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SpaceX CEO Elon Musk says major Starship engine bug is fixed as Raptor testing continues

Starhopper awaits its first truly flightworthy Raptor as CEO Elon Musk says SpaceX may have solved the technical bug delaying hop tests. (NASASpaceflight - bocachicagal, SpaceX)

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SpaceX CEO Elon Musk has revealed the latest official photo of the company’s Raptor engine in action and indicated that a major technical issue with vibration appears to have been solved, hopefully paving the way for Starhopper’s first untethered flights.

Partly due to Musk’s own involvement in the program, SpaceX’s propulsion development team have struggled to get any single Raptor engine to survive more than 50-100 seconds of cumulative test fires. According to information from sources familiar with the program, Musk has enforced an exceptionally hardware-rich development program for the first full-scale Raptor engines to such an extent that several have been destroyed so completely that they could barely be used to inform design optimization work. Although likely more strenuous and inefficient than it needed to be, the exceptionally hardware-rich test program appears to have begun to show fruit, with the sixth engine built (SN06) passing its first tests without exhibiting signs of a problem that has plagued most of the five Raptors that came before it.

Resonance: not even once

In his tweet, Musk cryptically noted that a “600 Hz Raptor vibration problem” appears to have been fixed as of SN06’s first few static fire tests since arriving in McGregor, Texas. More likely than not, the self-taught SpaceX executive is referring to the hell that is mechanical resonance in complex machines and structures. Shown below, the Tacoma Narrows Bridge’s 1940 collapse – quite possibly the single most famous civil engineering failure of all time – is an iconic example of the unintuitive power of resonance in complex systems.

An excellent overview of the challenges and fairly young history of mechanical resonance in modern engineering.

When it was inaugurated, the first Tacoma Narrows Bridge was one of the longest suspension bridges ever built and implemented new techniques and technologies that had never been tried at such a large scale. As Grady (Practical Engineer) aptly notes, mechanical resonance – in this case, triggered by consistent winds running through the Puget Sound – simply wasn’t something that period engineers knew they had to worry about. When rapidly pushing the envelope of engineering and construction, the chances of discovering entirely novel failure modes also increases – it’s simply one of the costs of extreme innovation.

The first finalized Raptor engine (SN01) completed a successful static fire debut on the evening of February 3rd. (SpaceX)
Just five days after its first ignition, SpaceX successfully tested Raptor SN01 at more than twice the thrust of Merlin 1D. (SpaceX)
The latest official photo of Raptor testing in McGregor. This engine is likely SN06, the sixth Raptor produced in 2019. (SpaceX/Elon Musk)

Luckily for SpaceX, the company doesn’t have to clash with the immense challenge of testing something as large, complex, and expensive as a suspension bridge. Raptor, Starship, and Super Heavy need not necessarily be perfect on SpaceX’s first try, whereas civil bridges must essentially be flawless on the first try, despite being one of a kind. This is why SpaceX has been chewing through an average of one Raptor engine per month since February 2019 – by testing engines to destruction and aggressively comparing engineering expectations with observed behavior and post-test hardware conditions, rapid progress can (theoretically) be made.

Instead of spending another year or more analyzing models and testing subscale engines and components, SpaceX dove into integrated testing of a sort of minimum-viable-product Raptor design, accepting that the path to a flightworthy, finalized design would likely be paved with one or several dozen destroyed engines. According to Musk, the biggest pressing design deficiency involved a mode of mechanical resonance that may or may not have been predicted over the course of the design process. Dealing with unprecedented conditions, it’s not particularly surprising that some sort of new resonance mode was discovered in Raptor.

For the time being, SpaceX continues to work around the clock to build its first two orbital Starship prototypes (one in Texas, one in Florida), while also outfitting Starhopper and completing any possible engine-less tests in anticipation of the first flightworthy Raptor’s arrival. If Musk’s early analysis proves correct and Raptor SN06 makes it through lengthier static fire tests unscathed over the next week or so, the engine could potentially be delivered to Boca Chica as early as mid-July.

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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 Roadster appearance at SpaceX has merger watchers talking

Tesla’s next generation Roadster was spotted at SpaceX’s Hawthorne headquarters, two weeks after its unveiling.

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The Roadster’s rear wing, one of the aerodynamic elements Tesla pairs with a fan-based downforce system. (Image: Tesla)

Tesla’s next generation Roadster turned up at SpaceX’s headquarters in Hawthorne, California on Wednesday, less than two weeks after the car flew off a ramp at its unveiling in Texas.

Photos shared on X by SpaceX Engineer (@DeannaRiceSPCX) show the new Roadster parked outdoors beside the famed Falcon 9 that stands outside company headquarters at the corner of Crenshaw Boulevard and Jack Northrop Avenue. Rocket B1019 was the first orbital-class booster ever to land after a launch on December 21, 2015 after it sent 11 Orbcomm satellites to orbit and then flew back to Landing Zone 1 at Cape Canaveral, which would be the first landing in what became SpaceX’s reusable rocket program. SpaceX chose not to fly it again. After a test fire in Florida, the booster was shipped to Hawthorne and raised upright as a permanent monument in August 2016, as Teslarati reported at the time. Putting the Roadster, which flies on SpaceX cold gas thrusters, next to the rocket that started SpaceX’s landings is symbolic in itself.

The Thrust and Rocket versions of the Roadster use cold gas thrusters fed by composite overwrapped pressure vessels, the same type of tank SpaceX flies on Falcon 9, and Elon Musk described the car as the work of Tesla and SpaceX engineers working together. Tesla lists 0 to 60 mph in under 0.9 seconds for Thrust and under 0.59 seconds for Rocket, while the base Performance model relies on a fan and ground sealing system for grip, as Teslarati detailed in its breakdown of the three Roadster configurations.

Tesla has kept the car in the spotlight since the October 15 event near Waco. Last week, the company posted a video of the Roadster’s fighter jet inspired cockpit, including a Track Mode screen with a “Thruster · 5,500 PSI” readout, which we covered in our look at the Roadster’s center display. Musk also said owners will be able to ask the car to perform the stunts autonomously, and promised a looping track at Tesla’s Texas headquarters.

The visit comes as special committees at Tesla and SpaceX weigh a possible merger, a step Musk confirmed on SpaceX’s third quarter earnings call. The Roadster, built on SpaceX hardware, has become one of the clearest examples of the two companies already building products together.

Musk said at the unveiling that Roadster production will begin in 2028. Reservations are open with a $50,000 payment, Thrust is listed as a limited release and Rocket is invite only. Tesla says the car is not approved for public road use.

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Verizon, AT&T and T-Mobile are trying to shut Starlink out before FCC vote

AT&T, Verizon and T-Mobile want 290 MHz cut from an FCC satellite plan before Thursday.

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Starlink D2D direct to device vs Verizon, AT&T (Concept render by Grok)

AT&T, Verizon and T-Mobile are asking the Federal Communications Commission to pull nearly 300 MHz of spectrum out of a proposal that would let satellite companies like SpaceX offer cell service directly to ordinary phones. The request lands one day before the agency votes on it.

The FCC will vote Thursday, October 29, on a notice of proposed rulemaking that would make an additional 482 MHz available for direct to device service, expanding the number of eligible bands from five to 13, according to the FCC fact sheet. It would also scrap the rule requiring a satellite operator to lease spectrum from carriers, replacing it with a certification that the operator has coexistence agreements in place or holds the terrestrial license itself.

That second path matters for SpaceX. As Teslarati reported earlier this month, SpaceX agreed to buy Grain Management’s nationwide 800 MHz portfolio to turn Starlink Mobile into a full US carrier, adding to the spectrum it already bought from EchoStar.

The carriers want two bands removed, 2.5 GHz and 3.45 GHz, which make up 290 MHz of the 482 MHz on the table. Through industry group CTIA, they argued that about 300 million users depend on those bands and that satellite operations in them are not technically feasible. T-Mobile, which calls 2.5 GHz the foundation of its Ultra Capacity 5G network, said in its own filing that satellite interference could wipe out up to 96% of a cell site’s uplink coverage area and cut uplink speeds by 88% to 99%.

Executives from all three carriers met with FCC staff on October 20, and T-Mobile CEO Srini Gopalan met separately with FCC Chairman Brendan Carr. T-Mobile’s role stands out because it is still SpaceX’s US launch partner for Starlink Mobile. The three carriers have also teamed up on their own satellite joint venture to pool spectrum, a move widely seen as a response to Starlink.

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SpaceX is asking for the opposite. In an October 23 filing after meetings with FCC staff and commissioners’ offices, the company asked regulators to add the 902 to 928 MHz band to the proposal. “Doing so now saves time later,” SpaceX wrote. The company also asked the FCC to modernize interference rules and align satellite deployment requirements with those for terrestrial cell networks, saying the goal is to let satellite and ground networks work together so Americans stay connected wherever they are.

The carriers have not been shy about how they view SpaceX as a competitor. On Verizon’s third quarter earnings call Monday, its chief executive said Starlink Mobile “just can’t compete with a terrestrial network” and estimated SpaceX would need four to six years and $300 billion to $500 billion to build a full US carrier network.

Thursday’s vote will not settle which bands survive. Adopting the notice opens a public comment period, with final rules to come later in the proceeding. The FCC already considered and rejected 2.5 GHz for satellite coverage once, in 2024. SpaceX also is not the only satellite player watching: the FCC approved Amazon’s $11.6 billion acquisition of Globalstar on October 27, giving its planned direct to device fleet its own mobile satellite spectrum.

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Tesla Semi catches fire in California: what we know

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Credit: KTVU

A Tesla Semi caught fire in Hayward, California, which caused both directions of traffic to shut down for hours before being completely reopened early on Wednesday, the California Highway Patrol said.

The fire occurred just after 5:30 local time in Hayward on Tuesday, as the Semi caught fire in the southbound lanes of I-880 before CHP officials made the decision to shut down both lanes of traffic due to potential risks from hazardous chemical smoke.

There were no injuries reported.

The cause of the fire is currently unknown, as neither Tesla nor the CHP have not determined a cause.

However, some images taken before the Semi was completely destroyed by the fire seem to indicate this might have been an older unit, as it appears to be one of the designs that Tesla shipped as part of its pilot program, before revising it and starting mass production just a month ago.

At the time of publication, CHP had not returned our request for a comment for additional details, including the Semi involved and any potential collaboration on an investigation between the CHP and Tesla. We will update this story when we hear back from them.

The southbound lanes were reopened at 3:30 a.m. on Wednesday, with the northbound lanes opening last night a few hours after the fire began. The CHP did state that the lithium batteries were “incredibly difficult to extinguish,” according to NBC Bay Area.

The truck’s driver said that the Semi caught fire, but he did not have an explanation.

An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year.

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