On this day in 1957, the Soviet Union launched Sputnik 2, the first spacecraft to carry a living animal, a dog named Laika. The three-year old mixed breed was a stray found wandering the streets of Mosow by Soviet scientists. Sputnik 2 was not designed to return to Earth. Laika became the first living creature to orbit the earth and subsequently became the first casuality of the Space Race when she died from overheating and stress a few hours into the flight.
Her true cause of death was kept a secret until after the fall of the Soviet Union. In 1998, Oleg Gazenko, one of the scientists involved with the Sputnik program, said "Work with animals is a source of suffering to all of us. We treat them like babies who cannot speak. The more time passes, the more I'm sorry about it. We shouldn't have done it. We did not learn enough from this mission to justify the death of the dog."
A memorial to Laika was unveiled in 2008. It stands near the site of the military facility where she was trained.