Venera 8 was a probe in the Soviet Venera program for the exploration of Venus and was the second robotic space probe to conduct a successful landing on the surface of Venus. Venera 8 was a Venus atmospheric probe and lander. Its instrumentation included temperature, pressure, and light sensors as well as an altimeter, gamma ray spectrometer, gas analyzer, and radio transmitters. The spacecraft took 117 days to reach Venus with one mid-course correction on 6 April 1972, separating from the bus (which contained a cosmic ray detector, solar wind detector, and ultraviolet spectrometer) and entering the atmosphere on 22 July 1972 at 08:37 UT.

Wikipedia: https://en.wikipedia.org/wiki/Venera_8. Related NASA reference: https://nssdc.gsfc.nasa.gov/planetary/chronology.html#1972. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).