Venera 7, Soviet probe to Venus, launched 1970

Venera 7, a Soviet spacecraft and lander to Venus, was launched August 17, 1970.  The probe entered the Venusian atmosphere December 15 and the lander broke away from the bus.  The lander's parachute opened at an altitude of 60km and began the probe began to take tests, revealing the Venusian atmosphere to be 97% carbon dioxide.

The probe seemed to go silent upon impact, due to the parachute somehow failing during descent, but recording tapes kept going.  A few weeks later, scientists discovered about 23 minutes of weak signals.  They concluded the spacecraft had landed safely but harder than expected.  It bounced onto its side and the main antenna was pointed in the wrong direction to send strong signals to Earth.

Venera 8 lands on Venus, 1972

The Soviet probe Venera 8 touched down on Venus July 22, 1972, becoming the second spacecraft to land on the planet, but it was the first one to make a soft landing. It was preceded by Venera 7 in December 1970, whose parachutes failed to deploy and it hit the surface at about 16.5m/sec.

Venera 8 transmitted for just over 50 minutes before going silent.  It confirmed data from Venera 7 about the harsh conditions on Venus.

Venera 8, Venus lander, launched 1972

Venera 8, the Soviet lander, was launched March 27, 1972 and made a successful landing on Venus July 22.  It transmitted during its descent and continued to transmit for just over 50 minutes after landing.  It confirmed the high temperatures and high pressures discovered by Venera 7 about a year and a half earlier.

Venera 8 showed that the Venusian clouds end at a high altitude and the atmosphere is mostly clear at ground level.