Goals: Like Venera 4 and 5, Venera 6 was to analyze the atmosphere of Venus while descending through it. The launchings of twin spacecraft Venera 5 and 6 were timed so they would arrive at Venus one day apart, allowing for some cross-calibration of data. The parachutes on the atmospheric probes were 2/3 as large as those used for Venera 4 to allow a faster descent. It was hoped that this would enable them to reach lower altitudes before being crushed or having their electronics disabled by heat.
Accomplishments: The strategy did not work. Venera 6 transmitted data for only 51 minutes as it fell, about 2 minutes less than Venera 5. Just before the probe was presumably crushed, its instruments indicated an atmospheric pressure of 26 Earth atmospheres and an altitude of 10 to 12 km. This was nearly the same pressure that Venera 5 measured at a much higher altitude, so it has been suggested that Venera 6 landed on a mountain or high plateau, or that the instruments suffered damage during descent, causing the radio altimeter to give a false reading.