Sputnik 3 (Russian: Спутник-3, Satellite 3) was a Soviet satellite launched on May 15, 1958 from Baikonur cosmodrome by a modified 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 counterpart, Vanguard 1, Sputnik 3 had succeeded in making it into orbit during the IGY.