By some definitions, you could say that spaceflight began 50 years ago today.
On August 19, 1960, the Soviet Union launched the Sputnik 5 capsule containing 40 mice, two rats, a rabbit, some fruit flies, plants—and a pair of dogs, Belka ("Whitey") and Strelka ("Little Arrow.") They were the first living creatures to go into orbit and return safely. And they gave the Soviets confidence to send a human into space less than a year later.
You can see contemporary footage of the space dogs here, and a 2005 BBC dramatization of the Sputnik 5 launch (and a failed precursor), with a cranky Sergey Korolev overseeing the launch.
According to Chris Dubbs, author of Space Dogs: Pioneers of Space Travel, Russian space doctors were at first alarmed when TV transmissions from the Sputnik 5 capsule showed neither dog moving the slightest bit during the first three orbits.
Finally, on the fourth orbit, Belka gave a little shudder and vomited. It seemed to snap both dogs out of a trance, breaking the spell of the strange experience of being without gravity. For the rest of the flight they looked more alert.
Belka and Strelka became instant folk heroes, and in the 50 years since have inspired everything from cartoons (of the Ren & Stimpy school), to vodka to Russia's first 3-D animated film, "Belka and Strelka, Star Dogs," released this year in time for the anniversary.
Both dogs were "preserved" after their death, and are now on display at the Museum of Cosmonautics in Moscow. Strelka, though, lives on through her heirs. She had a daughter, Pushinka, who was given by Soviet Premier Nikita Khrushchev to First Lady Jacqueline Kennedy when her family lived in the White House. Among other tricks, Pushinka learned to climb the ladder to daughter Caroline's playhouse. She had four puppies of her own—Blackie, Butterfly, White Tip and Streaker—who were later given away.