The USSR launched two more Sputniks, one in 1957 and one in 1958.
Sputnik 2 carried a dog, named Laika, into orbit. She was the first living creature to travel in space.
Laika did not seem to suffer from the launch, or from the weightlessness in orbit.
The USSR, however, had not created a method of bringing her safely back to Earth.
A week after the launch, Laika died due to lack of air.
About 5 months later, Sputnik 2 returned to Earth, and Laika was immortalized in history.
Sputnik 3 orbited for 691 days, studying micrometeorites, electromagnetic waves, and the Van Allen belts, or radiation zones around Earth.