mission of venera
The Venera (Cyrillic: ÐÐµÐ½ÐµÑÐ°) series of probes were developed by the USSR between 1961 and 1984 to gather data from Venus. As with some of the USSR's other planetary probes, the later versions were launched in pairs with a second vehicle being launched soon after the first of the pair.
Ten probes from the Venera series successfully landed on Venus and transmitted data from the surface, including the two Vega program and Venera-Halley probes. In addition, thirteen Venera probes successfully transmitted data from the atmosphere of Venus.
Among the other results, probes of the series became the first man-made devices to enter the atmosphere of another planet (Venera 4 on October 18, 1967), to make a soft landing on another planet (Venera 7 on December 15, 1970), to return images from the planetary surface (Venera 9 on June 8, 1975), and to perform high-resolution radar mapping studies of Venus (Venera 15 on June 2, 1983). So, the entire series could be considered as highly successful. Unfortunately the surface conditions on Venus are extreme, which meant that the probes only survived on the surface for a duration of 23 minutes (initial probes) up to about two hours (final probes).
Venera is the Russian name for Venus.