On this day in space! Sept. 15, 1968: Russian tortoises (& other critters) launch around the moon on Zond 5 spacecraft in wild first circumlunar flight

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, 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.

Photos: Pioneering Animals in Space The Soviet Zond 5 rentry capsule in the ocean (left), Soviet scientists measure Zond 5 tortoises after their circumlunar flight in September 1968. (Image credit: RSC Energia) 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.

At left: The Soviet Union's Zond 5 mission launches on the first circumlunar flight on Sept.

15, 1968 from Baikonur, Cosmodrome.

At right: A view of the Earth from deep space from Zond 5. (Image credit: RSC Energia) Why it mattered In September of 1968, the Space Race to the moon was in full swing.

NASA was just three months away from the historic Apollo 8 mission, which sent the first astronauts around the moon in daring first-of-its-kind mission.

But with Zond 5, the Soviet Union scored an early win for the first circumlunar flight that launched from the Earth to the moon, then returned for a landing (or splashdown, in this case).

In fact, the flight may have spurred NASA to launch Apollo 8.