A thoroughly revised second edition of the 1958 "Que sais-je?" classic. Martin abandons the chronological narrative of the first launches to adopt a thematic plan spanning seven years of the space age (1957–1965): orbital mechanics, physical evolution of satellites, orbital injection techniques illustrated by the Vanguard and Saturn rockets, a survey of landmark satellites (Sputniks, Vanguard I "Grapefruit," Echo, West Ford, Elektron), and (the central contribution over the first edition) a chapter covering scientific satellites, telecommunications relays (Telstar, Relay, Syncom), and the first crewed spaceflights, from Gagarin to the spacewalks of Leonov and Ed White in 1965.