Lunar Orbiter. The objectives of the spacecraft included the study of: (1) lunar gamma- and X-ray emissions in order to determine the Moon's chemical composition; (2) lunar gravitational anomalies; (3) the concentration of meteorite streams near the Moon; (4) the intensity of hard corpuscular radiation near the Moon. The spacecraft could also be equipped with a television system that obtained and transmitted photographs of the lunar surface. The photographs contained 1100 scan lines with a maximum resolution of 14.9--19.8 m.

Soft landed on moon; returned soil density data, photos. Modernised version of the E-6 with the ALS lander mass increased from 84 kg to 150 kg. Conducted further scientific investigation of the moon and circumlunar space. As with the E-6, after impact on the lunar surface by landing bag, the petal encasement of the spacecraft was opened, antennas were erected, and radio transmissions to Earth began four minutes after the landing. The additional payload meant that in addition to the camera the spacecraft was equipped with a mechanical soil-measuring penetrometer, a dynamograph, and a radiation densitometer for obtaining data on the mechanical and physical properties and the cosmic-ray reflectivity of the lunar surface.

Development of system to permit the creation of an artificial lunar satellite for the investigation of circumlunar space; development of onboard systems for putting a station into a selenocentric (circumlunar) orbit. Scientific instruments included a gamma-ray spectrometer for energies between 0.3--3 MeV, a triaxial magnetometer, a meteorite detector, instruments for solar-plasma studies, and devices for measuring infrared emissions from the Moon and radiation conditions of the lunar environment. Gravitational studies were also conducted. The spacecraft played back to Earth the `Internationale' during the Twenty-third Congress of the Communist Party of the Soviet Union. Battery powered and operated for 460 lunar orbits and 219 active data transmissions before radio signals were discontinued.

The E-6LS was a radio-equipped version of the E-6 used to test tracking and communications networks for the Soviet manned lunar program. Otherwise the spacecraft instrumentation was similar to that of the E-6LF and provided data for studies of the interaction of the earth and lunar masses, the lunar gravitational field, the propagation and stability of radio communications to the spacecraft at different orbital positions, solar charged particles and cosmic rays, and the motion of the Moon.