{"id":33345,"date":"2023-03-13T02:33:45","date_gmt":"2023-03-12T21:03:45","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=33345"},"modified":"2025-04-19T21:29:39","modified_gmt":"2025-04-19T15:59:39","slug":"controlled-re-entry-of-satellites-isro-brings-down-weather-satellite-megha-tropiques-1","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/controlled-re-entry-of-satellites-isro-brings-down-weather-satellite-megha-tropiques-1\/","title":{"rendered":"Controlled re-entry of satellites: ISRO brings down weather satellite Megha Tropiques-1"},"content":{"rendered":"<h3><strong>What\u2019s in today\u2019s article?<\/strong><\/h3>\n<ul>\n<li><strong>Why in News?<\/strong><\/li>\n<li><strong>What Happens to Satellites after their Life ends?<\/strong><\/li>\n<li><strong>How ISRO Brought Down the Satellite?<\/strong><\/li>\n<li><strong>Why did ISRO Attempt a Controlled Re-entry?<\/strong><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h2><strong>Why in News?<\/strong><\/h2>\n<ul>\n<li>The Indian Space Research Organisation (ISRO)<strong> for the first time <\/strong>brought down a satellite &#8211; Megha Tropiques-1, <strong>in a controlled manner <\/strong>after its end of life.<\/li>\n<li>Although the mission life of the weather satellite &#8211; a joint India-France mission launched aboard a <strong>PSLV <\/strong>in <strong>2011<\/strong>, was only 3 years, it continued providing data on water cycle, energy exchanges in the tropics for nearly a decade.<\/li>\n<\/ul>\n<p><strong>\u00a0<\/strong><\/p>\n<h2><strong>What Happens to Satellites after their Life ends?<\/strong><\/h2>\n<ul>\n<li>Usually, satellites are left in their orbit and because of the<strong> gravitational pull of the earth<\/strong>, they come down to the atmosphere over years and years.<\/li>\n<li>It takes debris from the low earth orbit <strong>20 to 30 years<\/strong> to fall to the atmosphere and <strong>generations <\/strong>for those in geosynchronous or geo-stationary orbits to fall.\n<ul>\n<li>When the satellites re-enter the atmosphere, <strong>the friction causes<\/strong> it to heat up to extreme high temperatures of thousands of degrees Celsius.<\/li>\n<li>Without a heat shield, <strong>99% of a satellite gets burnt up<\/strong> whether in a controlled re-entry or an uncontrolled one.<\/li>\n<\/ul>\n<\/li>\n<li>A controlled re-entry is possible <strong>only for satellites in low-earth orbit<\/strong> &#8211; at about 1,000 kms over the surface of the earth.\n<ul>\n<li>These manoeuvres, however, <strong>are not usually attempted<\/strong> because fuel reserves have to be maintained in the satellite after mission life is over.<\/li>\n<\/ul>\n<\/li>\n<li>This is<strong> impossible for satellites placed in geo-stationary or geosynchronous orbit<\/strong> &#8211; where time taken by the satellite to orbit the earth matches Earth\u2019s rotation &#8211; because they are at altitudes of nearly <strong>36,000 kms.<\/strong>\n<ul>\n<li>For attempting to bring down a satellite from such an orbit, <strong>a huge fuel reserve would be needed<\/strong>, which will only make the satellite heavier and costlier at launch.<\/li>\n<li>Therefore, instead of bringing them down, <strong>they are shot upwards at the end of life<\/strong>. These orbits are like parking lots in space where all old satellites are put in.<\/li>\n<li>Sometimes a satellite might escape to <strong>deep space<\/strong> (when its velocity increases enough to get away from the gravitational pull of the earth) as well.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h2><strong>How ISRO Brought Down the Satellite?<\/strong><\/h2>\n<ul>\n<li>This was the<strong> first time<\/strong> that the space agency attempted such a manoeuvre to clear out space debris <strong>despite the satellite not being built to do so.<\/strong><\/li>\n<li><strong>With over 120kgs of fuel remaining<\/strong> in the satellite even after being decommissioned, the space agency attempted a controlled re-entry.<\/li>\n<li>A series of <strong>20 manoeuvres over eight months<\/strong> lowered the orbit of the satellite such that it re-entered the dense atmosphere and burnt up over the Pacific Ocean.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<h2><strong>Why did ISRO Attempt a Controlled Re-entry?<\/strong><\/h2>\n<ul>\n<li>Other than extra fuel remaining in the satellite after the mission life ended, ISRO attempted the control re-entry<strong> to demonstrate and understand the process of doing so.<\/strong><\/li>\n<li>With several satellites\/other objects\/debris moving at extremely high speeds in low earth orbits, <strong>it has become imperative to keep the space clean <\/strong>as even the smallest debris can destroy active satellites.<\/li>\n<li><strong>Kessler syndrome<\/strong> &#8211; a scenario where the amount of space debris reaches a point where they just create more with one collision triggering others &#8211; is even scarier.<\/li>\n<li><strong>This is the reason space debris<\/strong> is monitored and sometimes satellites have to be moved from their way.<\/li>\n<li><strong>For example,<\/strong> ISRO carried out 21 such collision course manoeuvres in 2022 and set up a department last year to monitor the space debris and mitigate the risks posed.<\/li>\n<li>The space agency was also following the guidelines of <strong>UN and the Inter-Agency Space Debris Coordination Committee (IADC)<\/strong> that say satellites should be deorbited after mission life.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/lh5.googleusercontent.com\/wZNqaNpOOrCrNqgar0oPy4a3js0vr8Cvp7das9zQ0vL1tgq3rvZU6jfcHOYIdnQIO4-MGVR4YhM0PV1aRHLwIIesvP_Tf1oYZIY6mY879w1BWfZlTvkAJ6DACf6lC-TpLN3qp8vAkPrz\" alt=\"\" \/><\/p>\n<p>Image Caption: Space Junk by Numbers<\/p>\n<p>&nbsp;<\/p>\n<hr \/>\n<h3><strong>Q1) What is Megha-Tropiques-1 (MT1)?<\/strong><\/h3>\n<p>It was a satellite launched in 2011, as a collaborative effort between ISRO and the French space agency CNES for carrying out tropical weather and climate studies. The controlled re-entry experiment for the decommissioned MT-1 was carried out successfully recently.<\/p>\n<p><strong>\u00a0<\/strong><\/p>\n<h3><strong>Q2) What is IS4OM?<\/strong><\/h3>\n<p>ISRO System for Safe and Sustainable Space Operations Management (IS4OM) is a holistic approach launched in response to ever-growing space object population and the risk of collisions in space and undertakes observation and monitoring of space objects and space environment.<\/p>\n<p>&nbsp;<\/p>\n<hr \/>\n<p><strong>Source:\u00a0<\/strong><a href=\"https:\/\/indianexpress.com\/article\/explained\/explained-sci-tech\/isro-brings-down-weather-satellite-controlled-re-entry-8489195\/\" target=\"_blank\" rel=\"nofollow noopener\"><u>Isro brings down decommissioned weather satellite: What is a controlled re-entry? Why is it done?<\/u><\/a>\u00a0|\u00a0<a href=\"https:\/\/indianexpress.com\/article\/explained\/space-debris-from-indian-satellite-nasa-worry-and-why-risk-is-low-5655449\/\" target=\"_blank\" rel=\"nofollow noopener\"><u>IE<\/u><\/a><\/p>\n<p><strong>Video:\u00a0<\/strong><a href=\"https:\/\/www.youtube.com\/watch?v=YEby2ioHRHM\" target=\"_blank\" rel=\"nofollow noopener\"><u>https:\/\/www.youtube.com\/watch?v=YEby2ioHRHM<\/u><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A controlled re-entry is possible only for satellites in low-earth orbit &#8211; at about 1,000 kms over the surface of the earth<\/p>\n","protected":false},"author":5,"featured_media":33346,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[18],"tags":[],"class_list":{"0":"post-33345","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-mains-current-affairs","8":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/33345","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=33345"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/33345\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/33346"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=33345"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=33345"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=33345"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}