Goals: This mission, like its twin Venera 12, called for a flyby
spacecraft and a lander to explore Venus' ionosphere, atmosphere
and surface and the interplanetary environment. Accomplishments:
The flyby craft studied the solar wind, gamma-ray bursts,
ultraviolet radiation, and Venus' ionosphere. It passed the
planet at a distance of about 35,000 km (about 22,000 miles).
The lander probed Venus' atmosphere as it descended and then
transmitted data from the surface for 95 minutes. Its camera
system and soil-analysis experiment failed, but the mission did
report evidence of lightning and thunder, carbon monoxide at low
altitudes, and data on isotopes of argon that prompted
scientists to question the theory that the original atmospheres
of Venus, Earth and Mars were the result of outgassing from
volcanoes.