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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 removes Safety Monitors, begins fully autonomous Robotaxi testing

This development, in terms of the Robotaxi program, is massive. Tesla has been working incredibly hard to expand its fleet of Robotaxi vehicles to accommodate the considerable demand it has experienced for the platform.

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12 hours ago

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December 14, 2025

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Credit: @Mandablorian | X

Tesla has started Robotaxi testing in Austin, Texas, without any vehicle occupants, the company’s CEO Elon Musk confirmed on Sunday. Two Tesla Model Y Robotaxi units were spotted in Austin traveling on public roads with nobody in the car.

The testing phase begins just a week after Musk confirmed that Tesla would be removing Safety Monitors from its vehicles “within the next three weeks.” Tesla has been working to initiate driverless rides by the end of the year since the Robotaxi fleet was launched back in June.

Two units were spotted, with the first being seen from the side and clearly showing no human beings inside the cabin of the Model Y Robotaxi:

Another unit, which is the same color but was confirmed as a different vehicle, was spotted just a few moments later:

The two units are traveling in the general vicinity of the South Congress and Dawson neighborhoods of downtown Austin. These are located on the southside of the city.

This development, in terms of the Robotaxi program, is massive. Tesla has been working incredibly hard to expand its fleet of Robotaxi vehicles to accommodate the considerable demand it has experienced for the platform.

However, the main focus of the Robotaxi program since its launch in the Summer was to remove Safety Monitors and initiate completely driverless rides. This effort is close to becoming a reality, and the efforts of the company are coming to fruition.

It is a drastic step in the company’s trek for self-driving technology, as it plans to expand it to passenger vehicles in the coming years. Tesla owners have plenty of experience with the Full Self-Driving suite, which is not fully autonomous, but is consistently ranked among the best-performing platforms in the world.

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Tesla refines Full Self-Driving, latest update impresses where it last came up short

We were able to go out and test it pretty extensively on Saturday, and the changes Tesla made from the previous version were incredibly impressive, especially considering it seemed to excel where it last came up short.

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23 hours ago

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December 14, 2025

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Credit: TESLARATI

Tesla released Full Self-Driving v14.2.1.25 on Friday night to Early Access Program (EAP) members. It came as a surprise, as it was paired with the release of the Holiday Update.

We were able to go out and test it pretty extensively on Saturday, and the changes Tesla made from the previous version were incredibly impressive, especially considering it seemed to excel where it last came up short.

Tesla supplements Holiday Update by sneaking in new Full Self-Driving version

With Tesla Full Self-Driving v14.2.1, there were some serious regressions. Speed Profiles were overtinkered with, causing some modes to behave in a strange manner. Hurry Mode was the most evident, as it refused to go more than 10 MPH over the speed limit on freeways.

It would routinely hold up traffic at this speed, and flipping it into Mad Max mode was sort of over the top. Hurry is what I use most frequently, and it had become somewhat unusable with v14.2.1.

It seemed as if Speed Profiles should be more associated with both passing and lane-changing frequency. Capping speeds does not help as it can impede the flow of traffic. When FSD travels at the speed of other traffic, it is much more effective and less disruptive.

With v14.2.1.25, there were three noticeable changes that improved its performance significantly: Speed Profile refinements, lane change confidence, and Speed Limit recognition.

Speed Profile Refinement

Speed Profiles have been significantly improved. Hurry Mode is no longer capped at 10 MPH over the speed limit and now travels with the flow of traffic. This is much more comfortable during highway operation, and I was not required to intervene at any point.

With v14.2.1, I was sometimes assisting it with lane changes, and felt it was in the wrong place at the wrong time more frequently than ever before.

However, this was one of the best-performing FSD versions in recent memory, and I really did not have any complaints on the highway. Speed, maneuvering, lane switching, routing, and aggressiveness were all perfect.

Lane Changes

v14.2.1 had a tendency to be a little more timid when changing lanes, which was sort of frustrating at times. When the car decides to change lanes and turn on its signal, it needs to pull the trigger and change lanes.

It also changed lanes at extremely unnecessary times, which was a real frustration.

There were no issues today on v14.2.1.25; lane changes were super confident, executed at the correct time, and in the correct fashion. It made good decisions on when to get into the right lane when proceeding toward its exit.

It was one of the first times in a while that I did not feel as if I needed to nudge it to change lanes. I was very impressed.

Speed Limit Recognition

So, this is a complex issue. With v14.2.1, there were many times when it would see a Speed Limit sign that was not meant for the car (one catered for tractor trailers, for example) or even a route sign, and it would incorrectly adjust the speed. It did this on the highway several times, mistaking a Route 30 sign for a 30 MPH sign, then beginning to decelerate from 55 MPH to 30 MPH on the highway.

This required an intervention. I also had an issue leaving a drive-thru Christmas lights display, where the owners of the private property had a 15 MPH sign posted nearly every 200 yards for about a mile and a half.

The car identified it as a 55 MPH sign and sped up significantly. This caused an intervention, and I had to drive manually.

It seems like FSD v14.2.1.25 is now less reliant on the signage (maybe because it was incorrectly labeling it) and more reliant on map data or the behavior of nearby traffic.

A good example was on the highway today: despite the car reading that Route 30 sign and the Speed Limit sign on the center screen reading 30 MPH, the car did not decelerate. It continued at the same speed, but I’m not sure if that’s because of traffic or map data:

A Lone Complaint

Tesla has said future updates will include parking improvements, and I’m really anxious for them, because parking is not great. I’ve had some real issues with it over the past couple of months.

Today was no different:

Full Self-Driving v14.2.1.25 is really a massive improvement over past versions, and it seems apparent that Tesla took its time with fixing the bugs, especially with highway operation on v14.2.1.

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Tesla hints at Starlink integration with recent patent

“By employing polymer blends, some examples enable RF transmission from all the modules to satellites and other communication devices both inside and outside the vehicle.”

Published

2 days ago

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December 13, 2025

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Credit: Grok

Tesla hinted at a potential Starlink internet terminal integration within its vehicles in a recent patent, which describes a vehicle roof assembly with integrated radio frequency (RF) transparency.

The patent, which is Pub. No U.S. 2025/0368267 describes a new vehicle roof that is made of RF-transparent polymer materials, allowing and “facilitating clear communication with external devices and satellites.”

Tesla believes that a new vehicle roof design, comprised of different materials than the standard metallic or glass elements used in cars today, would allow the company to integrate modern vehicular technologies, “particularly those requiring radio frequency transmission and reception.

Instead of glass or metallic materials, Tesla says vehicles may benefit from high-strength polymer blends, such as Polycarbonate, Acrylonitrile Butadiene Styrene, or Acrylonitrile Styrene Acrylate.

These materials still provide ideal strength metrics for crashworthiness, stiffness for noise, vibration, and harshness control, and are compliant with head impact regulations.

They would also enable better performance with modern technologies, like internet terminals, which need an uninterrupted signal to satellites for maximum reception. Tesla writes in the patent:

“By employing polymer blends, some examples enable RF transmission from all the modules to satellites and other communication devices both inside and outside the vehicle.”

One of the challenges Tesla seems to be aware of with this type of roof design is the fact that it will still have to enable safety and keep that at the forefront of the design. As you can see in the illustration above, Tesla plans to use four layers to increase safety and rigidity, while also combating noise and vibration.

It notes in the patent that disclosed examples still meet the safety requirements outlined in the Federal Motor Vehicle Safety Standards (FMVSS).

Starlink integrated directly into Tesla vehicles would be a considerable advantage for owners. It would come with a handful of distinct advantages.

Initially, the inclusion of Starlink would completely eliminate cellular dead zones, something that is an issue, especially in rural areas. Starlink would provide connectivity in these remote regions and would ensure uninterrupted service during road trips and off-grid adventures.

It could also be a critical addition for Robotaxi, as it is crucial to have solid and reliable connectivity for remote monitoring and fleet management.

Starlink’s growing constellation, thanks to SpaceX’s routine and frequent launch schedule, will provide secure, stable, and reliable internet connectivity for Tesla vehicles.

SpaceX reaches incredible milestone with Starlink program

Although many owners have already mounted Starlink Mini dishes under their glass roofs for a similar experience, it may be integrated directly into Teslas in the coming years, either as an upgrade or a standard feature.

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