It was launched in on 3 December 1965 with the objective of achieving a soft landing on the Moon; however, its retrorocket firing occurred too late, and suffered a hard impact on the lunar surface on the Oceanus Procellarum (Ocean of Storms).

The mission did complete the experimental testing of its stellar-guidance system and the ground-control of its radio telemetry equipment, its flight trajectory, and its other instrumentation.

Just before the scheduled firing of its retrorocket, a command was sent to inflate cushioning air bags around the landing probe.

The spacecraft momentarily regained its proper attitude, long enough for a nine-second-long retrorocket firing, but Luna 8 became unstable again.

Without a retrorocket burn long enough to reduce its velocity sufficiently for a survivable landing, Luna 8 plummeted to the lunar surface and crashed at 21:51:30 UT on 6 December in the west of Oceanus Procellarum.