The Venera Probes
The first Soviet attempt at a flyby probe to Venus was launched on 4 February 1961, but failed to leave Earth orbit. In keeping with the (then) Soviet policy of not announcing details on failed missions, the launch was announced under the name Tyazhely Sputnik ("Heavy Satellite"). It is also known as Venera 1VA.
Venera 1 and Venera 2 were intended as fly-by probes to fly past Venus without entering orbit. Venera 1 was launched on February 12, 1961. Telemetry on the probe failed seven days after launch. It is believed to have passed within 100,000 km of Venus and entered heliocentric orbit. Venera 2 launched on November 12, 1965, but also suffered a telemetry failure after leaving Earth orbit.
Several other failed attempts at Venus flyby probes were launched by the Soviet Union in the early 1960s, but were not announced as planetary missions at the time, and hence did not officially receive the "Venera" designation.
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