In 1969, six months before the Apollo Moon landing, and a year and a half after the last Russian and American attempts to robotically explore the planet Venus, Venera 6 was launched. It was the last of the Venus atmosphere probes launched by the Soviet Union, except for the balloons launched by the Vega mission. After Venera 6, the USSR would concentrate their planetary efforts on the herculean task of surviving landing on the hellish surface of Venus.
Venera 6 reach Venus on May 17, 1969, and survived approximately 51 minutes before succumbing most likely to the pressure. Previous attempts had exhausted their batteries before sinking deep enough to be crushed in Venus’ extraordinarily thick atmosphere, so Veneras 5 & 6 (in those days, the USSR always built probes in pairs, in case of mishap) were equipped with much smaller parachutes. This allowed them to fall to their full crush depth before running out of battery life, enabling measurements as deep as possible within the Venusian atmosphere.
It was a feet that would not be surpassed until late in 1970, when Venera 7 survived long enough to transmit some data from the surface of Venus.