Date: 1 Sep 1962
Sputnik 20 (Unnamed Venera 2MV-1/2) was intended to be a Venus landing mission. The Venera-type spacecraft was successfully inserted into geocentric orbit by the SL-6/A-2-e launcher. The escape stage failed and the spacecraft was stranded in Earth orbit until it re-entered the Earth's atmosphere 5 days later.
This spacecraft was originally designated Sputnik 24 in the U.S. Naval Space Command Satellite Situation Summary.