ব্যাখ্যা
Sputnik, any of a series of three artificial Earth satellites, the first of whose launch by the Soviet Union on October 4, 1957, inaugurated the space age.
Sputnik 1, the first artificial satellite launched, was a 83.6-kg (184-pound) capsule.
It achieved an Earth orbit with an apogee (farthest point from Earth) of 940 km (584 miles) and
a perigee (nearest point) of 230 km (143 miles), circling Earth every 96 minutes and remaining in orbit until January 4, 1958,
when it fell back and burned in Earth’s atmosphere.
The launch of Sputnik 1 shocked many Americans, who had assumed that their country was technologically ahead of the Soviet Union,
and led to the “space race” between the two countries.
Source: Britannica.