Zond 6 was part of the Soviet Union's crash effort to send cosmonauts around the Moon before the United States, following a lunar trajectory and returning stunning photographs of the lunar surface and Earth. A cabin depressurization during the return and a parachute failure on landing destroyed the capsule, though its film canister survived, giving Soviet engineers false confidence about crewed lunar flight just before Apollo 8's success.
By late 1968, the Soviet Union was racing desperately to send a cosmonaut around the Moon before NASA could, hoping at least to claim a symbolic victory in the increasingly lost Space Race. Zond 6, launched atop a Proton rocket, was an uncrewed test of the Soyuz-based circumlunar spacecraft meant eventually to carry a human crew on a similar loop trajectory without entering lunar orbit.
The mission looped around the far side of the Moon, capturing photographs later celebrated for their beauty, including striking images of Earth rising over the lunar horizon. But the return leg proved catastrophic: a seal failure caused the cabin to lose pressure during the return flight, which would have killed any cosmonauts aboard, and then the parachute system fired too early during reentry, causing the capsule to crash into the Kazakh steppe at high speed.
Soviet engineers recovered the film, undamaged despite the crash, and briefly considered declaring the mission enough of a success to attempt a crewed circumlunar flight before Apollo 8. Chief designer Vasily Mishin's team ultimately judged the spacecraft too unreliable to risk cosmonaut lives. Weeks later, Apollo 8 became the first crewed mission to orbit the Moon, ending Soviet hopes of winning that leg of the race.
Key people: Vasily Mishin