{"id":791679,"date":"2024-12-03T08:26:00","date_gmt":"2024-12-03T13:26:00","guid":{"rendered":"http:\/\/spaceweekly.com\/?p=791679"},"modified":"2024-12-03T08:26:00","modified_gmt":"2024-12-03T13:26:00","slug":"a-sun-observing-telescope-made-from-2-satellites","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=791679","title":{"rendered":"A sun-observing telescope made from 2 satellites"},"content":{"rendered":"<p> <br \/>\n<\/p>\n<div>\n<figure id=\"attachment_494300\" aria-describedby=\"caption-attachment-494300\" style=\"width: 800px\" class=\"wp-caption alignnone\"><figcaption id=\"caption-attachment-494300\" class=\"wp-caption-text\">An illustration of the 2-part Proba-3 spacecraft, set to launch on December 4, 2024. The pair of satellites will be aligned so that one satellite blocks the sun\u2019s glare for the other. This will allow the second satellite to image the sun\u2019s otherwise invisible atmosphere. Artist\u2019s impression via ESA\/ P. Carril.<\/figcaption><\/figure>\n<p>On December 4, 2024, ESA is set to launch an audacious two-part telescope into space to study the sun\u2019s atmosphere. <\/p>\n<p>If you\u2019ve ever seen a total solar eclipse, you\u2019ll have caught a glimpse of this wispy outer atmosphere, called the <em>corona<\/em>. With the moon eclipsing the dazzling body of the sun, this faint light streaming from our star suddenly becomes visible. And coronagraphs \u2013 telescopes that study the sun\u2019s atmosphere \u2013 work the same way. They block out the sun\u2019s glare with a disk called an <em>occulter<\/em> attached to the front of the telescope. <\/p>\n<p>But ESA\u2019s new spacecraft, Proba-3, isn\u2019t like any other coronagraph. The occulter isn\u2019t attached to the telescope \u2026 but will instead be on a separate satellite, 492 feet (150 meters) away. Soaring through space in perfect coordination, the two spacecraft will form the largest coronagraph ever made. <\/p>\n<p>This new instrument is set to launch from Satish Dhawan Space Centre in Sriharikota, India, on December 4, at 10:38 UTC. <\/p>\n<p>The 2025 EarthSky lunar calendar makes a great gift. Get yours today!<\/p>\n<p><iframe loading=\"lazy\" title=\"Proba-3: A Ground-Breaking 2-Part Space Telescope!\" width=\"1110\" height=\"624\" src=\"https:\/\/www.youtube.com\/embed\/8W9jE0FaZm8?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><br \/><em>EarthSky\u2019s Will Triggs explains the ground-breaking Proba-3 mission in this short video.<\/em><\/p>\n<h3>Proba-3, reinventing the coronagraph<\/h3>\n<p>Scientists have been using coronagraphs to study the sun for almost a century, with French astronomer Bernard Lyot building the first in 1931. Since then we\u2019ve sent several coronagraphs into space, in order to image the sun without the distortion of Earth\u2019s atmosphere. So what\u2019s the need for this unique two-part coronagraph?<\/p>\n<p>Damien Galano, Proba-3\u2019s mission manager, explained:<\/p>\n<blockquote>\n<p>[Designing a coronagraph] might sound simple, but it\u2019s rendered much harder by the peculiar fact that light acts as both particles and waves. This means some light spills around the edge of whatever\u2019s blocking it, like waves around a seawall. This phenomenon is known as <em>diffraction<\/em>; it needs to be designed against to minimize unwanted sunlight reaching your instrument.<\/p>\n<\/blockquote>\n<p>And the best way to avoid diffraction? Move the occulting disk farther from the telescope. As Andrei Zhukov, Principal Investigator of Proba-3\u2019s main instrument, explained:<\/p>\n<blockquote>\n<p>This is why total solar eclipses give us such an excellent view of the corona, because the moon is around 238,000 miles (384,000 kilometers) away from Earth, so diffraction effects are minimal.<\/p>\n<\/blockquote>\n<p>But a large distance between telescope and the occulter is hard to achieve on a single spacecraft. The LASCO C2 coronagraph on NASA\u2019S SOHO spacecraft \u2013 which we often rely on for our daily sun news updates \u2013 has its occulter just 70 centimeters (28 inches) away. <\/p>\n<p>It was to overcome this limitation that, two decades ago, scientists at the Laboratoire d\u2019Astrophysique de Marseille came up with Proba-3\u2019s system, in which an entirely separate spacecraft occults the sun from afar.<\/p>\n<figure id=\"attachment_494309\" aria-describedby=\"caption-attachment-494309\" style=\"width: 512px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/11\/lasco-c2-nov25-26.gif\" alt=\"Red tinted view of space with plain red circle in the middle obscuring the sun. Bright white and orange whisps fly out from the sides of the circle. \" width=\"512\" height=\"512\" class=\"size-full wp-image-494309\"\/><figcaption id=\"caption-attachment-494309\" class=\"wp-caption-text\">This is the familiar perspective of the SOHO spacecraft\u2019s LASCO C2 coronagraph. This clip shows coronal activity from November 25-26, 2024. Image via NASA.<\/figcaption><\/figure>\n<h3>The fantastic feat of formation flying<\/h3>\n<p>To function as a coronagraph, the pair of satellites that make up Proba-3 will have to successfully perform what ESA is calling the \u2018world\u2019s first precision formation flying mission\u2019.<\/p>\n<p>The satellites will launch together and then separate into tandem orbits around Earth. These 19.7-hour orbits will be highly elliptical, bringing them just 373 miles (600 kilometers) away at perigee \u2013 their closest to Earth \u2013 and 37,612 miles (60,530 kilometers) away at apogee, their farthest from Earth. <\/p>\n<p>And during apogee, when Earth\u2019s gravitational pull is weaker and requires less fuel, the satellites will maneuver into formation. They\u2019ll line up 492 feet (150 meters) apart, so that the outer spacecraft\u2019s 4.6 feet (1.4 meter) occulting disk creates an artificial solar eclipse for the inner satellite. <\/p>\n<p>To keep the eclipse stable, they\u2019ll maintain their separation to a precise single millimeter. The spacecraft will do this autonomously, communicating with each other via LEDs and lasers. A shadow detector on the telescope satellite will make corrections if the occulting satellite\u2019s 3 inch (8 centimeters) shadow is in any way misaligned. And they\u2019ll maintain this precise positioning for six hours at a time.<\/p>\n<figure id=\"attachment_494213\" aria-describedby=\"caption-attachment-494213\" style=\"width: 600px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/11\/Proba-3-animation-alignment-november-2024.gif\" alt=\"Animation with yellow sun on the left and the two Proba-3 satellites on the right. The furthest right drops into the shadow of the one in the middle of the screen, forming a perpendicular line to the sun.\" width=\"600\" height=\"338\" class=\"size-full wp-image-494213\"\/><figcaption id=\"caption-attachment-494213\" class=\"wp-caption-text\">The spacecraft won\u2019t always be aligned, because this would require too much fuel. Instead, they\u2019ll use their thrusters to maneuver into position for 6 hours at a time when required. Animation via ESA.<\/figcaption><\/figure>\n<h3>Proba-3 will provide a unique view of the sun<\/h3>\n<p>The increased distance between Proba-3\u2019s telescope and its occulter will allow it to see much closer to the edge of our star without bright sunlight bleeding into the image. Proba-3 will be able to see the corona from just 1.1 times the radius of the solar disk. For contrast, LASCO C2\u2019s field of view starts at 1.5 times the solar radius. <\/p>\n<p>So scientists using Proba-3 will be able to see the sun\u2019s inner corona, which is normally visible only during a total solar eclipse. Total solar eclipses only occur an average of once every 18 months, and typically last under seven minutes. But Proba-3 will be able to study the inner corona for six hours at a time around 50 times a year.<\/p>\n<p>And it will study this region with a better frame rate (number of frames per second) than other space-based coronagraphs. While LASCO C2 takes an image roughly every 12 minutes, Proba-3 can image the corona up to every 30 seconds. <\/p>\n<p>Scientists hope this detailed view of the inner corona will provide insight into the development of coronal mass ejections (CMEs): blobs of solar material and magnetic fields blasted out during events on the sun. CMEs can cause auroras if they reach Earth, as they disturb our magnetic field. And particularly strong CMEs can pose a threat to satellites and even power grids on Earth.<\/p>\n<figure id=\"attachment_494303\" aria-describedby=\"caption-attachment-494303\" style=\"width: 800px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/earthsky.org\/upl\/2024\/11\/proba-3-earth-in-background.jpg\" alt=\"Illustration of the top 2 thirds of Earth from space, with two satellites in a line in the foreground. The one closer to the viewer has a solar panel shining with sunlight.\" width=\"800\" height=\"600\" class=\"size-full wp-image-494303\" srcset=\"https:\/\/earthsky.org\/upl\/2024\/11\/proba-3-earth-in-background.jpg 800w, https:\/\/earthsky.org\/upl\/2024\/11\/proba-3-earth-in-background-300x225.jpg 300w, https:\/\/earthsky.org\/upl\/2024\/11\/proba-3-earth-in-background-768x576.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\"\/><figcaption id=\"caption-attachment-494303\" class=\"wp-caption-text\">Proba-3 will be in an extremely elliptical orbit around Earth. And when the satellites reach their furthest from Earth, they will maneuver into position to form an artificial total solar eclipse. Artist\u2019s impression via ESA\/ P. Carril.<\/figcaption><\/figure>\n<h3>A new look at the corona, coming soon<\/h3>\n<p>Observations with Proba-3 are set to begin after a roughly four-month commissioning stage. And the team currently plans to have two six-hour observing periods every week, depending on how much fuel needs to be saved across the planned two years of operation. <\/p>\n<p>Proba-3 is an ambitious innovation, which ESA describes as a \u201ctechnology demonstration mission\u201d. And if all goes to plan, it should be a useful tool in scientists\u2019 growing sun-observing arsenal. Mission scientist Joe Zender said:<\/p>\n<blockquote>\n<p>Success will rely on the formation flying technology working as planned, of course, but the closer we get to launch, the more I realize the excitement of what we are doing, including co-observations with many other solar observing missions.<\/p>\n<\/blockquote>\n<p>Bottom line: ESA is launching an ambitious spacecraft to study the sun\u2019s atmosphere. Proba-3 is comprised of 2 satellites that will align to form an artificial solar eclipse.<\/p>\n<p>Via ESA<\/p>\n<p>Read more: Why is the sun\u2019s atmosphere hotter than its surface?<\/p>\n<p><span class=\"cp-load-after-post\"\/><\/div>\n<div>\n<div class=\"post-author\">\n<h4>Will Triggs<\/h4>\n<p>                    View Articles\n                  <\/p><\/div>\n<div class=\"post-tags\">\n<h6 data-udy-fe=\"text_7c58270d\">About the Author:<\/h6>\n<p>Will Triggs joined EarthSky to work on our daily newsletter, but he has since become a popular presenter of space news on our YouTube channel.  He fell in love with stargazing after moving to Norfolk on England&#8217;s east coast, where the dark skies allowed him to catch a glimpse of the Milky Way for the first time. Having joined EarthSky after completing degrees in English and Creative Writing, he is passionate about communicating the beauty and importance of what&#8217;s around us, and what&#8217;s above us.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<p><br \/>\n<br \/><a href=\"https:\/\/earthsky.org\/space\/proba-3-a-sun-observing-telescope-made-from-2-satellites\/?rand=772280\">Source link <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>An illustration of the 2-part Proba-3 spacecraft, set to launch on December 4, 2024. The pair of satellites will be aligned so that one satellite blocks the sun\u2019s glare for&hellip; <\/p>\n","protected":false},"author":1,"featured_media":791680,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[],"class_list":["post-791679","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earth-sky"],"_links":{"self":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/791679","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=791679"}],"version-history":[{"count":0,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/791679\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/media\/791680"}],"wp:attachment":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=791679"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=791679"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=791679"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}