{"id":820,"date":"2004-12-02T15:35:00","date_gmt":"2004-12-02T14:35:00","guid":{"rendered":"https:\/\/kids.esa.int\/gravity_assists\/"},"modified":"2026-10-08T00:32:39","modified_gmt":"2026-10-07T22:32:39","slug":"gravity_assists","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fr\/gravity_assists\/","title":{"rendered":"Assistance gravitationnelle"},"content":{"rendered":"
\n

Comme vous le savez, une voiture a tendance \u00e0 ralentir lorsqu\u2019elle monte une c\u00f4te et \u00e0 acc\u00e9l\u00e9rer lorsqu\u2019elle descend. On peut dire que la voiture b\u00e9n\u00e9ficie d\u2019une \u2018 aide gravitationnelle \u2019, puisque la gravit\u00e9 terrestre l\u2019aide \u00e0 ralentir ou \u00e0 acc\u00e9l\u00e9rer. De la m\u00eame mani\u00e8re, un vaisseau spatial peut profiter d\u2019un \u00ab coup de pouce \u00bb sans avoir \u00e0 utiliser de pr\u00e9cieux carburants.<\/p>\n<\/div>\n

Une man\u0153uvre d'assistance gravitationnelle se produit lorsqu'un vaisseau spatial passe \u00e0 proximit\u00e9 d'une plan\u00e8te ou d'une grande lune. La gravit\u00e9 de la plan\u00e8te exerce alors une attraction sur le vaisseau spatial, ce qui modifie son orbite.<\/p>\n

Parfois, le vaisseau spatial acc\u00e9l\u00e8re, parfois il ralentit, selon qu\u2019il passe derri\u00e8re ou devant la plan\u00e8te. L\u2019assistance gravitationnelle modifie \u00e9galement la direction dans laquelle le vaisseau spatial se d\u00e9place.<\/p>\n

L'une des man\u0153uvres d'assistance gravitationnelle les plus spectaculaires a \u00e9t\u00e9 utilis\u00e9e dans le cadre de la mission Ulysses de l'ESA. En survolant le p\u00f4le nord de Jupiter, Ulysses a \u00e9t\u00e9 propuls\u00e9 sur une orbite qui l'a conduit au-dessus des p\u00f4les du Soleil.<\/p>\n

La mission Cassini-Huygens a utilis\u00e9 quatre assistances gravitationnelles (une de la terre, deux de V\u00e9nus et une de Jupiter) dans son p\u00e9riple vers Saturne.<\/p>\n

La gravit\u00e9 a aussi jou\u00e9 un r\u00f4le dans la mission SMART-1 de l\u2019ESA. Apr\u00e8s une trajectoire en spirale s\u2019\u00e9loignant r\u00e9guli\u00e8rement de la terre durant 14 mois, l\u2019engin spatial a commenc\u00e9 \u00e0 ressentir les effets de l\u2019attraction de la lune. En novembre 2004, SMART-1 a \u00e9t\u00e9 captur\u00e9 par l\u2019attraction de la lune et est entr\u00e9 en orbite autour d\u2019elle.<\/p>","protected":false},"excerpt":{"rendered":"

As you know, a car tends to slow down when it goes up a mountain and to accelerate when it is going downhill. One can say that the car is […]<\/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\/2003\/08\/ulysses_and_the_heliosphere2\/17889541-2-eng-GB\/Ulysses_and_the_heliosphere.jpg","esa_banner_description":"Ulysses and the heliosphere","esa_banner_credit":"ESA (image by D. Hardy)","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2003\/08\/Ulysses_and_the_heliosphere2","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":[10,65,40],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-820","post","type-post","status-publish","format-standard","hentry","category-learn","category-mission-control","category-technology","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/820","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=820"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/820\/revisions"}],"predecessor-version":[{"id":1963,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/posts\/820\/revisions\/1963"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/media?parent=820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/categories?post=820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/tags?post=820"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/panel?post=820"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/language?post=820"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/age?post=820"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/duration?post=820"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/resource_type?post=820"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/audience?post=820"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fr\/wp-json\/wp\/v2\/wf_post_folders?post=820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}