Mission Type: Impact
Launch Vehicle: 8K72 (no. B1-5)
Launch Site: NIIP-5 / launch site 1
Spacecraft Mass: c. 360 kg (with upper stage)
Spacecraft Instruments: 1) three-component magnetometer; 2) two gas-discharge counters; 3) piezoelectric detector; 4) scintillation counter and 5) ion traps
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi
This mission was the third failure in a row in Soviet attempts to send a Ye-1 lunar impact probe to the Moon.
The thrust level of the core engine of the R-7 booster dropped abruptly at T+245 seconds, leading eventually to premature engine cutoff. The payload never reached escape velocity.
Later investigation showed that a pressurized seal cooling in the hydrogen peroxide pump of the main engine had lost integrity in vacuum conditions. The malfunction caused the main turbine to cease working and thus led to engine failure.