Belka (literally, "Squirrel" or alternatively "Whitey") and Strelka ("Little Arrow") spent a day in space aboard Korabl-Sputnik 2 (Sputnik 5) on 19 August 1960 before safely returning to Earth.

They were accompanied by a grey rabbit, 42 mice, two rats, flies and several plants and fungi. All passengers survived. They were the first Earth-born creatures to go into orbit and return alive.

Strelka went on to have six puppies with a male dog named Pushok who participated in many ground-based space experiments, but never made it into space.

One of the pups was named Pushinka ("Fluffy") and was presented to President John F. Kennedy by Nikita Khrushchev in 1961. A Cold War romance bloomed between Pushinka and a Kennedy dog named Charlie, resulting in the birth of four pups that JFK referred to jokingly as pupniks.

More Info: en.wikipedia.org