News
SpaceX CEO Elon Musk posts uncut Raptor, drone videos of Starhopper’s flight test debut
Some two hours after Starhopper’s inaugural untethered flight, SpaceX CEO Elon Musk took to Twitter to post an uncut video showing the ungainly rocket’s launch and landing from the perspective of both a drone and Starhopper’s lone Raptor engine.
As noted by commenters, Starhopper’s first flight also marks perhaps an even more fascinating milestone: it’s technically the first launch ever of a full-flow staged-combustion (FFSC) rocket engine. Whether or not the development hell Raptor required is or was worth it to SpaceX, the company has become the first and only entity on Earth to develop and fly a FFSC engine, beating out the national space agencies of both the United States and Soviet Union, both of which built – but never flew – prototypes.
Instead of inexplicably shelving a mature prototype development and test program, SpaceX iterated through several subscale Raptor prototypes, test-fired the engines for more than 1200 seconds total, used that data to design and build full-scale Raptors, and finally sped into a hardware-rich test campaign with six (soon to be seven) new engines. After SpaceX settled on a full-flow staged-combustion cycle and methane/oxygen (methalox) propellant, Raptor conducted its first full-scale tests all the way back in 2014, performing preburner flow and ignition tests at NASA’s Stennis Space Center.
Two years and many additional subcomponent tests later, SpaceX successfully performed the inaugural static fire test of its first completed subscale Raptor, a huge milestone for any rocket engine. In the 12 months following its first static fire (September 2016), SpaceX performed dozens of static fire tests with several subscale engines, putting the new propulsion system through >1200 seconds of combined testing.
A year after that, SpaceX was still testing subscale engines but the first full-scale Raptor engine was just a few months away from completing assembly in Hawthorne and heading to McGregor to kick off full-scale static fire testing. Indeed, four months after CEO Elon Musk’s September 2018 update, Raptor serial number 01 (SN01) shipped to Texas in late January and successfully ignited for the first time on February 3rd. SpaceX’s finalized full-scale Raptor engine is designed to produce more than 2000 kN (450,000 lbf, 200 tons) of thrust at full-throttle.
Since that inaugural ignition, SpaceX’s propulsion team – perhaps to their detriment, under orders from Musk – pushed SN01 and several of its successors to their limits as quickly as possible, resulting in severe, irreparable damage in several cases. On the other hand, the no-holds-barred, ‘hardware-rich’ (i.e. destructive) test program has allowed SpaceX to relatively quickly solve several major bugs that prevented the engine from passing longer test fires.
Raptor SN05 was originally expected to support Starhopper’s first flight(s) but had to be passed up after suffering damage in one of its final June 2019 acceptance tests. Raptor SN06 became the first engine – likely thanks to tweaks afforded by data gathered from its failed brethren – to pass all of those acceptance tests, leading to its eventual installation on Starhopper in early July.
Raptor’s impressive development culminated on July 25th with the engine’s first untethered flight while attached to Starhopper, a 9m-diameter (30 ft) low-fidelity prototype that is more or less a mobile test stand for the next-generation SpaceX engine. Raptor is now the only FFSC engine in history that has powered a flight-capable vehicle’s launch and landing, even if said flight featured an apogee of just 20-30 meters (65-100 ft).
“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.“
SpaceX delays Starhopper’s first flight a few days despite Raptor preburner test success
For more on what exactly makes full-flow staged-combustion engines uniquely capable and challenging to develop, the subject has been covered at length in past Teslarati articles.
According to Musk, the next major challenge facing Starhopper and (presumably) Raptor SN06 is far more ambitious 200-meter (650 ft) hop and flight test that could happen as soon as the first half of August.
Check out Teslarati’s Marketplace! We offer Tesla accessories, including for the Tesla Cybertruck and Tesla Model 3.
Tesla has reached a notable benchmark in its autonomous driving program after its Robotaxi fleet surpassed one million miles of unsupervised operation. The company made the announcement during its Cybercab event in Austin on September 3.
Tesla Vice President of AI Ashok Elluswamy told attendees he was happy to report the fleet had achieved one million miles of unsupervised Robotaxi operation as a testament to safety.
The new total marked a sharp increase from the 380,000 unsupervised miles Tesla disclosed during its second-quarter 2026 earnings update in late July.
In roughly six weeks, the company added about 620,000 miles. That acceleration followed Tesla’s decision to remove in-vehicle safety monitors from most of its operations outside the San Francisco Bay Area.
Credit: Tesla
Tesla first launched Robotaxi service in Austin in June 2025 with safety drivers present. It later began fully unsupervised rides and expanded into Dallas, Houston, Miami, Orlando, and Tampa. The San Francisco Bay Area remains the exception, where a safety monitor still rides in the vehicle under California permitting rules.
The company has not released a city-by-city breakdown of the one million unsupervised miles.
The milestone arrived as Tesla began offering public Cybercab rides in Austin. The purpose-built vehicle has no steering wheel or pedals and is designed only for autonomous ride-hailing. Production versions joined the existing fleet of modified Tesla vehicles already operating in the service.
Tesla’s unsupervised mileage is growing at a double-digit weekly rate according to earlier company comments, yet its fleet size remains modest compared with established competitors. Waymo has accumulated more than 200 million fully autonomous rider-only miles. Tesla has described its own unsupervised operations as having recorded zero notable incidents in the period leading up to the July update.
The one-million-mile figure reflects Tesla’s shift from supervised testing to broader driverless service in multiple states. It also highlights the company’s strategy of using both existing Model Y vehicles and the new Cybercab to scale its network.
Credit: Tesla
Whether the rapid recent growth continues will depend on further city expansions, regulatory approvals, and the performance of the purpose-built Cybercab in everyday paid rides. Tesla has not specified how many of the latest miles involved the new vehicle versus the rest of the fleet.
The announcement underscores Tesla’s progress toward a larger robotaxi network while illustrating the remaining gap in total autonomous experience relative to longer-operating rivals.
Tesla AI lead Ashok Elluswamy said this week that 24-hour Robotaxi service is close. Replying on X to a rider who wanted Cybercab trips all night, he wrote that the capability would arrive “next month or so” once “the next tech to merge on the v15 plan” is ready.
The comment landed on September 4, one day after Tesla opened public Cybercab rides in Austin. It is the clearest near-term timeline yet for overnight unsupervised operation. Tesla’s paid Robotaxi network currently runs from 6 a.m. to 10 p.m. seven days a week across Austin, Dallas, Houston, Miami, Orlando, and Tampa.
next month or so. the next tech to merge on the v15 plan will enable it.
— Ashok Elluswamy (@aelluswamy) September 4, 2026
That 16-hour window is shorter than the 6 a.m. to 2 a.m. schedule the company used for much of the prior year.
Elluswamy did not name the specific feature or say whether the change would apply first to purpose-built Cybercabs, the existing Model Y fleet, or both. He also offered no city-by-city rollout list. The link to Full Self-Driving v15 is nevertheless significant.
Tesla has described v15 as a step-change architecture with seven parallel improvement tracks and roughly ten times more parameters than earlier builds. Early versions of that software already operate on the Robotaxi fleet and contain about 40 percent of the planned gains.
By July 2026, the unsupervised fleet had logged more than 380,000 miles across six cities in two states with what the company called an impeccable safety record and no notable incidents caused by the vehicles themselves. Tesla has repeatedly argued that camera-based end-to-end neural networks, rather than extra sensors, are the core of the solution.
Overnight service would test that claim in lower-light conditions and would also raise vehicle utilization, a key variable for Robotaxi unit economics. The company has already begun using public Superchargers at night and is building dedicated Robotaxi charging sites.
Riders have asked why software must change if the cars already drive in the dark. The practical answer appears to be reliability and scale: Tesla has held back mass expansion until more of the v15 stack is merged, citing the need for higher confidence before putting thousands of unoccupied vehicles on streets around the clock.
If the next module arrives on the timetable Elluswamy sketched, 24-hour service could begin in October 2026 in at least some markets.
That would mark a shift from a daytime-bounded pilot to a service that can run whenever demand exists, including the late-night hours that have so far remained out of reach.
Tesla is beginning to roll out Full Self-Driving Supervised v14.3.9 with a new active safety layer that can take control even when the driver is operating the car manually.
Tesla AI said the software can activate FSD on the driver’s behalf when an imminent collision is detected and Automatic Emergency Braking may not be enough. It may also engage if the system detects heavy distraction or an accidental FSD disengagement.
FSD Supervised v14.3.9 starting to roll out shortly
This release includes a new active safety feature set: FSD Supervised can now activate on your behalf when an imminent collision is detected and Automatic Emergency Braking (AEB) may not be enough.
It may also engage if we…
— Tesla AI (@Tesla_AI) September 4, 2026
The capability is essentially Automatic Collision Evasion. However, unlike conventional AEB, which mainly applies the brakes in a straight line, this feature can use steering, braking, and acceleration together if the car calculates that stopping alone will not prevent impact and a safer path exists. The system may change lanes or move toward a shoulder when conditions allow, then continue driving after the immediate threat is handled rather than simply coming to a stop.
The intervention is meant as a last-resort safety net, not a replacement for attentive driving.
Tesla Full Self-Driving v14.3.7 early review: FSD saved me from an accident
Tesla’s own description still frames FSD as supervised assistance. Secondary reports on internal release notes say the feature can fire while the car is being driven manually if cabin-camera monitoring suggests the driver is not sufficiently attentive, such as reaching toward the back seat, or if FSD appears to have been turned off unintentionally.
After the emergency maneuver, the car is expected to alert the driver and request a return to manual control.
The safety case is straightforward. Many collisions happen in the last second because a driver is looking away, fumbles a control, or faces an obstacle that braking cannot fully solve. A system that can both recognize that AEB is insufficient and execute a coordinated evasive path can reduce those remaining high-severity events.
Re-engaging after accidental disengagement also addresses a practical failure mode: a small steering nudge that drops FSD at the worst moment. The advantage is a background safety net that uses the same vision stack already running in v14, instead of leaving the car solely to emergency braking once the driver is no longer in command.
The feature still depends on FSD being enabled and, according to reports, an active FSD purchase or subscription. It does not make the vehicle unsupervised. Drivers remain responsible, and Tesla has not published how often the system is expected to intervene or how it will handle false positives.
If the rollout is conservative and the false-alarm rate stays low, the update is a meaningful step: FSD is no longer only a feature the driver turns on. In the rare moments when disaster is already forming, it can step in.
Tesla crosses major Unsupervised Self-Driving milestone
Tesla Robotaxi will be a 24/7 service: here’s when
