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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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Elon Musk
SpaceX turned a heralding moment for Starship into its greatest moment
Starship reached orbit despite losing an engine, deployed 26 Starlink V3 satellites on Flight 14.
SpaceX’s Starship reached orbit for the first time on Monday, and for a few nail-biting minutes it looked like it wouldn’t. During ascent on Flight 14, one of Ship 41’s six Raptor engines shut down early, and SpaceX’s livestream host Dan Huot told viewers the team had decided not to commit to orbit. Minutes later, after what Huot described as a lot of conversation in the control room, the final poll came back in favor, and a roughly 19 second burn of a single Raptor pushed the ship into orbit about 170 miles up.
The reversal matters because SpaceX had written the exit ramp into the mission plan. The company said it would only fire the orbital insertion burn if flight controllers confirmed enough backup hardware remained for the deorbit burn, a condition Teslarati laid out ahead of the flight. Losing an engine was exactly the scenario that rule was built for.
Pressing forward fits Elon Musk’s history. Falcon 1 failed three straight times before its fourth launch reached orbit in 2008, with SpaceX nearly out of money, and Starship was developed by flying prototypes until they broke. What changed this year SpaceX going public, and with $SPCX sliding below its IPO price in July when Flight 13 slipped, the short interest climbed significantly, as Teslarati reported at the time. A Starship potentially lost today with revenue generating next-gen Starlink satellites aboard would have landed directly on shareholders.
Splashdown confirmed. Congratulations to the entire SpaceX team on the first orbital flight of Starship! pic.twitter.com/urjmiwnvNl
— SpaceX (@SpaceX) September 28, 2026
That pressure showed up after orbit. SpaceX cut a flight planned to last nearly 10 hours to about three, moving splashdown from west of Chile to the North Pacific near Hawaii. SpaceX gave no reason, though Musk said this month the company was being extremely cautious about debris risk. The single Raptor for deorbit worked, and Ship 41 completed its flip and landing burn before breaking apart in the water, an outcome SpaceX expected. Musk has structured SpaceX’s governance to shield long term bets from market pressure.
The payload is the bigger business story. Musk posted that all 26 Starlink V3 satellites deployed and are “operating nominally.” Each V3 is rated for about 1 Tbps of downlink and 160 Gbps of uplink, so this single launch adds roughly 26 Tbps, about 10 times what a Falcon 9 load of V2 Mini satellites adds. The V3 is too large for Falcon 9, making Starship the only vehicle that can build out the planned 100,000 satellite constellation, at up to 60 per flight once it reaches routine service. Unlike the 20 V3 units on Flight 13, which reentered on a suborbital path, these will raise their orbits and could begin serving customers within weeks and bring in hundreds of millions of additional dollars in projected Starlink revenue.
SpaceX has already begun winding down Falcon 9 Starlink launches from Florida in favor of Starship. Reported targets put Flight 15 as early as October 19, leaving about three weeks to diagnose Monday’s engine shutdown before the next orbital attempt.
Starship’s 14th flight is set to launch on Monday, Sept 28. The 75-minute launch window opens at 7:15 a.m. CT. Live coverage of the mission starts ~35 minutes before launch → https://t.co/uQKQvgaTmJ
— SpaceX (@SpaceX) September 27, 2026
Tesla quietly doubled the size of its Cybercab fleet within the Robotaxi program in Austin, Texas, over the weekend to well over 100 units.
The move not only establishes more of the steering-wheel-less and pedal-less vehicles within the ride-sharing fleet Tesla has been operating for a year, but it also solidifies a more robust Robotaxi fleet as a whole.
Riders started receiving notifications from the Robotaxi app that stated: “Cybercab fleet has doubled: more rides available.”
I got this notification on the robotaxi app. They are saying the Cybercab fleet has doubled. Glad that they are advertising this pic.twitter.com/FFrnw4FRCF
— Abhimanyu Yadav (@WorldlyReviewer) September 26, 2026
Tesla first launched rides in the Cybercab in early September, although the Robotaxi fleet has been active for over a year, as rides began last Summer. Cybercab is truly Tesla’s most crucial vehicle release yet, as it is the first car any company has built that is geared toward full-fledged and end-to-end autonomy, never needing human intervention for anything.
Only available in Austin at the current time, Cybercab has two seats and has been spotted testing around various U.S. states and regions; Tesla plans to deploy the Cybercab in various U.S. cities in the coming months as a best-case scenario.
Tesla Cybercab gets initial tie-in to localized, in-house cathode plant
The availability of the Cybercab has doubled from just 58 units last Monday to 125 the following Friday. Marking a substantial increase in Cybercab availability, the additional ride-sharing units are more than welcome, as wait times for Cybercabs, especially, were quite high.
The dramatic increase is a sign that demand for Robotaxi is growing and Tesla is feeling more confident that its driverless ride-hailing suite, especially its Full Self-Driving software, is able to handle any traffic situation without explicit direction or supervision from a human being.
Tesla is advancing a fully automated pipeline for the 4680 battery cells used in its all-electric Semi, spanning production from Giga Texas through shipment and direct consumption on the line at the new dedicated Semi Factory in Sparks, Nevada.
The approach was outlined by Tesla at its September 24 Semi Handover event, which launched high-volume production at its new 1.8-million-square-foot plant in Nevada, which sits adjacent to Gigafactory Nevada and is designed for an annual production rate of 50,000 trucks per year.
After years of pilot builds and what was a four-year-long redesign of the truck, Tesla moved the Semi from 2170 batteries to its in-house 4680 cells, which are made in Austin. The change cuts battery mass and total energy while holding range, a key step in making volume production a realistic possibility.
Cells will leave Giga Texas in trailers, and at the Nevada Semi plant, Tesla intends for a dedicated line to unload those trailers automatically, station the cells, and feed them straight into pack and vehicle assembly.
🚨 Tesla plans to use a completely automated unloading process for cells coming from Giga Texas arriving at the Semi factory in Nevada
A line will “consume” cells from the trailer
The goal is to have zero human touch point throughout the entire process. Insane! pic.twitter.com/wdBFM8LC3F
— TESLARATI (@Teslarati) September 25, 2026
Both Lars Moravy, Tesla’s VP of Vehicle Engineering, and Dan Priestley, the Head of Tesla’s Semi program, described the goal as a “zero human touch point” from the moment the trailer arrives in Texas until a finished Semi drives off the production line in Nevada.
The unloading system that Moravy and Priestley described is just one piece of a much broader automation push. The plant uses what Tesla calls the highest-capacity electric monorail conveyance in vehicle manufacturing, carrying frames-in-white simultaneously. Powder-coating replaces conventional paint, and many processes that would normally require operators have been designed out.
Tesla has repeatedly said that “the best part is no part,” and the cell-handling plan extends that philosophy from the cell factory floor in Texas all the way to final assembly in Nevada.
If executed as described, the closed-loop flow would reduce labor, handling damage, and inventory buffers while tightening quality control on a component that represents a large share of the truck’s cost and weight. It also shortens the physical and organizational distance between two factories separated by more than 1,200 miles. The Semi itself now shares a bar-wound stator and other components with the Cybertruck, further linking Tesla’s passenger and commercial production systems.
High-volume output is expected to ramp gradually after the first trucks left the new line in April 2026. Early customers include PepsiCo, DHL, and U.S. Foods. Whether the automated trailer-to-line process reaches the promised zero-touch standard will be visible in the coming months as production scales. For Tesla, the Semi factory is another test of how far it can push “the machine that builds the machine” across sites.
SpaceX turned a heralding moment for Starship into its greatest moment
Tesla Cybercab fleet doubles to well over 100 units
