Soviet Union Venera program: Venera 7 launched. It will become the first spacecraft to successfully transmit data from the surface of another planet (Venus).

The Venera program was a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus.

Venera 7 was a Soviet spacecraft, part of the Venera series of probes to Venus. When it landed on the Venusian surface on 15 December 1970, it became the first spacecraft to soft land on another planet and the first to transmit data from there back to Earth.

Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" among the planets of the Solar System for its orbit being the closest to Earth's, both being rocky planets and having the most similar and nearly equal size and mass. Venus, though, differs significantly by having no liquid water, and its atmosphere is far thicker and denser than that of any other rocky body in the Solar System. It is composed of mostly carbon dioxide and has a cloud layer of sulfuric acid that spans the whole planet. At the mean surface level, the atmosphere reaches a temperature of 737 K and a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a supercritical fluid. From Earth Venus is visible as a star-like point of light, appearing brighter than any other natural point of light in Earth's sky, and as an inferior planet always relatively close to the Sun, either as the brightest "morning star" or "evening star".