The brief and disasterous flight of Laika
History has long recorded Laika the dog, the first living being in space, as having survived for some time after her lauch by the USSR in November 1957. Because Sputnik 2 couldn't be returned to Earth safely, the offical line was that Laika was given a dose of poisoned rations after a week in space, and died peacefully, saving her from a death-from-re-entry. A later therory emerged claiming she only lived 4 days, then overheated. The reciently revealed truth is even worse, and shows that the little stray died a much nastier death than the poison story, and much sooner than four days. Within the first few hours after launch, Laika was dead from overheating and panic.
Ironically, her 'sucess' was taken to show that people wouldn't come to harm from the forces and stresses of a launch and a zero-g environment, leading to the first people in space.