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SpaceX delays Starhopper’s first flight a few days despite Raptor preburner test success
SpaceX has (partially) ignited Starhopper’s freshly-installed Raptor engine, successfully verifying that the engine is ready for its next major test: a full ignition and static firing. Although successful, SpaceX still has some work to do before the vehicle is ready for its first untethered flight(s).
July 15th’s progress is just the latest in a several day-series of preflight tests designed to reduce the likelihood that Starhopper is destroyed over the coming days and (hopefully) weeks. If all goes planned during the awkward Starship prototype’s first foray into hover tests, SpaceX CEO Elon Musk has stated that he will provide an official presentation updating the public on the status of the company’s ever-changing next-generation rocket.
The past week or so of Starhopper preflight testing began with Raptor serial number 6 (SN06) completing the last of a series of acceptance test fires in McGregor, Texas on June 10th. Even on its own, this was a major milestone for the new SpaceX engine: Raptor SN06 was the first of the new, full-scale engines to pass the acceptance test program with flying colors. According to Musk, for the engine to complete those tests so successfully, SpaceX had to solve a challenging bug in which some sort of mechanical resonance (i.e. vibration) damaged or destroyed Raptors SN01-05.
Hours later, the engine began a short ~450 mi (720 km) journey south to Starhopper, located in Boca Chica, Texas. The engine arrived on July 11th and was fully installed on Starhopper by the following evening (July 12th), at which point SpaceX put Starhopper and Raptor through some mild but valuable thrust vector controller (TVC) tests, wiggling the car-sized engine to ensure it can accurately steer the prototype rocket.
Around two days after the above ‘wiggle’ test was successfully completed, SpaceX moved into the next stage, partially fueling Starhopper with liquid methane and oxygen propellant and helium pressurant in what is known in rocketry as a wet dress rehearsal (WDR). The (implicitly) successful WDR was capped off with a duo of what can now safely be concluded were some sort of Raptor test preceding even pre-ignition operations. Whatever the tests were, they appear to have been completed successfully.
That appears to be the case because less than 24 hours after their completion, on July 15th, SpaceX once again began loading Starhopper with propellant and pressurant for a second round of wet testing. This time around, SpaceX got right into more critical Raptor tests once enough propellant was loaded, igniting the engine’s interwoven oxygen and methane preburners.
Previously discussed 24 hours ago in a Teslarati article focused on Raptor wiggles and other miscellaneous tests, Raptor is an extremely advanced rocket engine based on a cycle (i.e. how propellant is turned into thrust) known as full-flow staged combustion.
“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.
Unintuitively, conditions inside the preburner – hidden away from view – are actually far more intense than the iconic blue, purple, and pink flame that visibly exists Raptor’s nozzle. 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 its main combustion chamber. If the 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 trigger a “hard start” or shutdown that could destroy the engine. According to Elon Musk, Raptor’s oxygen preburner thus has the worst of it, operating at pressures as high or higher than 800 bar (11,600 psi, 80 megapascals).”
In full-flow staged combustion (FFSC), even more complexity is added as all propellant that touches the engine must necessarily end up traveling through the main combustion chamber to eke every last ounce of thrust out of the finite propellant a rocket lifts off with. As such, FFSC engines can be about as efficient as the laws of physics allow any given chemical rocket engine to be, at the cost of exceptional complexity and brutally difficult development.
Additionally, FFSC physically requires two separate preburners and then makes things even harder by making each separate preburner (methane and oxygen) depend on each other’s operation for the engine to fully ignite. This means that no individual preburner can be used to kickstart Raptor – instead, SpaceX must somehow spin the turbopumps that feed propellant into each preburner with some separate system. This is all just to emphasize the fact that Raptor’s ignition sequence is a spectacularly complex orchestra of valves, spark plugs, sensors, and magic. This is why it’s valuable for Raptor to test its preburner system independently of an actual ignition test, at least as long as the engine is still in the development stages.
According to NASASpaceflight.com managing editor Chris Bergin, what this practically translates to is a minor Starhopper hover test delay of 1-2 days, while the static fire has also been pushed roughly 24 hours from July 15th to July 16th. If that full static fire produces lots of happy data, Starhopper could be cleared for a hover test debut attempt as early as Wednesday or Thursday (July 17/18).
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A Tesla Semi was involved in a fatal collision on U.S. Highway 50 in Dayton, Nevada, on Sunday, June 28, 2026, marking the first known fatal crash involving the electric Class 8 truck. The incident occurred around 7:20 a.m. at the intersection with Traditions Parkway, approximately 40 miles east of Reno and close to Tesla’s Gigafactory Nevada.
According to the Lyon County Sheriff’s Office and the Nevada State Police Highway Patrol, a semi-truck struck two passenger vehicles stopped at a traffic signal. The truck hit the vehicles from behind. Two people were pronounced dead at the scene, and a third person suffered life-threatening injuries and was flown to a hospital, Forbes reported.
Preliminary statements gathered at the scene by the Lyon County Sheriff’s Office suggested the truck driver may have fallen asleep at the wheel. However, the Nevada Highway Patrol, which is leading the investigation, stated that the official cause has not yet been determined.
Additional information is expected to be released early the following week. The truck was seized for evidence as part of the ongoing probe.
Responders at the scene included deputies from the Lyon County Sheriff’s Office, personnel from the Nevada Highway Patrol, Central Lyon County Fire Department, and the Nevada Department of Transportation. The crash led to the temporary closure of U.S. 50 in both directions.
The Tesla Semi is Tesla’s battery-electric heavy-duty truck, produced at the nearby Gigafactory in Nevada. Authorities initially described the vehicle as a semi-truck; its make was subsequently confirmed through reporting and scene identification; an interesting bit of information here, as the Semi is not yet available publicly and many do not know that Tesla builds electric trucks.
The investigation remains active, with no further official details on contributing factors or vehicle systems released as of early July 2026.
This incident highlights ongoing scrutiny of commercial vehicle safety on Nevada highways, particularly involving fatigue. Law enforcement continues to gather evidence and witness statements.
Tesla has expanded its Robotaxi program to Miami, Florida, marking the third state the autonomous ride-hailing platform has made its way to since launching last Summer.
Tesla announced today that the Robotaxi suite would now officially launch rides in a geofence in Miami:
🚨 Tesla’s “Long Weekend” continues with a HUGE announcement regarding Robotaxi!
It’s now in Miami!
Miami joins Austin, Dallas, Houston, and the Bay Area! https://t.co/ujjYjJT3Im pic.twitter.com/yPe1ZdSQIE
— TESLARATI (@Teslarati) July 3, 2026
The first geofence in Miami covers approximately 10 to 14 square miles. The area appears to be focused on western and central Miami, including Miami International Airport (MIA). It also includes popular routes like SR 826 (Palmetto Expressway), US 41 (Tamiami Trail), and connectors such as SR 968, 953, 959, and 972.
This is Tesla’s initial Miami launch zone, smaller and more targeted than some competitors’ areas (for example, Waymo’s initial rollout was broader in eastern neighborhoods). It prioritizes high-traffic, airport-linked routes before wider expansion.
The expansion is a huge signal for Tesla that it is now operating in Florida, a heavy-traffic state with many tourist areas, including Fort Lauderdale, Palm Beach, and the Boynton area, all of which are coastal and will attract perhaps millions of tourists in any given year.
¿Qué lo que Miami?
Robotaxi now available in Miami pic.twitter.com/P1m283seZU
— Tesla Robotaxi (@robotaxi) July 3, 2026
The Tesla Robotaxi network launched last year on June 22, in Austin, Texas, beginning limited commercial operations in that city. It expanded shortly thereafter into the San Francisco Bay Area of California in late July 2025, marking entry into a second state with service covering key areas such as San Francisco, San Jose, and Berkeley.
Full commercial service was achieved in Austin by November 18, 2025, strengthening its presence within Texas before further growth.
In 2026, the network continued expanding across Texas with the addition of Dallas and Houston on April 18, significantly broadening its footprint in the state. This new launch into Miami marks Tesla entering a new state and bringing active locations to include Austin, Dallas, Houston, San Antonio in Texas, and the Bay Area in California.
These sequential expansions have steadily increased the network’s reach across major metropolitan areas in Texas, California, and Florida, focusing on scaling operations city by city and state by state since the initial Austin debut.
Tesla CEO Elon Musk has tempered expectations for the company’s humanoid robot Optimus, emphasizing that initial production will ramp up slowly despite recent progress on the manufacturing line. In a July 1 reply on X, Musk responded to optimistic community speculation by stating, “No, Optimus production will be extremely slow at first, as everything is new. This is not like making a car.”
No, Optimus production will be extremely slow at first, as everything is new. This is not like making a car.
— Elon Musk (@elonmusk) July 1, 2026
The comment came in response to a post theorizing that Tesla had accelerated Optimus V3 development and might soon unveil an impressive demonstration with multiple units already in meaningful production. Musk’s clarification highlights the fundamental differences between scaling a novel humanoid robot and Tesla’s established automotive operations, which benefit from over a century of refined supply chains, tooling, and processes.
Recent updates show tangible advancement. Musk shared a photo of himself walking the Optimus production line at Fremont, where Tesla is converting former Model S/X manufacturing space. According to Q1 2026 earnings commentary, limited production is slated to begin in late July or August 2026 on this converted line.
Tesla Optimus project fires up as Musk sees production line progress
Musk previously noted that Optimus features roughly 10,000 unique parts, making early output rates “literally impossible to predict” and describing them as “quite slow.” A larger dedicated factory at Giga Texas is under construction, targeting higher-volume production around summer 2027 with long-term annual capacity potentially reaching millions of units.
Some experts point out that pioneering humanoid robotics demands inventing new automation techniques, actuator supply chains, and quality-control standards in real time. Unlike vehicles, where components and assembly methods are mature, every element of Optimus—from dexterous hands to AI-integrated movement—requires fresh engineering solutions. Early units are expected to handle simple factory tasks before expanding to more complex roles.
This cautious approach aligns with Tesla’s history of under-promising and over-delivering on complex technologies. While enthusiasts hoped for rapid deployment, Musk’s message underscores a deliberate strategy: prioritize reliability and iterative improvement over rushed volume.
Analysts suggest the S-curve ramp typical of new manufacturing will eventually accelerate once foundational issues are resolved, positioning Optimus as a potential trillion-dollar product line.
Musk has long envisioned Optimus transforming labor markets, assisting in homes, factories, and hazardous environments. By setting realistic timelines, Tesla aims to build sustainable momentum rather than risk disappointment. As the Fremont line comes online this summer, investors and fans will watch closely for the first production metrics and capability demonstrations.
Tesla Semi involved in first known fatal crash in Nevada
Tesla expands Robotaxi to Florida, marking its third state for autonomy
