On February 12, 1961 at 00:34 UTC the first planetary probe was launched to Venus by the Soviet Union.
The "Venera–1” (Venus-1) Automatic Interplanetary Station was a 643.5 kg probe consisting of a cylindrical body 1.05 meter in diameter topped by a dome, totaling 2.035 meters in height. Two solar panels extended from the cylinder, charging a bank of silver-zinc batteries.
Three successful telemetry sessions were conducted, gathering solar-wind and cosmic-ray data near Earth, at the Earth's magnetopause, and on February 19 at a distance of 1900000 km.
On May 19 and 20, 1961, Venera 1 passed within 100000 km of Venus and entered a heliocentric orbit. Although it failed to function before reaching Venus, Venera-1 was an important milestone in spacecraft design—the first truly modern planetary probe.