It becomes the second probe to enter the atmosphere of Venus and the first to send back data about it.
The main mission of Venera 4 was the direct study of the Venusian atmosphere. It was part of the Soviet Venera programme. It was equipped with two thermometers, a barometer, a radio altimeter, a gas analyser and two radio transmitters. Venera 4 was the first probe to successfully analyse the atmospheric environment of another planet. It was also the first probe to land gently on another planet, following the earlier impact on the surface of Venera 3.
Capsule of Venera-4 in Memorial Museum of Astronautics