{"id":849,"date":"2010-02-25T13:30:00","date_gmt":"2010-02-25T12:30:00","guid":{"rendered":"https:\/\/kids.esa.int\/mars_express_and_the_mystery_of_phobos\/"},"modified":"2026-10-08T00:32:58","modified_gmt":"2026-10-07T22:32:58","slug":"mars_express_and_the_mystery_of_phobos","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/mars_express_and_the_mystery_of_phobos\/","title":{"rendered":"Mars Express et le myst\u00e8re de Phobos"},"content":{"rendered":"<p>L\u2019orbiteur Mars Express de l\u2019ESA nous a envoy\u00e9 des images remarquables et des donn\u00e9es vari\u00e9es depuis son arriv\u00e9e \u00e0 destination en d\u00e9cembre 2003. Si la plan\u00e8te rouge reste le principal objectif de la sonde europ\u00e9enne, son orbite polaire l\u2019am\u00e8ne parfois \u00e0 proximit\u00e9 de Phobos, la plus grande des deux lunes de Mars. Au cours de la derni\u00e8re s\u00e9rie de survols s\u2019\u00e9chelonnant du 16 f\u00e9vrier au 26 mars, Mars Express \u00e9tablira un nouveau record en se rapprochant, le 3 mars, \u00e0 50 kilom\u00e8tres \u00e0 peine de la surface de Phobos. Les donn\u00e9es collect\u00e9es pendant ces survols rapproch\u00e9s pourraient nous aider \u00e0 r\u00e9soudre certains des myst\u00e8res qui entourent l\u2019\u00e9trange petit satellite martien.<\/p>\n<figure class=\"wp-block-image size-large\" data-width=\"2541\" data-credit=\"ESA\" data-detail-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2010\/01\/Mars_Express2\" data-licence=\"ESA Standard Licence\" data-licence-url=\"https:\/\/www.esa.int\/ESA_Multimedia\/Terms_and_conditions_of_use_of_images_and_videos_available_on_the_esa_website\"><img decoding=\"async\" loading=\"lazy\" style=\"max-width:100%;height:auto\" src=\"https:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2010\/01\/mars_express2\/17902345-2-eng-GB\/Mars_Express.jpg\" alt=\"Mars Express\"><figcaption>Mars Express<\/figcaption><\/figure>\n<p>Les images transmises par Mars Express et d\u2019autres sondes montrent que Phobos est un caillou de moins de 28 km de large qui ressemble un peu \u00e0 une pomme de terre. Elle suit une trajectoire \u00e9quatoriale pratiquement circulaire \u00e0 environ 6 000 km de la surface de la plan\u00e8te. Pour \u00e9viter de s\u2019\u00e9craser sur Mars, Phobos doit se d\u00e9placer tr\u00e8s rapidement sur son orbite. Chaque tour dure 7 heures et 39 minutes : une personne qui scruterait le ciel de Mars verrait passer Phobos d\u2019Ouest en Est trois fois par jour.<\/p>\n<p>La plupart des chercheurs pensent que ce petit caillou de l\u2019espace est un ast\u00e9ro\u00efde qui, arriv\u00e9 trop pr\u00e8s de Mars, a \u00e9t\u00e9 pi\u00e9g\u00e9 par la gravit\u00e9 de cette derni\u00e8re. Il est cependant difficile d\u2019expliquer comment Phobos a atteint son orbite actuelle. La plupart des lunes pi\u00e9g\u00e9es suivent, en effet, des orbites tr\u00e8s elliptiques (en forme d\u2019\u0153uf) \u00e9loign\u00e9es de leur plan\u00e8te. Mars Express pourrait nous aider \u00e0 lever le voile. \u00c9tudier la fa\u00e7on dont la gravit\u00e9 de Phobos agit sur la sonde et en modifie l\u2019orbite devrait permettre aux scientifiques d\u2019en apprendre davantage sur l\u2019int\u00e9rieur de cette lune. Les donn\u00e9es en notre possession jusqu\u2019\u00e0 maintenant ont port\u00e9 les chercheurs \u00e0 formuler l\u2019hypoth\u00e8se que Phobos pourrait \u00eatre un amas de roches poreuses comportant de nombreux espace vides.<\/p>","protected":false},"excerpt":{"rendered":"<p>ESA\u2019s Mars Express orbiter has been sending back remarkable images and other data since it reached the Red Planet in December 2003. Although Mars is its primary target, the spacecraft\u2019s [&hellip;]<\/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\/2009\/12\/phobos_up_close2\/17873150-2-eng-GB\/Phobos_up_close.jpg","esa_banner_description":"Phobos up close","esa_banner_credit":"ESA\/DLR\/FU Berlin (G. 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