2MV-1 No. 2 (Venera)
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This was the second of three Venus spacecraft launched by the Soviets in 1962.
Like its predecessor launched in Aug. 1962 (also a Venus impact probe), the spacecraft never left parking orbit around Earth due to a malfunction in the Blok L upper stage designed to send the probe out of Earth orbit towards Venus.
The valve that controlled the delivery of fuel into the combustion chamber of the Blok L engine (the S1.5400) never opened. As a result, the engine did not fire. The payload decayed within five days of launch.
Source
Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.