Venera 1, also known as Venera-1VA No.2 and occasionally in the West as Sputnik 8, was the first spacecraft to perform an interplanetary flight and the first to fly past Venus, as part of the Soviet Union's Venera programme. Launched in February 1961, it was intended as an impactor, but flew past Venus on 19 May of the same year; however, radio contact with the probe was lost before the flyby, resulting in returning only some data and only from interplanetary space. Venera 1 was a 643.5-kilogram (1,419 lb) probe consisting of a cylindrical body 1.05 metres (3 ft 5 in) in diameter topped by a dome, totalling 2.035 metres (6 ft 8.1 in) in height.

Wikipedia: https://en.wikipedia.org/wiki/Venera_1. Related NASA reference: https://nssdc.gsfc.nasa.gov/planetary/chronology.html#1961. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).