Here is a postage stamp "Belka and Strelka" from Soviet Union, with very famous dogs on it who did their feat of arms 49 years ago:
Belka (literally "squirrel", or but as a dog's name most likely means "Whitey" ) and Strelka ("Arrow" ) spent a day in space aboard Korabl-Sputnik-2 (Sputnik 5) on August 19, 1960 before safely returning to Earth.
They were accompanied by a grey rabbit, 42 mice, 2 rats, flies and a number of plants and fungi. All passengers survived. They were the first Earth-born creatures to go into orbit and return alive.