1960-12-01 USSR Korabl-Sputnik 3 (Pchyolka & Mushka)

A cover commemorating the launch of Pchyolka and Mushka spaceflight, postmarked in Minsk with a hand cancel on December 1, 1960.

Korabl-Sputnik 3 (or Sputnik 6) was launched on December 1, 1960, as a test flight for the Vostok spacecraft, carrying two dogs named Pcholka and Mushka ("little bee" and "little fly"), along with a television camera and scientific instruments. The flight was considered successful from the standpoint of its orbital and biomedical testing until the attempted return to Earth.

The critical problem occurred during the December 2 deorbit maneuver. The retrorocket burn began at approximately 07:15 UTC, but the engine failed to shut down at the expected time and continued burning until its propellant was exhausted. This produced an incorrect reentry trajectory.

Because the spacecraft was no longer on a trajectory that would bring it safely back into Soviet territory, there was a risk that the capsule could land outside the USSR and potentially be recovered by another country. A self-destruct charge was therefore activated during reentry, destroying the spacecraft and killing Pchyolka and Mushka.