{"id":624,"date":"2013-09-19T09:25:00","date_gmt":"2013-09-19T07:25:00","guid":{"rendered":"https:\/\/kids.esa.int\/re-entry_nears_for_esa_s_ferrari_of_space\/"},"modified":"2026-10-08T00:30:24","modified_gmt":"2026-10-07T22:30:24","slug":"re-entry_nears_for_esa_s_ferrari_of_space","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/re-entry_nears_for_esa_s_ferrari_of_space\/","title":{"rendered":"La rentr\u00e9e atmosph\u00e9rique approche pour la \u2018 Ferrari de l'espace \u2019 de l'ESA\u2019"},"content":{"rendered":"
\n

Apr\u00e8s plus de quatre ann\u00e9es en orbite, la mission GOCE de l\u2019ESA touche \u00e0 sa fin. \u00c0 la mi-octobre, le satellite de l\u2019ESA n\u2019aura plus de carburant et son orbite va d\u00e9cliner. Sa rentr\u00e9e dans l\u2019atmosph\u00e8re aura lieu environ trois semaines plus tard.<\/p>\n<\/div>\n

Lanc\u00e9 en mars 2009, GOCE \u00e9tait plac\u00e9 sur une orbite basse de 270 km, plut\u00f4t inhabituelle pour un satellite scientifique. Sa mission consistait \u00e0 cartographier avec une pr\u00e9cision in\u00e9gal\u00e9e les plus infimes variations de la gravit\u00e9 terrestre.<\/p>\n

La gravit\u00e9 est la force qui attire tout corps mat\u00e9riel vers le sol. Cependant, la force gravitationnelle de la Terre peut l\u00e9g\u00e8rement varier d\u2019un endroit \u00e0 l\u2019autre, notamment car notre plan\u00e8te n\u2019est pas parfaitement ronde et se trouve l\u00e9g\u00e8rement aplatie aux p\u00f4les. La gravit\u00e9 est \u00e9galement affect\u00e9e par les hautes montagnes et les fosses sous-marines, ainsi que par l\u2019\u00e9paisseur et la densit\u00e9 des oc\u00e9ans et des couches rocheuses.<\/p>\n

\"New
Nouveau g\u00e9o\u00efde GOCE<\/figcaption><\/figure>\n

Quand GOCE survole des r\u00e9gions de diff\u00e9rentes forces gravitationnelles, l\u2019appareil monte ou descend et ses instruments enregistrent chaque changement de trajectoire. La pr\u00e9cision des donn\u00e9es qu\u2019il recueille provient en grande partie de son orbite basse et de sa forme allong\u00e9e et a\u00e9rodynamique, qui lui a valu le surnom de \u00ab Ferrari de l\u2019espace \u00bb. Ce satellite unique est \u00e9galement extr\u00eamement stable, et ne comporte aucune des pi\u00e8ces mobiles que l\u2019on retrouve g\u00e9n\u00e9ralement sur les autres satellites.<\/p>\n

Les donn\u00e9es transmises par GOCE ont permis d\u2019\u00e9tudier les courants oc\u00e9aniques, la variation du niveau des oc\u00e9ans, l\u2019altitude de la surface terrestre et la structure stratifi\u00e9e de la cro\u00fbte rocheuse de la Terre. GOCE a \u00e9galement d\u00e9tect\u00e9 des traces de vent solaire ainsi que les ondes acoustiques \u00e9mises dans l'atmosph\u00e8re apr\u00e8s le violent s\u00e9isme qui a frapp\u00e9 le Japon le 11 mars 2011. Mais le r\u00e9sultat le plus important de cette mission est sans conteste d\u2019avoir r\u00e9ussi \u00e0 \u00e9laborer un mod\u00e8le plus pr\u00e9cis du g\u00e9o\u00efde (la repr\u00e9sentation de r\u00e9f\u00e9rence de la gravit\u00e9 terrestre). Le g\u00e9o\u00efde repr\u00e9sente l\u2019apparence de la Terre si tous ses points \u00e9taient soumis \u00e0 la m\u00eame gravit\u00e9. Dans cette configuration, l\u2019eau ne pourrait donc pas y couler.<\/p>","protected":false},"excerpt":{"rendered":"

After more than four years in orbit, ESA\u2019s GOCE mission is nearing its end. In mid-October, the satellite will run out of fuel and its orbit will begin to decay. […]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"esa_banner_image":"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2008\/03\/goce_in_orbit4\/18246217-2-eng-GB\/GOCE_in_orbit.jpg","esa_banner_description":"GOCE in orbit","esa_banner_credit":"ESA\/AOES Medialab","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2008\/03\/GOCE_in_orbit4","esa_external_url":"","esa_external_new_window":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":true},"categories":[26],"tags":[],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-624","post","type-post","status-publish","format-standard","hentry","category-news"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/624","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/comments?post=624"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/624\/revisions"}],"predecessor-version":[{"id":4591,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/624\/revisions\/4591"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=624"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=624"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=624"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=624"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=624"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=624"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=624"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=624"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=624"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=624"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}