Mission Type: Lander, Sample Return
Launch Vehicle: 8K82K + Blok D (Proton-K no. 287-02)
Launch Site: NIIP-5 / launch site 81L
Spacecraft Mass: About 5,800 kg
Spacecraft Instruments: 1) stereo imaging system; 2) improved drill for sample collection; 3) radiation detector and 4) radio-altimeter
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 the second attempt by the Soviet Union to send an advanced lunar sample return craft to the Moon, equipped with the capability to dig for a deeper core. The first spacecraft (Luna 23) was damaged during landing on the Moon in October 1974.

On this mission, the first three stages of the Proton-K launch vehicle worked without fault, but the Blok D stage, during its first burn for insertion into Earth orbit, failed. The expensive payload burned up in Earth's atmosphere without ever reaching Earth orbit.