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SpaceX wiggles Starhopper’s Raptor engine, tests parts ahead of hover test debut
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.
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.
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.
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.
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Morgan Stanley’s Adam Jonas dubs Tesla FSD a “game changer” after marathon drive
Jonas reported that FSD handled more than 99% of the miles.
Morgan Stanley’s analyst Adam Jonas shared a notable endorsement of Tesla’s Full Self-Driving (FSD) software after completing a 1,400-mile round trip from New York to Michigan in his Model Y.
Jonas reported that FSD handled more than 99% of the miles, calling the system “a game changer” for long-distance driving.
Hands-free experience
Jonas drove his 2021 Tesla Model Y equipped with Hardware 3 and FSD Supervised v12.6.4, and he used the system nearly the entire trip. “Having your hands off the wheel and feet off the pedals for nearly 12 hours of driving is a real game changer that is hard to appreciate without experiencing it for yourself,” he noted.
He explained that outside of two heavy downpours, one on the Pennsylvania Turnpike and another in suburban Detroit, plus some light maneuvering in fast food parking lots, FSD handled the drive without any human intervention. “FSD made no mistakes or close calls that I recall. The system handles highways very safely and confidently. I cannot imagine buying another EV without FSD.”
Broader implications
Jonas added that he has used FSD consistently over the past 18 months, and the $8,000 he paid for the feature feels like a bargain considering the value. He also praised Tesla’s Supercharging network, which supported his trip without issue.
Jonas has been one of Wall Street’s most closely followed voices on Tesla, and his comments add weight to the ongoing debate about the role of autonomy in the company’s future. His current price target for Tesla stock stands at $410. During Morgan Stanley’s 13th Annual Laguna Conference, he echoed similar experiences with Tesla’s software, emphasizing that FSD “probably drove well over 99% of the miles” on his recent trips.
Elon Musk
Elon Musk just bought $1 billion in Tesla stock, his biggest purchase ever
Prior to this latest move, Musk’s most recent purchase was for about 200,000 shares worth $10 million in 2020.
Tesla (NASDAQ:TSLA) shares rose on Monday after CEO Elon Musk disclosed a rare insider purchase of company stock worth about $1 billion.
A filing with the U.S. Securities and Exchange Commission (SEC) revealed that Musk acquired 2.57 million shares last Friday at various prices. The move represents Musk’s largest TSLA purchase ever by value, as per Verity data.
Elon Musk’s TSLA purchase
The disclosure sent Tesla shares up more than 8% in premarket trading Monday, as investors read the purchase as a notable vote of confidence, as stated in a CNBC report. Tesla stock had closed slightly lower Friday but remains more than 25% higher over the past three months. It should be noted that prior to this latest move, Musk’s most recent purchase was for about 200,000 shares worth $10 million in 2020.
Market watchers say the purchase could help shore up investor sentiment amid a volatile year for TSLA stock. Shares have faced pressure from a variety of factors, from year-over-year sales challenges due to the new Model Y changeover, political controversies tied to Musk, and reduced U.S. incentives for EVs under the Trump administration. Nevertheless, analysts such as Wedbush’s Dan Ives stated that Musk’s purchase was a “huge sign of confidence for Tesla bulls and shows Musk is doubling down on his Tesla A.I. bet.”
Tesla and Elon Musk
Musk already owns about 13% of Tesla, and his latest purchase comes as the company prepares for a key shareholder vote in November. Investors will decide whether to approve a compensation package for Musk that could ultimately be worth as much as $975 billion if ambitious market value milestones are achieved. The package has a long-term target of pushing Tesla’s market capitalization to $8.5 trillion, compared with about $1.3 trillion at Friday’s close.
Wall Street’s current consensus price target still implies a roughly 20% decline from current levels, though some Tesla bulls remain optimistic that the company could shift its focus toward autonomy, AI, and robotics. Musk has also asked shareholders to approve an investment into his latest venture, xAI.
Tesla is adjusting one key detail of Robotaxi operations in Austin: service hours.
Tesla’s Robotaxi platform in Austin has been active since late June and has been running smoothly since then. It has its limits, as Tesla has set hours that Robotaxis can operate, as well as a distinct Service Area, also known as a geofence, which has expanded three times already.
While the geofence is currently approximately 170 square miles in size, Tesla has recently enabled freeway drives, which also necessitated an adjustment to the company’s strategy with its “Safety Monitors.”
Tesla explains why Robotaxis now have safety monitors in the driver’s seat
Traditionally, they sit in the passenger’s seat. During highway driving, they move to the driver’s seat.
These are just a few adjustments that have been made over the past two and a half months. Now, Tesla is adjusting the service hours of Robotaxi operation in Austin, but only slightly.
Tesla will now operate its Robotaxi ride-hailing service from 6 a.m. to 2 a.m., extending the hours by two hours. It previously shut down at midnight.
🚨 Tesla Robotaxi operation in Austin now will end at 2 a.m., a two-hour extension from its previous end time of midnight.
Its new service hours are now 6 a.m. to 2 a.m. local time pic.twitter.com/wXdYO6ARPB
— TESLARATI (@Teslarati) September 13, 2025
Tesla has implemented a variety of safeguards to ensure riders and drivers are safe during Robotaxi rides, and they have made it a point to adjust things when they feel confident that it will not cause any issues.
Many people have been critical of Robotaxi, especially because a person sits in the front of the car.
However, an accident or some type of mistake could do more damage to the autonomous travel sector than anything else. This would not just impact Tesla, but any company operating an autonomous ride-hailing service in the country.
Morgan Stanley’s Adam Jonas dubs Tesla FSD a “game changer” after marathon drive
Elon Musk just bought $1 billion in Tesla stock, his biggest purchase ever
Tesla adjusts one key detail of Robotaxi operations in Austin
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