Laika died within hours from overheating, possibly caused by a failure of the central R‑7 sustainer to separate from the payload.

The experiment, which monitored Laika's vital signs, aimed to prove that a living organism could survive being launched into orbit and continue to function under conditions of weakened gravity and increased radiation, providing scientists with some of the first data on the biological effects of spaceflight. Little was known about the effects of spaceflight on living creatures at the time of Laika's mission, and animal flights were viewed by engineers as a necessary precursor to human missions. She died of overheating hours into the flight, on the craft's fourth orbit. As the technology to de-orbit had not yet been developed, Laika's survival was never expected. A stray mongrel from the streets of Moscow, she flew aboard the Sputnik 2 spacecraft, launched into low orbit on 3 November 1957.

1954 – 3 November 1957) was a Soviet space dog who was one of the first animals in space and the first to orbit the Earth.