The Soviet Union's Sputnik 5 spacecraft landed safely after a full day in orbit, carrying dogs Belka and Strelka along with mice, rats, and plants, all of whom survived the mission unharmed. It was the first spaceflight to send living creatures into orbit and return them alive, a crucial proof-of-concept for the human spaceflight that would follow within a year.
Soviet space medicine had already sent dogs on suborbital hops and, famously, Laika to her death aboard Sputnik 2 in 1957 on a mission never designed for recovery. Sputnik 5, launched August 19, 1960, was different: engineers built in a functioning re-entry and recovery system specifically to prove cosmonauts could survive the trip home.
Belka and Strelka orbited Earth eighteen times over about 25 hours before their capsule parachuted safely back to Soviet soil. Strelka later gave birth to puppies, one of which, named Pushinka, was gifted by Khrushchev to President Kennedy's daughter Caroline, an unlikely piece of Cold War diplomacy conducted entirely through dog breeding. Within eight months of the successful flight, Yuri Gagarin became the first human in space, riding the confidence this mission had helped establish.
Key people: Belka, Strelka