{"id":24632,"date":"2022-04-29T00:15:42","date_gmt":"2022-04-28T16:15:42","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/james-webb-telescope-completes-optical-alignment-ready-for-final-instrument-calibration-phase-of-commissioning\/"},"modified":"2022-04-29T00:15:42","modified_gmt":"2022-04-28T16:15:42","slug":"james-webb-telescope-completes-optical-alignment-ready-for-final-instrument-calibration-phase-of-commissioning","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/james-webb-telescope-completes-optical-alignment-ready-for-final-instrument-calibration-phase-of-commissioning\/","title":{"rendered":"James Webb telescope completes optical alignment, ready for final instrument calibration phase of commissioning"},"content":{"rendered":"<p>The James Webb Space Telescope (JWST) has entered a new phase of its commissioning process as NASA announces that the observatory has completed its mirror alignment and focusing process and is ready to move into the instrument calibration ahead of full science operations later this year.<\/p>\n<p>\u201cThese remarkable test images from a successfully aligned telescope demonstrate what people across countries and continents can achieve when there is a bold scientific vision to explore the universe,\u201d said Lee Feinberg, Webb optical telescope element manager at NASA\u2019s Goddard Space Flight Center.<\/p>\n<p>To discuss this milestone, NASASpaceflight spoke with Charlie Atkinson, Chief Engineer for Northrop Grumman\u2019s JWST Program, regarding the status of the telescope, its performance so far, and what remains for the prime contractor as the telescope moves toward operational status.<\/p>\n<\/p>\n<p>Optical alignment of James Webb Space Telescope<\/p>\n<p>\u201cEvery step of the way, things have been going either exactly as planned or better than planned, which has just been an incredibly great feeling,\u201d said Atkinson, who\u2019s been with the Webb program for Northrop Grumman since 1998.<\/p>\n<p>One of those better-than-expected performance points comes from the optical performance of the telescope. As Atkinson explained, \u201cWe\u2019re getting an indication that the actual optical performance of the telescope is actually better than we expected.\u201d&nbsp;<\/p>\n<\/p>\n<p><iframe title=\"NASA\u2019s Webb Reaches Alignment Milestone, Optics Working Successfully\" src=\"https:\/\/www.youtube.com\/embed\/MiGx8xv6xjE?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen=\"\" name=\"fitvid0\" data-gtm-yt-inspected-14=\"true\" data-gtm-yt-inspected-21=\"true\"><\/iframe><\/p>\n<p>Spaceflight history books<path d=\"M7.59009 18.59L9.00009 20L17.0001 12L9.00009 4L7.59009 5.41L14.1701 12\" style=\"animation: initial !important; background: initial !important; border: 0px !important; box-shadow: none !important; color: inherit !important; cursor: inherit !important; direction: inherit !important; display: inline !important; fill: currentcolor !important; filter: initial !important; float: none !important; margin: 0px !important; opacity: initial !important; outline: 0px !important; overflow: initial !important; padding: 0px !important; stroke: initial !important; transform: initial !important; vertical-align: initial !important; visibility: inherit !important;\"><\/path>Space tourism guides<path d=\"M7.59009 18.59L9.00009 20L17.0001 12L9.00009 4L7.59009 5.41L14.1701 12\" style=\"animation: initial !important; background: initial !important; border: 0px !important; box-shadow: none !important; color: inherit !important; cursor: inherit !important; direction: inherit !important; display: inline !important; fill: currentcolor !important; filter: initial !important; float: none !important; margin: 0px !important; opacity: initial !important; outline: 0px !important; overflow: initial !important; padding: 0px !important; stroke: initial !important; transform: initial !important; vertical-align: initial !important; visibility: inherit !important;\"><\/path>Aerospace &amp; Defense<path d=\"M7.59009 18.59L9.00009 20L17.0001 12L9.00009 4L7.59009 5.41L14.1701 12\" style=\"animation: initial !important; background: initial !important; border: 0px !important; box-shadow: none !important; color: inherit !important; cursor: inherit !important; direction: inherit !important; display: inline !important; fill: currentcolor !important; filter: initial !important; float: none !important; margin: 0px !important; opacity: initial !important; outline: 0px !important; overflow: initial !important; padding: 0px !important; stroke: initial !important; transform: initial !important; vertical-align: initial !important; visibility: inherit !important;\"><\/path>\n<p>     (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n<p>Atkinson elaborated, commenting on the fact that all space telescopes carry an optical error budget to account for certain parts of the manufacturing process that can contribute to the degradation of the optics, such as imperfect polishing of the mirrors and imperfect alignment of those mirrors.<\/p>\n<p>Additionally, some optical degradation can come from the telescope\u2019s mandatory systems, which for Webb includes the observatory\u2019s reaction control wheels and cryocooler, both of which induce disturbances, or \u201cjitters,\u201d into the system.<\/p>\n<h4 class=\"widget-title penci-border-arrow\">See Also<\/h4>\n<ul>\n<li>JWST Mission Updates<\/li>\n<li>Space Science coverage<\/li>\n<li>L2 Future Spacecraft<\/li>\n<li>Click here to Join L2<\/li>\n<\/ul>\n<p>With all those factors in place, the team has been able to compare predictions to reality. \u201cWhen you put it all together, it\u2019s actually performing a lot better than those allocations we were given,\u201d noted Atkinson.<\/p>\n<p>But to get to the point where the optics could be tested, the 18 individual segments of the James Webb Space Telescope\u2019s primary mirror had to be aligned. A process that is more complicated than it might sound.<\/p>\n<p>(Click here to for NASASpaceflight\u2019s coverage archive on the James Webb Space Telescope)<\/p>\n<p>To begin with, James Webb\u2019s primary mirror had to be assembled from 18 smaller individual mirror segments. And those individual mirror segments could not be fully integrated and aligned on the ground because the 8.4-meter diameter mirror was too large to fit into any payload fairing for launch. So the mirror had to be folded up in sections and then unfolded in space.<\/p>\n<p>Once the unfolding process was complete, the next step was to move each of the 18 mirror segments out of their launch lock configurations by about half an inch \u2014 a process that took several days to complete because of how slow the motors are designed to move for fine alignment procedures.<\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" aria-describedby=\"caption-attachment-55237\" class=\"size-full wp-image-55237\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/03\/james-web-space-telescope.jpg\" alt=\"\" width=\"816\" height=\"508\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/03\/james-web-space-telescope.jpg 816w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/03\/james-web-space-telescope-350x218.jpg 350w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/03\/james-web-space-telescope-562x350.jpg 562w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/03\/james-web-space-telescope-768x478.jpg 768w\" sizes=\"(max-width: 816px) 100vw, 816px\"><\/p>\n<p id=\"caption-attachment-55237\" class=\"wp-caption-text\">NASA\u2019s James Webb Space Telescope. (NASA)<\/p>\n<p>Then the team had to figure out where each of those mirror segments was pointing so they could align them all together into what is an effective single mirror.&nbsp;<\/p>\n<p>\u201cAt this point, we [had] a telescope that [hadn\u2019t] really started to be aligned,\u201d said Atkinson. \u201cWe needed to go find out where those 18 individual images were. And we did what\u2019s called a mosaic pattern.\u201d<\/p>\n<p>This involved spinning the observatory in a spiral pattern to allow the desired imaging target to be seen by all 18 mirror segments.<\/p>\n<p>\u201cAnd the good news is that it didn\u2019t take long to do that because that collection of 18 images was not very far from ideal alignment,\u201d said Atkinson.<\/p>\n<p>Once those images were collected, the team then needed to figure out which mirror was looking at which image. To do this, they slowly moved one mirror at a time and watched to see which image moved.<\/p>\n<p>This was necessary to provide one piece of the information needed to move each mirror segment to align them all together.<\/p>\n<\/p>\n<p><iframe title=\"The James Webb Space Telescope's Folding Mirrors\" src=\"https:\/\/www.youtube.com\/embed\/xHTciBIEtmY?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" allowfullscreen=\"\" name=\"fitvid1\" data-gtm-yt-inspected-14=\"true\" data-gtm-yt-inspected-21=\"true\"><\/iframe><\/p>\n<p>Once those identifications were complete, the team then performed the initial focus sweep, changing the focus of the secondary mirror and changing its distance from the primary mirror to see how the images changed.<\/p>\n<p>\u201cThat allowed us to do two things. One it gave us the initial location of where we want to put the secondary mirror, to find kind of the optimum position,\u201d related Atkinson.<\/p>\n<p>The second item provided was the final piece of information on how to move each primary mirror segment for alignment.<\/p>\n<p>\u201cThe entire process to get it from when we first moved them out off of their launch locks to the point where we\u2019ve got the telescope completely aligned, that was about two months,\u201d said Atkinson.<\/p>\n<p>Overlapping operations<\/p>\n<p>While this work with the mirror progressed, other teams were busy bringing Webb\u2019s science instruments online and putting them through their initial checkouts.<\/p>\n<p>For Northrop Grumman, this period also included their cryocooler\u2019s main task of chilling the observatory down to just 6 Kelvin, the required maximum operating temperature of the MIRI (mid-infrared instrument).<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-85788\" class=\"size-full wp-image-85788\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b.jpg\" alt=\"\" width=\"1024\" height=\"678\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b.jpg 1024w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b-350x232.jpg 350w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b-529x350.jpg 529w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b-768x509.jpg 768w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b-780x516.jpg 780w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/27433983430_74355aa30c_b-263x175.jpg 263w\" sizes=\"(max-width: 1024px) 100vw, 1024px\"><\/p>\n<p id=\"caption-attachment-85788\" class=\"wp-caption-text\">The cryocooler for the MIRI. The MIRI requires a lower operating temperature than Webb\u2019s other instruments, and the cryocooler accommodates this requirement. (Credit: NASA\/JPL-Caltech)<\/p>\n<p>\u201cThe temperatures have basically stopped changing,\u201d noted Atkinson when speaking about the cryocooler\u2019s performance. \u201cThey\u2019re still changing a little bit, but for the most part we\u2019re pretty stable at this point.\u201d<\/p>\n<p>The cryocooler was a significant portion of the observatory that could not be fully tested end-to-end on the ground due to the telescope\u2019s operational size.<\/p>\n<p>\u201cThere were a number of situations like that where just because of ground environments with gravity, with temperature cases, with such a large observatory, you [couldn\u2019t] pack the whole thing into one chamber because there [wasn\u2019t] one that [was] big enough to go test it.\u201d<\/p>\n<p>\u201cSo we tested the cryocooler itself as an entity to make sure that it was going to be able to get the right amount of coolant, the right pressure, the right temperature conditions. And we tested the infrared instrument to make sure that it was going to react appropriately. But you\u2019ll never know until you go through the whole thing,\u201d said Atkinson.<\/p>\n<p>Part of the cryocooler\u2019s operation involved running its coolant lines up a deployable boom from the telescope\u2019s main control bus up to the MIRI instrument, a deployment that stretched the cryocooler\u2019s lines like a Slinky.<\/p>\n<p>\u201cThat had never been checked out,\u201d added Atkinson. \u201cBut all the testing we did on the ground give us high confidence that was going to work.\u201d<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-85789\" class=\"size-full wp-image-85789\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-scaled.jpeg\" alt=\"\" width=\"2560\" height=\"1619\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-scaled.jpeg 2560w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-350x221.jpeg 350w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-554x350.jpeg 554w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-768x486.jpeg 768w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-1920x1214.jpeg 1920w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/04\/FN-274yXMAEn9x_-1170x740.jpeg 1170w\" sizes=\"(max-width: 2560px) 100vw, 2560px\"><\/p>\n<p id=\"caption-attachment-85789\" class=\"wp-caption-text\">While the purpose of this image was to focus on the bright star at the center for alignment evaluation, Webb\u2019s optics and NIRCam are so sensitive that the galaxies and stars seen in the background show up. (Credit: NASA\/STScI)<\/p>\n<p>And it has.<\/p>\n<p>Future with JWST for Northrop Grumman<\/p>\n<p>As Webb moves through the final phases of its commissioning, Northrop Grumman\u2019s work with the observatory will not end when it enters science operations.<\/p>\n<p>The testbed that has been built on the ground will continue to be used to test software upgrades and to evaluate and analyze anything that might go wrong with Webb that requires a fix.<\/p>\n<p>\u201cIf there\u2019s an anomaly and we can go test that out on the testbed to say \u2018Yep, that kind of behavior results if this is what happened on the observatory\u2019, and then we can test out, \u201cOkay well, how do we want to fix that?\u2019, noted Atkinson.&nbsp;<\/p>\n<p>\u201cSo that kind of a maintenance operation is something that we\u2019ll definitely be doing for James Webb for its foreseeable life.\u201d<\/p>\n<p><em>(Lead image: Engineering images of sharply focused stars in the field of view of each instrument demonstrate that the telescope is fully aligned and in focus. Credit: NASA\/STScI)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The James Webb Space Telescope (JWST) has entered a new phase of its commissioning process as NASA announces that the observatory has completed its mirror alignment and focusing process and is ready to move into the instrument calibration ahead of full science operations later this year. \u201cThese remarkable test images from a successfully aligned telescope [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1560,1691,190,554],"class_list":["post-24632","post","type-post","status-publish","format-standard","hentry","category-news","tag-james-webb-space-telescope","tag-jwst","tag-nasa","tag-northrop-grumman"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24632"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=24632"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24632\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=24632"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=24632"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=24632"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}