On Sept. 15, 1968, the Soviet Union launched the Zond 5 spacecraft on a mission to loop around the moon and return to Earth.

There were no cosmonauts aboard Zond 5, but there were several smaller vertebrates — including the first two tortoises to ever go to space! Other passengers included wine flies, mealworms, plants and seeds. These were the first animals in deep space and the first to travel around the moon. After looping around the moon, the Zond 5 spacecraft turned around and came back to Earth. It was supposed to land in Kazakhstan on Sept. 22, but the spacecraft's guidance system failed, and it splashed down in the Indian Ocean instead. The Soviets did recover the capsule and found that the tortoises and other critters were still alive, although they had lost some weight since the start of the mission.