James Webb Space Telescope (JWST)

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Webb telescope fully deploys sunshield in mission milestone

The tennis court size, kite-shaped apparatus acts like a parasol, ensuring the observatory is kept in the shade so that it is able to detect faint infrared signals from the far reaches of the Universe.

The James Webb Space Telescope fully deployed its tennis-court sized sunshield Tuesday, a critical milestone for the success of its mission to study every phase of cosmic history, NASA said.

"All five layers of the sunshield are fully tensioned," said an announcer at the observatory's control center in Baltimore, where team members cheered, a live feed showed.

The 70-foot (21 meter) long, kite-shaped apparatus acts like a parasol, ensuring Webb's instruments are kept in the shade so they can detect faint infrared signals from the far reaches of the Universe.

Each of the layers was unfolded one by one over two days. Working together they offer an SPF (sun protection factor) of about one million.

Because the telescope was too large to fit into a rocket's nose cone in its operational configuration, it had to be transported folded, origami style. Unfurling is a complex and challenging task, the most daunting such deployment NASA has ever attempted.

https://phys.org/news/2022-01-webb-tele ... hield.html

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Webb deployment complete
08/01/2022 364 views 6 likes
ESA / Science & Exploration / Space Science / Webb

Today the James Webb Space Telescope team successfully fully deployed its iconic 6.4-metre, gold-coated primary mirror, completing the final stage of all major spacecraft deployments to prepare for science operations.

“The successful unfolding of the Webb telescope has been a complex but impressive engineering masterpiece. On behalf of ESA, I want to sincerely congratulate our colleagues at NASA for this achievement. Webb is an international partnership led by NASA, where ESA is providing key contributions in the form of instruments, science teams and, very importantly, a successful launch on Christmas Day from the European Spaceport in Kourou. I am grateful to NASA, CSA and our European team including CNES, Arianespace and ArianeGroup for this excellent cooperation,” says Josef Aschbacher, ESA Director General.

The two wings of Webb’s primary mirror were folded to fit inside the fairing of an ESA-provided Ariane 5 rocket prior to launch. After more than a week of other critical spacecraft deployments, the Webb team began remotely unfolding the hexagonal mirror segments of the largest mirror ever launched into space.

https://www.esa.int/Science_Exploration ... t_complete

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Space telescope's 'golden eye' opens, last major hurdle
https://phys.org/news/2022-01-space-tel ... major.html
by Marcia Dunn

NASA's new space telescope opened its huge, gold-plated, flower-shaped mirror Saturday, the final step in the observatory's dramatic unfurling.

The last portion of the 21-foot (6.5-meter) mirror swung into place at flight controllers' command, completing the unfolding of the James Webb Space Telescope.

"I'm emotional about it. What an amazing milestone. We see that beautiful pattern out there in the sky now," said Thomas Zurbuchen, chief of NASA's science missions.

More powerful than the Hubble Space Telescope, the $10 billion Webb will scan the cosmos for light streaming from the first stars and galaxies formed 13.7 billion years ago. To accomplish this, NASA had to outfit Webb with the largest and most sensitive mirror ever launched—its "golden eye," as scientists call it.

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[Kevin_Hall]

I think that those who are interested in already know it, nevertheless JWST is now fully deployed. Currently the golden segments of the telescope are being aligned. Here is a link for the live stream of the process.

[Yuli Ban]

If I recall correctly, first images should start coming back in June!

[raklian]

JWST just arrived home!

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Webb telescope spots its first star—and takes a selfie
https://phys.org/news/2022-02-webb-tele ... elfie.html

The first picture sent back of the cosmos is far from stunning: 18 blurry white dots on a black background, all showing the same object: HD 84406 a bright, isolated star in the constellation Ursa Major.

Star light, star bright, the James Webb Space Telescope has seen its first star (though it wasn't quite tonight)—and even taken a selfie, NASA announced Friday.

The steps are part of the months-long process of aligning the observatory's enormous golden mirror that astronomers hope will begin unraveling the mysteries of the early Universe by this summer.

The first picture sent back of the cosmos is far from stunning: 18 blurry white dots on a black background, all showing the same object: HD 84406 a bright, isolated star in the constellation Ursa Major.

But in fact it represents a major milestone. The 18 dots were captured by the primary mirror's 18 individual segments—and the image is now the basis for aligning and focusing those hexagonal pieces.

The light bounced off the segments to Webb's secondary mirror, a round object located at the end of long booms, and then to the Near Infrared Camera (NIRCam) instrument—Webb's main imaging device.

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Webb team brings 18 dots of starlight into hexagonal formation
https://phys.org/news/2022-02-webb-team ... gonal.html
by Alise Fisher, NASA

The James Webb Space Telescope team continues to make progress in aligning the observatory's mirrors. Engineers have completed the first stage in this process, called "Segment Image Identification." The resulting image shows that the team has moved each of Webb's 18 primary mirror segments to bring 18 unfocused copies of a single star into a planned hexagonal formation.

With the image array complete, the team has now begun the second phase of alignment: "Segment Alignment." During this stage, the team will correct large positioning errors of the mirror segments and update the alignment of the secondary mirror, making each individual dot of starlight more focused. When this "global alignment" is complete, the team will begin the third phase, called "Image Stacking," which will bring the 18 spots of light on top of each other.

"We steer the segment dots into this array so that they have the same relative locations as the physical mirrors," said Matthew Lallo, systems scientist and Telescopes Branch manager at the Space Telescope Science Institute. "During global alignment and Image Stacking, this familiar arrangement gives the wavefront team an intuitive and natural way of visualizing changes in the segment spots in the context of the entire primary mirror. We can now actually watch the primary mirror slowly form into its precise, intended shape!"

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Webb turns those 18 separate star images into a single unified star. Next comes even better focus.

It’s coming together! Engineers for the James Webb Space Telescope have now completed two more phases of the seven-step, three-month-long mirror alignment process. This week, the team made more adjustments to the mirror segments along with updating the alignment of its secondary mirror. These refinements allowed for all 18 mirror segments to work together — for the first time — to produce one unified image.

As you can see in the image above, this view of the star HD 84406 shows one image instead of the 18 views – one from each segment – that we saw earlier this week. NASA engineers say that after future alignment steps, the image will be even sharper.

https://www.universetoday.com/154683/we ... ore-154683

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James Webb Space Telescope Aligning Its Mirrors
March 14, 2022 by Brian Wang
https://www.nextbigfuture.com/2022/03/j ... rrors.html

In recent weeks, the James Webb Space Telescope team successfully captured starlight through each of Webb’s 18 mirror segments. They refined and stacked those 18 individual dots of light on top of one another to form an initial alignment image of a single star. Since then, in stages of alignment called “coarse phasing” and “fine phasing,” engineers have made smaller adjustments to the positions of Webb’s 18 primary mirror segments so they act as a single mirror, producing a sharp and focused image of a single star.

NASA will hold a virtual media briefing at noon EDT Wednesday, March 16, to provide an update on the James Webb Space Telescope’s mirror alignment. The briefing will air live on NASA TV, the NASA app, and the agency’s website.

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James Webb: 'Fully focused' telescope beats expectations
Source: BBC

Engineers say they have now managed to fully focus the $10bn observatory on a test star. The pin-sharp performance is even better than hoped, they add.

To get to this stage, all of Webb's mirrors had to be aligned to tiny fractions of the width of a human hair.

But the agency cautions that a lot of work still lies ahead before the telescope can be declared operational.

Lee Feinberg, the Nasa engineer who has led the development of Webb's optical elements, described the release of the first properly focused image as phenomenal.

Read more: https://www.bbc.com/news/science-environment-60771210

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James Webb telescope's coldest instrument reaches operating temperature
https://phys.org/news/2022-04-james-web ... ument.html
by NASA's Goddard Space Flight Center

NASA's James Webb Space Telescope will see the first galaxies to form after the Big Bang, but to do that, its instruments first need to get cold—really cold. On April 7, Webb's Mid-Infrared Instrument (MIRI)—a joint development by NASA and ESA (European Space Agency)—reached its final operating temperature below 7 kelvins (minus 447 degrees Fahrenheit, or minus 266 degrees Celsius).

Along with Webb's three other instruments, MIRI initially cooled off in the shade of Webb's tennis-court-size sunshield, dropping to about 90 kelvins (minus 298 F, or minus 183 C). But dropping to less than 7 kelvins required an electrically powered cryocooler. Last week, the team passed a particularly challenging milestone called the "pinch point," when the instrument goes from 15 kelvins (minus 433 F, or minus 258 C) to 6.4 kelvins (minus 448 F, or minus 267 C).

"The MIRI cooler team has poured a lot of hard work into developing the procedure for the pinch point," said Analyn Schneider, project manager for MIRI at NASA's Jet Propulsion Laboratory in Southern California. "The team was both excited and nervous going into the critical activity. In the end it was a textbook execution of the procedure, and the cooler performance is even better than expected."