Laika died hours into Sputnik 2 mission

Laika, a stray dog plucked from Moscow streets, launched aboard Sputnik 2 on 3 November 1957. Soviet engineers built the satellite in under a month for Khrushchev's deadline. The thermal control system failed because insulation tore loose, and the cabin exceeded 40°C. Laika died within hours, with no plan to return her.