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NASA’s Webb Telescope mirror crushes “most optimistic predictions” after final alignment

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3 years ago

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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.

An inward view of the fruits of alignment. (NASA)

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.”

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The product of coarse phasing – beautiful but not yet scientifically useful. (NASA)

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.

https://twitter.com/AndrasGaspar/status/1520184730985148418
JWST’s first images with a fully aligned mirror. (NASA)

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.

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Eric Ralph is Teslarati's senior spaceflight reporter and has been covering the industry in some capacity for almost half a decade, largely spurred in 2016 by a trip to Mexico to watch Elon Musk reveal SpaceX's plans for Mars in person. Aside from spreading interest and excitement about spaceflight far and wide, his primary goal is to cover humanity's ongoing efforts to expand beyond Earth to the Moon, Mars, and elsewhere.

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Elon Musk reveals SpaceX’s target for Starship’s 10th launch

Elon Musk has revealed SpaceX’s target timeline for the next Starship launch, which will be the tenth in program history.

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18 minutes ago

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July 16, 2025

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Credit: SpaceX

Elon Musk has revealed SpaceX’s target timeline for the next Starship launch, which will be the tenth in program history.

Musk says SpaceX is aiming for a timeline of roughly three weeks from now, which would come about ten weeks after the previous launch.

Coincidentally, it would bring the two launches 69 days apart, and if you know anything about Elon Musk, that would be an ideal timeline between two launches.

SpaceX is coming off a test flight in which it lost both the Super Heavy Booster and the Upper Stage in the previous launch. The Super Heavy Booster was lost six minutes and sixteen seconds into the flight, while SpaceX lost communication with the Ship at 46 minutes and 48 seconds.

Musk is aiming for the tenth test flight to take place in early August, he revealed on X:

This will be SpaceX’s fourth test flight of the Starship program in 2025, with each of the previous three flights bringing varying results.

IFT-7 in January brought SpaceX its second successful catch of the Super Heavy Booster in the chopstick arms of the launch tower. The ship was lost after exploding during its ascent over the Turks and Caicos Islands.

IFT-8 was on March 6, and SpaceX caught the booster once again, but the Upper Stage was once again lost.

The most recent flight, IFT-9, took place on May 27 and featured the first reused Super Heavy Booster. However, both the Booster and Upper Stage were lost.

The Federal Aviation Administration (FAA) hit SpaceX with a mishap investigation for Flight 9 on May 30.

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Elon Musk confirms Tesla is already rolling out a new feature for in-car Grok

Tesla is already making in-car Grok more robust with a simple but effective feature that CEO Elon Musk says is “coming.”

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7 hours ago

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July 16, 2025

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Credit: Tesla

Tesla CEO Elon Musk has confirmed that the company will roll out a new feature for in-car Grok as it is rolling out to vehicles for the first time.

Grok was just recently added as a feature to Tesla vehicles within the past week, but owners are already requesting some small changes to make it more convenient to use.

Tesla debuts hands-free Grok AI with update 2025.26: What you need to know

The first is already on the way, Musk confirmed, as WholeMarsBlog requested a simple, but useful feature for Grok as it is used within Tesla vehicles.

Whole Mars requested that “Hey Grok” be used as a wake word, automatically activating the AI assistant without having to touch any buttons. Musk confirmed it is already in development and on the way to vehicles:

This feature is incredibly similar to that of “Hey Siri” with iPhones and other iOS devices. The phone will recognize your voice and hear that prompt, automatically activating Siri. Apple’s assistant will then perform whatever task it is asked to perform. It’s a simple but effective performance feature.

Grok is already getting its first reviews from owners as it rolls out to owners for the first time. It is a long time coming, too. Tesla has been hinting that Grok would be enabled in the vehicles for a while now, and it just started its initial rollout last week.

Grok is available in vehicles with the AMD chip and requires Premium Connectivity or a WiFi connection to use.

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Tesla reveals key detail of Supercharger Diner, but it’s bigger than you think

Tesla has finally released one key detail about the Supercharger Diner, and it is bigger than what it appears at face-value.

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9 hours ago

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July 16, 2025

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Credit: Tesla

Tesla has revealed a key detail of its Supercharger Diner as its launch date appears to be nearing, based on what we are seeing at the site currently.

The Supercharger Diner is located on Santa Monica Boulevard in Los Angeles and was first proposed as an idea by CEO Elon Musk back in 2018. Musk envisioned a drive-in movie-style 1950s-inspired diner that would feature elements such as servers on roller skates, large movie screens, and a menu inspired by classic treats from several decades ago.

A project that first broke ground in 2023, the Supercharger Diner has been in development for over two years, as Tesla performed demolition work at the site back in February of that year.

It has slowly moved forward, and drone footage shot this week seems to show things are nearly up and running. Musk even mentioned that he had eaten at the Diner Supercharger this week.

There are still details that Tesla has yet to announce and confirm. The most important thing is regarding the menu that will be served at the diner.

Tesla has not hinted at what it will be making for patrons at the restaurant, but Musk commended the food and said the diner would be one of the coolest spots in LA.

However, we now have details on another important thing about the restaurant: the hours.

Images taken by Aaron Cash of ABetterTheater.com show the diner will be open 24/7, as it appears on the front doors of the diner:

At first thought, it seems this will operate like any other diner, as many are open for 24 hours a day. Diners typically serve large menus with numerous options, catering to the tastes and moods of anyone who walks in.

People of all walks of life eat at diners, as the food is typically affordable, tasty, and available at any hour to serve those who are night owls or those who work non-typical schedules.

However, Tesla is a bit different, and it seems that this new venture into food service could eventually transition from human servers and cooks to robots, most notably the company’s in-house project of Optimus.

It is something straight out of a Star Wars movie. I can think of Obi-Wan Kenobi visiting Dex in his diner in Attack of the Clones to figure out where a poison dart was sourced from:

Eventually, Optimus will likely be working as an employee in the Tesla Diner, and 24/7 operation will be performed by the humanoid robot that aims to eliminate trivial tasks from humans.

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