, Musk released a new video showing Optimus learning Kung Fu, perhaps its most impressive feat yet.

Published

24 hours ago

on

October 4, 2025

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Credit: Elon Musk | X

Tesla Optimus is learning martial arts, a new video released by CEO Elon Musk shows, a crazy development and advancement in the robotics project the company has been working on for a few years.

Optimus has been a major focus of Tesla for the past several years, especially as Musk has said he believes it will be the biggest product of all time and could be the biggest contributor to the company’s valuation.

For the past few months, Tesla has been refining its capabilities and making some serious progress on what Optimus is capable of. This morning, Musk released a new video showing Optimus learning Kung Fu, perhaps its most impressive feat yet:

The video shows Optimus working with a Kung Fu teacher, known as a Shifu, going through what appears to be some sort of routine of combinations. It’s quite impressive to see the fluidity of the movements and Optimus’s ability to keep up with Shifu.

Tesla has been “working hard” to scale Optimus production, Musk said last week, a project that has obviously confronted both AI and manufacturing teams with a variety of challenges.

The plan is to have an annual production run-rate of one million units by 2030, and there were plans to build 5,000 units this year.

Elon Musk gives update on Tesla Optimus progress

Musk still believes Optimus will make up roughly 80 percent of Tesla’s value. In January, he said it would be “overwhelmingly the value of the company.”

Tesla plans to launch the Gen 3 version of Optimus soon, and although a video of a new-look prototype was released by Marc Benioff, the CEO of Salesforce, the company’s frontman stated that this was not what the next-generation prototype would look like.

Elon Musk confirms Tesla has never shown Optimus V3 design yet

This video seems to show there is still significant progress being made on the Optimus project, and it will be perhaps one of the most impressive humanoid robots available to consumers in the coming years.

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Tesla Full Self-Driving v14 gets new release date, Elon Musk details

“Last minute bug cropped up with V14. Released is pushed to Monday, but that gives us time to add a few more features.”

Published

1 day ago

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October 4, 2025

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Credit: Tesla

Tesla’s Full Self-Driving version 14 has gotten a new release date after new details from CEO Elon Musk opened up some new perspectives on the suite.

Originally slated for an “early wide release” of v14 this past week, then a launch of v14.1 and v14.2 this week and next week, respectively, delays arose after Tesla’s Autopilot team found some issues within the software.

Tesla FSD V14 set for early wide release next week: Elon Musk

Musk detailed on X this morning that a “last minute bug” appeared before release, which has now pushed FSD v14’s release back to this Monday:

Musk also said the delay would give Tesla the ability to “add a few more features,” which seems like an added advantage, although he did not provide any additional details on what these features could be.

In classic Musk fashion, he has teased the capabilities of this version of the FSD suite since it became public knowledge that Tesla was working on it. He said that it is the second most important update for the AI/Autopilot team since FSD v12.

V14 will have a parameter count that is ten times what previous iterations were, which should provide more accuracy and a more human-like operation.

Musk has said v14 “feels alive” and has used the word “sentient” to describe its performance. The goal with the new FSD rollouts is to eliminate as many interventions as possible, making it as close to human driving as possible.

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