Venera 4 was launched towards Venus
On June 12, 1967, the Soviet Union launched Venera 4, an atmospheric probe of Venus.
The probe arrived at Venus on October 18, 1967, and was the first probe to go directly into the atmosphere and return atmospheric data.
Venera 4's landing on Venus lasted 93 minutes, and after deploying a parachute at an altitude of 52 km, the capsule began sending back data on atmospheric pressure, temperature, and gas composition. The probe's temperature control equipment kept the temperature inside the capsule at minus 8 degrees Celsius.
The chemical composition of the atmosphere was measured as 90-93% carbon dioxide, 0.4-0.8% oxygen, 7% nitrogen and 0.1-1.6% water vapor.
Venera 4 did not detect any radiation belts. Venus' measured magnetic field was 3,000 times weaker than Earth's, and the hydrogen corona was 1,000 times less dense.
All the data indicated that if there was water, it was lost long ago. This conclusion was unexpected considering the dense clouds of Venus.
The probe also provided the first proof that Venus is very hot with its measurements.
Before Venus 4 reached the surface, it was crushed by Venus's atmospheric pressure. But the mission was considered a complete success, especially considering several previous Venera programs had all failed.
