🌐EnglishEnglishFrançaisItalianoNederlandsPolskiPortuguêsTiếng ViệtTürkçeРусский日本語EntityQ49897· pop 10· linked from 179 articlesExplorer 9Also known as S-56AAmerican satelliteWikidata factsImageExplorer 9.jpgSources (1)wikidata.orgvia Wikidata · CC0Available in 9 languages日本語PortuguêsItalianoCzechGalicianPolskiSlovakTürkçevia Wikidata sitelinks · CC0ConnectionsExplorers ProgramEntitydensity of airEntityCategoriesBalloon satellitesExplorers ProgramGeospace monitoring satellitesPassive satellitesSatellites in medium Earth orbitSource attributionSpacecraft launched in 1961Spacecraft which reentered in 1964