{"id":10677,"date":"2022-02-12T00:59:25","date_gmt":"2022-02-11T16:59:25","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/engineers-pleased-with-webbs-progress-as-mirror-alignment-gets-underway\/"},"modified":"2022-02-12T00:59:25","modified_gmt":"2022-02-11T16:59:25","slug":"engineers-pleased-with-webbs-progress-as-mirror-alignment-gets-underway","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/engineers-pleased-with-webbs-progress-as-mirror-alignment-gets-underway\/","title":{"rendered":"Engineers pleased with Webb\u2019s progress as mirror alignment gets underway"},"content":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION<\/p>\n

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This \u201cselfie\u201d was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of space. This configuration is not used during scientific operations and is used strictly for engineering and alignment purposes. In this case, the bright segment was pointed at a bright star, while the others aren\u2019t currently in the same alignment. This image gave an early indication of the primary mirror alignment to the instrument. Credit: NASA<\/figcaption><\/figure>\n

The first images captured by the James Webb Space Telescope were unveiled Friday, a \u201cselfie\u201d showing the observatory\u2019s 21.3-foot-wide primary mirror and a mosaic showing multiple images of a nondescript star being used to align the 18 segments making up the main mirror.<\/p>\n

While the blurry, misaligned pictures might disappoint the uninitiated, they are almost exactly what engineers were expecting at this point in the observatory\u2019s complex commissioning, 48 days after its Christmas Day launch.<\/p>\n

\u201cThis amazing telescope has not only spread its wings, but it has now opened its eyes,\u201d said Lee Feinberg, Webb optical elements manager.<\/p>\n

NASA is now in the process of aligning the 18 hexagonal segments that make up Webb\u2019s huge main mirror, carefully adjusting the tilt of each one in tiny increments to align the multiple reflections of target stars into a single beam like the one produced by a one-piece mirror.<\/p>\n

So far, Feinberg said, the tedious work has gone remarkably smoothly, with no major problems or setbacks.<\/p>\n

\u201cThe only thing I want to caution is that it\u2019s still very early,\u201d he said. \u201cWe don\u2019t have detailed evaluations of everything at this point. But from our preliminary evaluations, everything is matching the models as well as we would expect the models to work at this point.\u201d<\/p>\n

The first three weeks of Webb\u2019s life in space were devoted to deploying its solar array and high-speed antenna, its secondary mirror, six of the primary mirror\u2019s 18 segments that were folded away for launch and extending a tennis court-size sunshade needed to block out the light and heat of the sun, Earth and moon.<\/p>\n

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This image mosaic was created by pointing the telescope at a bright, isolated star in the constellation Ursa Major known as HD 84406. This star was chosen specifically because it is easily identifiable and not crowded by other stars of similar brightness, which helps to reduce background confusion. An image from each of Webb\u2019s 18 primary mirror segments resulted in 18 individual light sources in this mosaic. Credit: NASA<\/figcaption><\/figure>\n

Then on Jan. 25, one month after launch, Webb reached its operational destination, slipping into orbit around Lagrange Point 2 a million miles away in deep space where it will circle the sun in gravitational lockstep with Earth, minimizing the amount of fuel needed to stay on station.<\/p>\n

All of that went off without a hitch and since then, engineers have been monitoring the telescope\u2019s optics and instruments as they cool down to the ultra-low, near-absolute-zero temperatures required to register faint light from the first stars and galaxies to form in the wake of the Big Bang.<\/p>\n

The low temperatures are required because space itself has expanded in the 13.8 billion years since the birth of the cosmos, stretching out that initial light into the infrared region of the spectrum. To \u201csee\u201d those objects, so far removed in space and time, Webb must be colder than the surrounding environment.<\/p>\n

The mirror segments are not yet at a uniform temperature. As of this week, the segment temperatures ranged from a \u201chigh\u201d of minus 349 Fahrenheit closest to the sunshade to a low of minus 379 degrees farther away. When fully cooled, engineers expect a maximum temperature spread of less than 10 degrees Fahrenheit.<\/p>\n

To align the mirror segments, ground controllers have aimed the telescope at a star 242 light years away near the bowl of the Big Dipper known as HD 84406. Using one of Webb\u2019s four instruments, the Near Infrared Camera, or NIRCam, the team began mapping out the reflections from each of the 18 primary mirror segments.<\/p>\n

\u201cAs planned, we pointed the telescope at a bright, isolated star, and we found and identified 18 spots for the 18 primary mirror segments,\u201d Feinberg said. \u201cAt this point, we\u2019ve been able to analyze multiple engineering images that help us understand the alignments and the mirrors themselves.<\/p>\n

\u201cAnd we don\u2019t see anything of concern. This is the first time we\u2019re getting data on mirrors that are actually at zero gravity and using starlight to illuminate the primary mirror. And again, so far the data is matching our models and expectations.\u201d<\/p>\n