12. The first probe to perform a planetary flyby on May 19, 1961, Venera 1, unfortunately, failed to provide any scientific data from this event due to a systems failure
Launched on February 12, 1961, the flight of Venera 1, known in the West as Sputnik 8, was responsible for several historic firsts. Consisting of an almost 1,500 lbs probe, the mission objective was to reach the planet Venus for the first time. Fired into a low Earth orbit, Venera 1 utilized the world’s first staged-combustion rocket engine, as well as the first use of liquid-fuel in outer space. The upper stage subsequently propelled the spacecraft beyond the orbit of the Earth and into a heliocentric orbit heading in the direction of Venus.
En route during its journey, Venera 1 became the first spacecraft to perform mid-course corrections, in addition to spin-stabilization, both of which would become staples of spaceflight in future decades. Successfully flying past Venus on May 19, becoming the first man-made object to perform a planetary flyby, the probe had unfortunately lost radio contact with mission control on Earth. Consequently, no information was relayed and no data acquired from this milestone. It is believed that the solar sensors might have suffered critical overheating as the probe approached the Sun.