Laika (from Russian: Лайка, "Barker", as well as a name of a dog breed) was a Russian space dog that became the first living creature from Earth to enter orbit. She was found as a stray wandering the streets of Moscow. Originally named Kudryavka, she was renamed Laika after her breed type. After undergoing training with two other dogs, she was selected to be the occupant of the Soviet spacecraft Sputnik 2 and was launched into space on November 3, 1957.
Laika died a few hours after launch from stress and overheating, likely due to a malfunction in the thermal control system. The true cause of her death was not made public until decades after the flight. Some former Soviet scientists have since expressed regret that Laika was allowed to die.
Although Laika did not survive the trip, the experiment proved that a living passenger could survive being launched into orbit and endure weightlessness. It paved the way for human spaceflight and provided scientists with some of the first data on how living organisms react to spaceflight environments.