15-MAY-1958:- The Soviet Union launches Sputnik 3.

Sputnik 3 

Was a Soviet satellite launched on May 15, 1958 from Baikonur cosmodrome by amodified R-7/SS-6 ICBM. It was a research satellite to explore the upper atmosphere and the near space and carried a large array of instruments for geophysical research.

Sputnik 3 was the only Soviet satellite launched in 1958. Like its American counter part, Vanguard 1, Sputnik 3 had succeeded in making it into orbit during the IGY.