Zond 6 was a formal member of the Soviet Zond program, and an unpiloted version of the Soyuz 7K-L1 crewed Moon-flyby spacecraft. It was launched on a lunar flyby mission on November 10, 1968, from a parent satellite (68-101B) in Earth parking orbit. The spacecraft carried a biological payload of turtles, flies, and bacteria. It also carried scientific probes including cosmic ray, micrometeoroid detectors, and photographic equipment. The mission was a precursor to a crewed circumlunar flight which the Soviets hoped could occur in December 1968, thus beating the American Apollo 8. However, after rounding the Moon on November 14, Zond 6 crashed on its return to Earth, due to a parachute failure when the parachute was detached from the capsule too early.

Wikipedia: https://en.wikipedia.org/wiki/Zond_6. Related NASA reference: https://nssdc.gsfc.nasa.gov/planetary/chronology.html#1968. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).