"artificial satellite," extended from the name of the one launched by the Soviet Union Oct. 4, 1957, from Russian sputnik "satellite," literally "traveling companion" (in this use short for sputnik zemlyi, "traveling companion of the Earth") from Old Church Slavonic supotiniku, from Russian so-, s- "with, together" + put' "path, way," from Old Church Slavonic poti, from PIE *pent- "to tread, go" (see find (v.)) + agent suffix -nik.
The electrifying impact of the launch on the West can be gauged by the number of new formations in -nik around this time (the suffix had been present in a Yiddish context for at least a decade before); Laika, the stray dog launched aboard Sputnik 2 (Nov. 2, 1957), which was dubbed muttnik in the Detroit Free Press, etc. The rival U.S. satellite which failed to reach orbit in 1957 (because the Vanguard rocket blew up on the launch pad) derided as a kaputnik (in the Daytona Beach Morning Journal), a dudnik (Christian Science Monitor), a flopnik (Youngstown Vindicator, New York Times), a pffftnik (National Review), and a stayputnik (Vancouver Sun).