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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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Elon Musk

Elon Musk announces disappointing Tesla Optimus update

In a post on X on March 31, Musk stated that Optimus 3 is mobile but requires some finishing touches before it is ready to be shown to the world. This update comes on the final day of the first quarter, a period when Tesla had previously signaled expectations for a Gen 3 reveal.

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Credit: Tesla China

Elon Musk announced a disappointing update to the unveiling of Tesla Optimus and its third-generation iteration, missing a timeline it aimed to hit in the first quarter of the year.

Musk has confirmed that the highly anticipated Optimus Gen 3 humanoid robot is already walking around and operational, yet the public unveiling will face a short delay as the company applies final refinements.

In a post on X on March 31, Musk stated that Optimus 3 is mobile but requires some finishing touches before it is ready to be shown to the world. This update comes on the final day of the first quarter, a period when Tesla had previously signaled expectations for a Gen 3 reveal.

The announcement follows reports of Optimus Gen 3 appearing at the Tesla Diner in Los Angeles, where it was observed serving and moving about until sunset. Images and videos shared by observers captured the robot in action, highlighting its progress in real-world mobility.

Tesla had aimed to showcase the production intent version of Optimus Gen 3 during the first quarter of 2026, positioning it as a major step toward factory deployment and eventual commercial availability. Musk has described the robot as featuring advanced capabilities, including highly dexterous hands with significant degrees of freedom, powered by Tesla’s AI systems for complex tasks.

This minor postponement aligns with Tesla’s iterative approach to development. Earlier statements from Musk indicated that Gen 3 would represent the most advanced humanoid robot yet, designed primarily for internal factory use before scaling to external customers.

Elon Musk’s $10 Trillion robot: Inside Tesla’s push to mass produce Optimus

Production timelines point toward low-volume output starting in the summer of 2026, with volume ramp-up targeted for 2027. The delay underscores the company’s commitment to quality over speed, ensuring the robot meets rigorous standards for safety and performance in practical environments.

Optimus represents a cornerstone of Tesla’s long-term vision beyond electric vehicles. Musk has repeatedly emphasized that successful humanoid robotics could transform industries by addressing labor shortages and enabling new forms of productivity.

Competitors in the space continue to advance their own platforms, yet Tesla’s vertical integration, from custom actuators to end-to-end AI training, positions Optimus as a potential leader. Community reactions on social media range from excitement over visible progress to impatience with shifting timelines, a familiar pattern in Tesla’s innovation journey.

Investors and enthusiasts view Optimus as critical to Tesla’s valuation, potentially surpassing its automotive business in scale. With the robot already demonstrating walking and basic interactions, the finishing touches likely involve software polishing, hardware fine-tuning, and reliability enhancements.

Musk’s update suggests the reveal could arrive in the coming weeks or months, maintaining momentum toward broader deployment.

As Tesla pushes the boundaries of physical artificial intelligence, this latest development keeps Optimus in the spotlight. The company continues to prioritize rapid iteration while delivering on its promises to shareholders and customers. The robotics revolution at Tesla appears closer than ever, promising profound impacts on manufacturing, services, and daily life in the years ahead.

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Elon Musk

Countdown: America is going back to the Moon and SpaceX holds the key to what comes after

NASA’s Artemis II launches Wednesday, sending humans near the Moon for the first time since 1972.

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For the first time since Apollo 17 touched down on the lunar surface in December 1972, the United States is sending humans back toward the Moon. NASA’s Artemis II mission is set to launch as early as this week from Kennedy Space Center in Florida, carrying four astronauts on a 10-day journey around the Moon and back to Earth. It will not land anyone on the surface this time, but it is the first crewed flight in over half a century to travel beyond low Earth orbit, and it sets the stage for Elon Musk’s SpaceX missions to follow.

The mission uses NASA’s Space Launch System rocket and the Orion spacecraft, which will fly around the Moon before splashing down in the Pacific Ocean around April 10. For context, an uncrewed Artemis I flew the same path in 2022, proving the hardware worked. Artemis II now tests it with people aboard.

According to NASA’s official countdown blog, launch preparations are on track with an 80 percent chance of favorable weather. “Hey, let’s go to the moon!” Commander Wiseman told reporters upon arriving at Kennedy Space Center.

Source: NASA

Beyond Artemis II lies the lander question, and that is where SpaceX enters directly. In 2021, NASA awarded SpaceX a $2.89 billion contract to develop the Starship Human Landing System, a modified version of Starship designed to ferry astronauts from lunar orbit to the surface. The original plan called for SpaceX to deliver that lander for Artemis III, which was to be the first crewed lunar landing. Timing for Starship development, however, caused NASA to restructure the mission sequence entirely.

Before SpaceX’s Starship Human Landing System (HLS) can put anyone on the Moon, it has to solve a problem no rocket has demonstrated at scale, which is refueling in orbit. Because the Starship HLS requires approximately ten tanker launches worth of propellant loaded into a depot in low Earth orbit before it has enough fuel to reach the lunar surface, SpaceX plans to conduct this refueling process using its upgraded V3 Starship. And until that demonstration flies and succeeds, the Starship moon lander remains a question mark.

SpaceX’s Starship V3 is almost ready and it will change space travel forever

In February 2026, NASA Administrator Jared Isaacman confirmed that Artemis III, now planned for mid-2027, and will instead test lunar landers in low Earth orbit, with the actual landing pushed to Artemis IV that’s targeted for 2028.

Musk responded to earlier criticism of SpaceX’s schedule by posting on X that his company is “moving like lightning compared to the rest of the space industry,” and added that “Starship will end up doing the whole Moon mission.” The contract competition was also reopened in October 2025 by then NASA chief Sean Duffy, who cited Starship’s delays and said the agency needed speed given China’s own stated goal of landing astronauts on the Moon by 2030.


Artemis came from the first Trump administration’s 2017 Space Policy Directive 1, which directed NASA to return humans to the Moon. The program picked up pace through the 2020s, with the Orion spacecraft and SLS taking years to develop at enormous costs. SpaceX entered the picture in 2021 as the chosen lander contractor, tying the commercial space sector into what had historically been an all government undertaking.

Whether SpaceX’s Starship ultimately carries astronauts to the lunar surface or shares that role with Blue Origin’s competing lander, this week’s Artemis II launch is the necessary first step. Getting four humans to the Moon’s vicinity and back safely is the proof of concept everything else depends on.

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Elon Musk

Elon Musk debunks latest rumors about SpaceX IPO

Musk has swiftly put to rest circulating reports suggesting that SpaceX would exclude popular retail brokerages Robinhood and SoFi from its highly anticipated initial public offering. In a direct response posted on X on March 31, Musk stated simply, “These reports are false,” addressing widespread speculation fueled by a Reuters article.

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(Credit: SpaceX)

Tesla and SpaceX CEO Elon Musk debunked the latest rumors about the space exploration company’s initial public offering (IPO), which has been the subject of a wide array of speculation over the last few weeks.

With SpaceX likely heading to Wall Street to become a publicly-traded stock in the coming months, there is a lot of speculation surrounding how it will happen, whether the company will potentially combine with Tesla, and more.

Tesla and SpaceX to merge in 2027, Wall Street analyst predicts

But the latest rumors have to do with where SpaceX will list the stock.

Musk has swiftly put to rest circulating reports suggesting that SpaceX would exclude popular retail brokerages Robinhood and SoFi from its highly anticipated initial public offering.

In a direct response posted on X on March 31, Musk stated simply, “These reports are false,” addressing widespread speculation fueled by a Reuters article.

The Reuters report, published March 30, claimed that Morgan Stanley’s E*Trade was in talks to lead the sale of SpaceX shares to small U.S. investors.

Sources indicated that Robinhood and SoFi, despite pitching for roles, faced potential exclusion from the retail allocation, with Fidelity also competing for a piece of the action. The story quickly spread across financial media, raising concerns among retail investors eager to participate in what could be one of the largest IPOs in history.

SpaceX has a reported valuation nearing $1.75 trillion, and Musk’s plan to allocate up to 30 percent of shares to individual investors — far above the typical 5-10% — had generated massive excitement.

Musk’s concise denial immediately calmed the narrative. The original X post quoting the rumor garnered significant engagement, with users expressing relief that everyday investors would not be sidelined.

This episode reflects Musk’s hands-on approach to SpaceX’s public debut.

Earlier reporting revealed plans for an unusually large retail slice to leverage Musk’s dedicated fan base and stabilize post-IPO trading. SpaceX aims to file potentially as early as this period, building on momentum from its Starship program and Starlink growth.

The IPO could mark a transformative moment, potentially elevating Musk’s status further while democratizing access to a company long reserved for accredited investors and institutions.

The rumor’s quick debunking also revives debates about retail access in high-profile listings. Robinhood gained popularity during the 2021 meme-stock surge but faced criticism for past trading restrictions.

SoFi has positioned itself as a modern financial platform for younger investors. Excluding them could have limited participation from tech-savvy retail traders who form a core part of Musk’s supporter base across Tesla and SpaceX.

While details remain fluid, Musk’s intervention reinforces commitment to broad accessibility. As preparations advance, investors await official filings. For now, the message is clear: rumors of restricted retail access were overstated, keeping the door open for widespread participation in SpaceX’s public chapter.

This development comes amid broader market enthusiasm for space and technology stocks. Musk’s transparency through X continues to shape public perception, distinguishing SpaceX’s path from traditional Wall Street norms. With retail allocation potentially reaching 30 percent, the IPO promises to be both commercially massive and culturally significant.

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