{"id":1140,"date":"2004-11-19T09:43:00","date_gmt":"2004-11-19T08:43:00","guid":{"rendered":"https:\/\/kids.esa.int\/sailing_through_space\/"},"modified":"2026-10-09T11:30:53","modified_gmt":"2026-10-09T09:30:53","slug":"sailing_through_space","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/sailing_through_space\/","title":{"rendered":"Purjehtiminen avaruudessa"},"content":{"rendered":"
\n

T\u00e4h\u00e4n asti l\u00e4hes kaikissa avaruuslennoissa on k\u00e4ytetty kemiallista polttoainetta k\u00e4ytt\u00e4vi\u00e4 rakettimoottoreita. Valitettavasti ne eiv\u00e4t ole kovin tehokkaita. Esimerkiksi yli puolet ESA:n Rosetta-avaruusluotaimen laukaisupainosta koostui polttoaineesta.<\/p>\n<\/div>\n

ESA tutkii parhaillaan keinoja v\u00e4hent\u00e4\u00e4 mukana kuljetettavan polttoaineen m\u00e4\u00e4r\u00e4\u00e4. Yksi vaihtoehto on ionimoottori, joka k\u00e4ytt\u00e4\u00e4 s\u00e4hk\u00f6ist\u00e4 \u2018pistoolia\u2019 kaasun ampumiseen avaruuteen.<\/p>\n

Vaikka moottorin eteenp\u00e4in suuntautuva ty\u00f6nt\u00f6voima on hyvin v\u00e4h\u00e4inen, se kasvattaa nopeutta v\u00e4hitellen. Lopulta se mahdollistaa avaruusaluksen eritt\u00e4in nopean liikkumisen.<\/p>\n

\"Artist's
Taiteilijan n\u00e4kemys SMART-1:st\u00e4<\/figcaption><\/figure>\n

SMART-1-luotain testasi ionimoottoria menestyksekk\u00e4\u00e4sti matkallaan Kuuhun. Moottori tuotti 10 kertaa enemm\u00e4n ty\u00f6nt\u00f6voimaa kuin tavallinen rakettimoottori jokaista k\u00e4ytetty\u00e4 polttoainekiloa kohti.<\/p>\n

ESA tutkii my\u00f6s avaruusaluksia, joissa k\u00e4ytet\u00e4\u00e4n aurinkopurjeita moottoreiden sijaan. Suureen, peilim\u00e4iseen purjeeseen osuva auringonvalo pystyy ty\u00f6nt\u00e4m\u00e4\u00e4n avaruusaluksen kohti muita planeettoja. Useiden kuukausien kuluttua t\u00e4llainen avaruusalus voisi saavuttaa 360 000 km\/h:n nopeuden.<\/p>\n

Toinen tapa s\u00e4\u00e4st\u00e4\u00e4 polttoainetta ja painoa on hidastaa vauhtia lent\u00e4m\u00e4ll\u00e4 planeetan yl\u00e4ilmakeh\u00e4n l\u00e4pi. ESA aikoo rakentaa avaruusaluksen, joka siirtyy Marsin kiertoradalle t\u00e4m\u00e4n \u2018aerocapture\u2019-menetelm\u00e4n avulla.<\/p>","protected":false},"excerpt":{"rendered":"

Until now, nearly all space missions have used rocket motors that feed on chemical fuel. Unfortunately, these are not very efficient. For example, over half the launch weight of ESA’s […]<\/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\/04\/close-up_view_of_smart-1_s_stationary_plasma_thruster2\/17900310-2-eng-GB\/Close-up_view_of_SMART-1_s_stationary_plasma_thruster.jpg","esa_banner_description":"Close-up view of SMART-1's stationary plasma thruster","esa_banner_credit":"ESA 2002. Illustration by Medialab.","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2003\/04\/Close-up_view_of_SMART-1_s_stationary_plasma_thruster2","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":[10,44,40],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-1140","post","type-post","status-publish","format-standard","hentry","category-learn","category-spacecraft","category-technology","tag-background-article"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1140","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/comments?post=1140"}],"version-history":[{"count":4,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1140\/revisions"}],"predecessor-version":[{"id":4867,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/1140\/revisions\/4867"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=1140"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=1140"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=1140"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=1140"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=1140"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=1140"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=1140"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=1140"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=1140"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=1140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}