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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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SpaceX just cleared a key FCC hurdle in its fight with Verizon and AT&T

The FCC accepted SpaceX’s bid for Grain’s 800 MHz spectrum, opening review for Starlink Mobile.

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A hand holds a smartphone displaying the Starlink Mobile app interface showing a strong “Connected – Direct to Cell” signal, with a Starlink satellite beaming connectivity signals down to Earth from orbit. The background features the planet’s night side glowing with city lights against the curve of the atmosphere, set above a scenic twilight landscape.

The Federal Communications Commission has formally opened its review of SpaceX’s plan to buy a nationwide block of 800 MHz spectrum from Grain Management, moving Starlink Mobile one step closer to operating as a full U.S. wireless carrier.

In a public notice issued Tuesday, the FCC’s Wireless Telecommunications Bureau said it accepted for filing the applications to transfer control of two Grain license companies, Prism License Co. 1 and Prism License Co. 2, to Starlink Spectrum Holdings, a wholly owned SpaceX subsidiary. The deal covers 546 paired licenses across 3,224 counties, reaching roughly 100% of the U.S. population in all 50 states, Washington, D.C., Puerto Rico and the U.S. Virgin Islands. The proceeding sits under WT Docket No. 26-313.

Acceptance is not approval. It means the applications cleared an initial review and the public comment window is now open. Comments and petitions to deny are due December 1, and oppositions are due December 8. The bureau also said the conditions attached to Grain’s July purchase of the licenses from T-Mobile, which require rapid buildout for terrestrial and direct to device service, would carry over to SpaceX if the transfer is approved.

SpaceX announced the agreement on October 8, saying the new airwaves would let Starlink Mobile’s signal reach phones inside buildings, something its 2 GHz spectrum from EchoStar cannot do as well. The portfolio includes up to 14 MHz of paired spectrum in the 817 to 824 MHz and 862 to 869 MHz bands, which most existing phones already support. Elon Musk called it “the last critical piece of the spectrum puzzle needed for SpaceX to provide complete phone coverage in America.”

According to the filing, SpaceX would hold up to 89 MHz of total spectrum in any given market after the deal closes, including up to 14 MHz below 1 GHz. That is far under the 385 MHz threshold the FCC uses to flag a transaction for closer competitive scrutiny, and well short of the roughly 300 MHz each of AT&T, Verizon and T-Mobile holds.

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Tuesday’s notice does not decide how SpaceX can use the spectrum from orbit. A separate application SpaceX filed on October 27 seeking authority to provide supplemental coverage from space on the same frequencies, along with related waiver requests, is still pending before the commission.

The ground network is already taking shape. Last week, SpaceX picked Qualcomm to supply radios, baseband units and software for a nationwide 5G build, with deployment across tens of thousands of U.S. cell sites starting in 2027. The FCC also voted on October 29 to advance a proposal opening another 482 MHz to direct to device service, though AT&T, Verizon and T-Mobile hacritive pushed to strip nearly 300 MHz from it. SpaceX President Gwynne Shotwell has said service on SpaceX’s own airwaves is targeted for early 2028.

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Tesla upfitter offers to keep Cybertruck alive

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Credit: Unplugged Performance

A Tesla upfitter has offered to take over Cybertruck lines from the company in a last-ditch effort to save the all-electric pickup from being completely canceled in the middle of 2027.

Unplugged Performance, the Hawthorne, California-based Tesla aftermarket specialist, has publicly offered to take over Cybertruck production from Tesla, funding the effort “through a consortium of investors.”

The proposal comes as Tesla prioritizes its Cybercab Robotaxi program and prepares to wind down Cybertruck assembly at Gigafactory Texas around mid-2027.

Founded in 2013 by Ben Schaffer and located adjacent to Tesla’s Design Studio and SpaceX, Unplugged Performance has become a leading provider of premium upgrades for Tesla vehicles, including extensive Cybertruck packages under its UP INVINCIBLE line.

Through its UP.FIT division, the company has also developed purpose-built police and fleet versions of the Cybertruck, including deliveries to agencies such as the Las Vegas Metropolitan Police Department.

In an X post on Tuesday, Unplugged said:

“An open offer to Tesla: We fully support putting Cybercab first, and we’d be glad to take the Cybertruck line off your hands. We’d fund it with a consortium of investors and run it at no cost to Tesla’s floor space, headcount, or focus. All of that goes to Cybercab. Cybercab gets first call on battery cells too. We’ll wait our turn. Tesla gains incremental profit: a license fee, plus FSD and Robotaxi network revenues on every vehicle built. We’d build the Cybertruck, a three-row CyberSUV, and an unmanned CyberCargo hauler. More autonomous miles, across every surface of this planet and beyond. Worth a conversation?”

The arrangement would free Tesla resources and manufacturing capacity for Cybercab while allowing continued production of the stainless-steel pickup and expanded variants. Unplugged Performance indicated it would wait for battery cells after Cybercab needs are met and would generate ongoing revenue for Tesla through licensing and software/network services on the vehicles it produces.

Following strong initial interest, Unplugged Performance posted a follow-up inviting potential investors and strategic partners to email cyber@unpluggedperformance.com. The company clarified that the outreach is solely to gauge interest and does not constitute an offer to sell securities or acceptance of funds at this stage.

The proposal arrives shortly after Elon Musk indicated that Cybertruck production in Texas would be phased out by roughly the middle of 2027 to expand Cybercab output.

Whether Tesla engages with the offer remains to be seen, but the public overture highlights both the aftermarket specialist’s deep experience with the Cybertruck platform and the growing focus on autonomy within Tesla’s manufacturing plans.

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Elon Musk

Elon Musk says Tesla Cybercab future is ‘obvious to anyone with eyes and a brain’

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Elon Musk said the Tesla Cybercab will perform “a majority of all passenger miles” where it is allowed to operate and that point is “obvious to anyone with eyes and a brain.”

Musk used the point to double down on the company’s decision to ax the cult-favorite Cybertruck, as its production space will be removed and transitioned into additional Cybercab lines. The move has catalyzed a polarizing conversation on whether its right or wrong.

Whatever side you are on — it’s happening.

Regardless, Musk seems to be getting to the point that he is done talking about the choice. At some point, you have to think that this was truly a difficult decision for him and the company as well, and this is not something he took lightly. In fact, he’s probably a little bit disappointed with it, too.

But the point remains that the Cybertruck is gone. Musk’s focus is purely on developing an autonomous platform that the world will utilize for transportation, and he’s telling you that anyone “with eyes and a brain” can see it:

Tesla is betting that all of its passengers in the future will be okay with not owning their own personal cars and will be fine with ride-hailing for the rest of their lives. Every dinner, every errand, every trip to the airport and transportation thereafter, will all be operated by ride-sharing, and in Tesla’s perfect world, it will happen in a Cybercab.

As of now, Cybercab is only active in Austin, but it has been spotted all over the country with a driver behind the wheel in those prototypes. In Austin, the car has no steering wheel or pedals for people to control the vehicle.

The Cybertruck dilemma is one that has truly come across the entire Tesla community and while it seems to be a great idea to keep it because people love it, the business side of things is steering Musk and Tesla in another direction.

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