Mission Type: Lander
Launch Vehicle: SS-6 (Sapwood) with 2nd Generation Upper Stage + Escape Stage, 8K78 (no. U103-28)
Launch Site: Tyuratam (Baikonur Cosmodrome), USSR, NIIP-5 / launch site 3
Spacecraft Mass: 1,552 kg
Spacecraft Instruments: 1) imaging system and 2) radiation detector
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

This Soviet attempt to achieve a lunar soft-landing nearly succeeded. After a successful midcourse correction on 4 December, the spacecraft headed toward the Moon without any apparent problems.

Just prior to the planned retro-fire burn, a command was sent to inflate cushioning airbags around the ALS lander probe. Unfortunately, a plastic mounting bracket apparently pierced one of the two bags. The resulting expulsion of air put the spacecraft into a spin of 12 degrees per second. The vehicle momentarily regained attitude, long enough for a 9-second retro-engine firing, but then lost it again.

Without a full retro-fire burn to reduce approach velocity sufficient for a survivable landing, Luna 8 plummeted to the lunar surface and crashed at 21:51:30 UT on 6 December just west of the Kepler crater. Impact coordinates were 9°8' north latitude and 63°18' west longitude.