Sputnik 20 (1962 Alpha Tau 1) 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 on 1 September 1962. Ignition of the Block L engine to achieve Venus orbit failed when a fuel valve did not open and the spacecraft was stranded in Earth orbit until it re-entered the Earth's atmosphere 5 days later. Spacecraft and Subsystems Sputnik 20 was a Venera-type (2MV-1) lander with power supplied by 2.6 square meters of solar panels powering a 42 amp/hr cadmium-nickel battery. Thermal control was achieved by epoxy-resin heat shields and an ammonia-based cooling system. Sun-Earth sensors were used for spacecraft pointing. Communications were via a 1 m wavelength omni-directional antenna, a 1.7 high-gain antenna at 5 cm, 8 cm, and 32 cm wavelengths, and a small antennae on the solar panels at 1.6 m wavelength. The spacecraft scientific payload comprised ultraviolet detectors, a chemical gas analyzer, temperature, density, and pressure sensors, a gamma-ray counter, movement detector, a surface gamma-ray detector, and a meteorite detector. This spacecraft was originally designated Sputnik 24 in the U.S. Naval Space Command Satellite Situation Summary. Spacecraft image for illustrative purposes - not necessarily in the public domain.