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NASA’s Webb Telescope mirror crushes “most optimistic predictions” after final alignment
NASA says that the nascent James Webb Space Telescope’s (JWST) “optical performance…continues to be better than the…most optimistic predictions” after completing the alignment of its record-breaking mirror.
Between 7 and 14 years behind schedule and over budget by a factor of 2 to 10, an Arianespace Ariane 5 rocket sent the Webb Telescope on its way to deep space on December 25th, 2021. Weighing 6.2 tons (~13,600 lb), JWST was almost half as heavy at liftoff as NASA’s iconic Hubble Space Telescope despite packing an unprecedented origami-like mirror with more than six times Hubble’s total collecting area. The combination of extreme mass reduction and extraordinary complexity required to launch such a large mirror so far from Earth with a rocket like Ariane 5 helps to partially explain why the Webb Telescope took so long (~18 years) and cost so much (~$9.7 billion) to design, develop, and build.
Nonetheless, launch it finally did. Ariane 5 did most of the work, sending the telescope on a trajectory that – with some help from its onboard thrusters – would guide it to the Sun-Earth L2 Lagrange point located some 1.5 million kilometers (~950,000 miles) from Earth. In perhaps the largest relief in the history of space-based observatories, the Webb Telescope’s immensely complex deployment process was then completed without a single major issue. 30 days after liftoff, the telescope – fully deployed – reached its operational orbit.
For the past four months, in comparison, almost all JWST work has focused on the less visible and far smaller processes of alignment and calibration. Each of JWST’s 18 main mirror segments has slowly but surely inched micrometer by micrometer into position while large swaths of the telescope slowly cooled to ambient temperatures – essential for maximum performance. Simultaneously, all of Webb’s primary instruments have achieved first light and entered the early phases of calibration and commissioning. Only after the instruments are painstakingly calibrated, the mirror is perfectly aligned, and crucial hardware is chilled to temperatures as low as -449°F (-267°C) can Webb begin to observe the universe and revolutionize large subsets of space science.
The first and most important step – mirror alignment – is now complete. The alignment process began in February 2022, six weeks after liftoff. First, images were captured with the unaligned mirror to help determine exactly what condition it was in. One by one, each of Webb’s 18 mirror segments were individually moved to determine which image each mirror was responsible for, which then allowed ground controllers to properly focus each mirror’s view of a target star. In a process known as “coarse phasing,” once those 18 points of light well-resolved and linked to a specific mirror segment, the segments were gradually steered on top of each other to produce a single image.
“Coarse” heavily undersells the almost unfathomable precision required to complete the step. To reach its full potential, each of the Webb Telescope’s mirror segments must be aligned to within 50 nanometers of each other. According to NASA, “if the Webb primary mirror were the size of the United States, each segment would be the size of Texas, and the team would need to line the height of those Texas-sized segments up with each other to an accuracy of about 1.5 inches.”
Fine phasing followed, involving an even more esoteric set of processes designed to focus the mirror as perfectly as possible. The resulting image was then tweaked to properly align it over the field of view of each of the Webb Telescope’s four main scientific instruments. Finally, some steps of the seven-step alignment process were redone or refined to fully optimize the mirror to the liking of its Earthbound creators and prospective users.
Ultimately, Webb Telescope alignment was extraordinarily successful, producing an image sharper and cleaner than even the “most optimistic predictions” made by its engineers. NASA says that the image is so detailed that it has effectively reached the physical resolution limit for a mirror the size of the Webb Telescope’s, meaning that it would have to violate the known laws of physics to resolve any more detail.
With mirror alignment complete, JWST has just one main hurdle left before science operations can begin: instrument commissioning. Commissioning is a catch-all phrase that covers a wide range of calibration, analysis, experiments, and optimization required to verify that JWST’s four main instruments are behaving as expected and accomplishing the work they were designed to do as accurately and reliably as possible.
At some point, the use of extraordinarily complex scientific instruments becomes more akin to an art form, and some degree of trust must be built up between scientists and their hopeful tools of the trade before they can confidently set chisel to marble and begin delving into the universe at unprecedented breadth and detail. If commissioning proceeds as smoothly as deployment and alignment, the JWST team could be ready to capture and share the telescope’s first actionable observations of the cosmos as early as July 2022.
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
