The objectives of the mission included the study of: 137 radio transmissions and 277 orbits of the Moon were completed before the batteries failed on 1 October 1966.

A secondary objective was to obtain data on mass concentrations ("mascons") on the Moon first detected by Luna 10.

Using the Ye-6 bus, a suite of scientific instruments (plus an imaging system similar to the one used on Zond 3) replaced the small lander capsule used on the soft-landing flights.

To reduce problems caused by damage to the film due to solar radiation it was planned to take all photos within the first 24 hours of lunar orbits.

During the mission, the TV camera failed to return usable images because the spacecraft lost proper orientation to face the lunar surface when a foreign object was lodged in the nozzle of one of the attitude-control thrusters.