space age

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The period after 1957, the year in which a spacecraft was first placed in orbit around Earth, marking the beginning of space exploration.

Wiktionary

1. n. The period from the about the time of the launch of Sputnik in 1957 to the present day, during which man ventured into space.
2. n. attributive Redolent of the space age; appearing futuristic or modern.

GNU Webster's 1913

1. 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.

WordNet 3.0

1. n. the age beginning with the first space travel; from 1957 to the present