Venera 11

Venera 11 was a Soviet uncrewed space mission, part of the Venera program, launched on September 9, 1978. Its primary objective was to conduct further studies of Venus, including its atmosphere, surface, and cloud layers. The mission consisted of a flyby spacecraft and a lander.

The flyby bus acted as a communications relay for the lander. It also carried instruments for studying the solar wind and interplanetary magnetic field during its journey to Venus.

The lander separated from the flyby spacecraft shortly before entering the Venusian atmosphere on December 25, 1978. It deployed a parachute system to slow its descent and began transmitting data as it descended through the atmosphere.

Venera 11 transmitted data from the surface for approximately 95 minutes before succumbing to the extreme temperatures and pressures of the Venusian environment.

The lander carried a suite of instruments, including gas chromatographs, spectrometers, and nephelometers, to analyze the composition of the Venusian atmosphere and clouds. It also included a drill to sample the surface material.

While Venera 11 did not return images from the surface (due to camera lens cap failure), it provided valuable data about the Venusian atmosphere, including measurements of lightning activity and the presence of carbon monoxide at lower altitudes. It also confirmed the presence of a high concentration of chlorine in the clouds. This information contributed significantly to our understanding of Venus's harsh environment and the processes shaping its atmosphere.