Premature engine cutoff caused this early Soviet Moon mission to fall back to Earth.


This spacecraft was launched to return more detailed photos of the lunar far side, after the spectacular success of Luna 3.

The Ye-3 class vehicle was essentially a Ye-2A probe with a modified radio telemetry system, but with the original imaging system. (A more advanced Ye-3 type with a new imaging system had been abandoned earlier).

During the launch, the probe received insufficient velocity -- too low by 361 feet (110 meters) per second -- after premature third stage engine cutoff (3 seconds short). The spacecraft reached an altitude of 124,000 miles (200,000 kilometers) and then fell back to Earth and burned up in Earth’s atmosphere, much like some of the early American Pioneer probes. The most likely reentry point was over central Africa.


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

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