Space.com:

Fifty years ago this week, Sputnik Chief Designer Sergei Korolyov watched as a modified Russian missile launched into space from Kazakhstan’s lonely steppes carrying a very special payload.
Sputnik 1 (“traveling companion” in Russian) was about the size of a basketball and weighed about 180 pounds. It was equipped with two radio transmitters and four long antennas that broadcasted a constant beep while circling the Earth for 21 days.