The Collaborative International Dictionary
Space age \Space age\, n. the time during which humans engaged in space exploration; -- generally considered as beginning on October 4, 1957 when the Soviet Union placed the first artificial satellite into orbit around the earth.
Wiktionary
alt. 1 The period from the about the time of the launch of http://en.wikipedia.org/wiki/Sputnik in 1957 to the present day, during which man ventured into space. 2 (context attributive English) Redolent of the space age; appearing futuristic or modern. n. 1 The period from the about the time of the launch of http://en.wikipedia.org/wiki/Sputnik in 1957 to the present day, during which man ventured into space. 2 (context attributive English) Redolent of the space age; appearing futuristic or modern.
WordNet
n. the age beginning with the first space travel; from 1957 to the present
Wikipedia
The Space Age is a time period encompassing the activities related to the Space Race, space exploration, space technology, and the cultural developments influenced by these events. The Space Age is generally considered to have begun with Sputnik (1957).
Usage examples of "space age".
There lay the first two generations of the Space Age, spanning twenty miles of the Florida coast to the south, outlined by winking red warning lights, were the giant gantries of the Saturns and Neptunes, that had set men on the path to the planets, and had now passed into history.
However, he was flattered to discover how well-acquainted they were with Discovery's log, it had become one of the classic records of the Space Age.