Venera 4

The Soviet Union launches Venera 4, a space probe dispatched to the planet Venus. Venera 4 is equipped with a landing probe which it deposits into the planet’s dense atmosphere in October, and the probe’s findings stun scientists on Earth who had long considered Venus a near-twin of Earth: the atmosphere is predominantly carbon dioxide, with minimal oxygen and a pressure nearly 100 times Earth’s atmospheric pressure at sea level. The temperature within the Venusian atmosphere is found to soar past 800 degrees Fahrenheit, presenting a challenge for designers of the next round of vehicles to visit the planet. The Venera 4 landing probe is not equipped with cameras, and contact is lost with it before contact is made with the ground.