{"id":841,"date":"2004-12-02T15:46:00","date_gmt":"2004-12-02T14:46:00","guid":{"rendered":"https:\/\/kids.esa.int\/expendable_or_reusable\/"},"modified":"2026-10-08T00:32:53","modified_gmt":"2026-10-07T22:32:53","slug":"expendable_or_reusable","status":"publish","type":"post","link":"https:\/\/kids.esa.int\/fi\/expendable_or_reusable\/","title":{"rendered":"Kertak\u00e4ytt\u00f6inen vai uudelleenk\u00e4ytett\u00e4v\u00e4?"},"content":{"rendered":"
\n

Aina kun eurooppalainen Ariane 5 -raketti laukaistaan Kourousta, sen rakettivaiheet putoavat mereen tai palavat ilmakeh\u00e4ss\u00e4. Ariane 5:n kaltaisia kantoraketteja kutsutaan \u2018kertak\u00e4ytt\u00f6isiksi\u2019.<\/p>\n<\/div>\n

Raketin h\u00e4vitt\u00e4minen jokaisen laukaisun yhteydess\u00e4 tuntuu tuhlaukselta ja kalliilta. Kustannuksia pidet\u00e4\u00e4n kuitenkin alhaisina valmistamalla raketteja sarjatuotantona. Niit\u00e4 valmistetaan kokoonpanolinjoilla \u2013 aivan kuten kalliita autoja.<\/p>\n

Kertak\u00e4ytt\u00f6iset raketit voivat my\u00f6s olla eritt\u00e4in luotettavia. Jos jokin niist\u00e4 ep\u00e4onnistuu laukaisun aikana, on melko helppo selvitt\u00e4\u00e4, mik\u00e4 meni vikaan, ja korjata vika.<\/p>\n

Toinen l\u00e4hestymistapa on rakentaa uudelleenk\u00e4ytett\u00e4v\u00e4 kantoraketti. T\u00e4h\u00e4n asti ainoa k\u00e4yt\u00f6ss\u00e4 ollut on ollut Yhdysvaltain avaruussukkula.<\/p>\n

Suurin osa Shuttle-orbiterin osista on suunniteltu kest\u00e4m\u00e4\u00e4n jopa 100 lentoa. My\u00f6s Shuttlen kiinte\u00e4n polttoaineen apuraketteja voidaan tarvittaessa k\u00e4ytt\u00e4\u00e4 uudelleen. Ainoastaan ulkoinen polttoaines\u00e4ili\u00f6 h\u00e4vitet\u00e4\u00e4n jokaisen lennon j\u00e4lkeen.<\/p>\n

Shuttlen rakentaminen ja lent\u00e4minen on kuitenkin eritt\u00e4in kallista. T\u00e4m\u00e4 johtuu p\u00e4\u00e4asiassa siit\u00e4, ett\u00e4 se on suunniteltu kuljettamaan jopa seitsem\u00e4\u00e4 miehist\u00f6n j\u00e4sent\u00e4. Sen on my\u00f6s kestett\u00e4v\u00e4 paluulennon \u00e4\u00e4rimm\u00e4inen kuumuus ja laskeuduttava kiitoradalle. Muita uudelleenk\u00e4ytett\u00e4vi\u00e4 kantoraketteja ei ole suunnitteilla, vaikka t\u00e4llaisten alusten tutkimusta jatketaan.<\/p>\n

ESA aikoo tarkastella molempia vaihtoehtoja huolellisesti, jotta lopulta voidaan tehd\u00e4 p\u00e4\u00e4t\u00f6s siit\u00e4, miten Ariane 5 korvataan.<\/p>","protected":false},"excerpt":{"rendered":"

Every time Europe\u2019s Ariane 5 lifts off from Kourou, its rocket stages fall into the ocean or burn up in the atmosphere. Launchers such as Ariane 5 are said to […]<\/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\/2000\/08\/atmospheric_re-entry_demonstrator_-_artist_s_impression2\/17866009-3-eng-GB\/Atmospheric_Re-entry_Demonstrator_-_artist_s_impression.jpg","esa_banner_description":"Atmospheric Re-entry Demonstrator - artist's impression","esa_banner_credit":"ESA - D.Ducros","esa_banner_licence":"ESA Standard Licence","esa_banner_detail_url":"https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2000\/08\/Atmospheric_Re-entry_Demonstrator_-_artist_s_impression2","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":[10,41,40],"tags":[2],"panel":[],"language":[],"age":[],"duration":[],"resource_type":[],"audience":[],"wf_post_folders":[],"class_list":["post-841","post","type-post","status-publish","format-standard","hentry","category-learn","category-rockets-technology","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\/841","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=841"}],"version-history":[{"count":1,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/841\/revisions"}],"predecessor-version":[{"id":1984,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/posts\/841\/revisions\/1984"}],"wp:attachment":[{"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/media?parent=841"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/categories?post=841"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/tags?post=841"},{"taxonomy":"panel","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/panel?post=841"},{"taxonomy":"language","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/language?post=841"},{"taxonomy":"age","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/age?post=841"},{"taxonomy":"duration","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/duration?post=841"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/resource_type?post=841"},{"taxonomy":"audience","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/audience?post=841"},{"taxonomy":"wf_post_folders","embeddable":true,"href":"https:\/\/kids.esa.int\/fi\/wp-json\/wp\/v2\/wf_post_folders?post=841"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}