Mission Type: Flyby
Launch Vehicle: 8K78 (no. T15000-19)
Launch Site: NIIP-5 / launch site 1
Spacecraft Mass: c. 800 kg
Spacecraft Instruments: ) radiation detector; 2) charged-particle detector; 3) magnetometer; 4) piezoelectric detector; 5) atomic hydrogen detector; 6) radio telescope; 7) ultraviolet and Roentgen solar radiation experiment; 8) technology experiment and 9) plasma engines
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

This was another Soviet "third generation" deep space probe that failed to accomplish its mission of a Venus flyby.

This spacecraft failed to reach Earth orbit due to a malfunction in the launch vehicle's third stage. Later investigation indicated that a liquid oxygen leak through an unpressurized valve seal froze propellant in the main pipeline. As a result, the pipeline cracked, leading to an explosion in the third stage.