The Nauka were scientific subsatellites carried aboard Zenit reconnaissance satellites. From the outset, Zenits carried small supplemental science packages – for example, for making measurements of meteoroids or cosmic rays. But the first Nauka ("science") autonomous subsatellite was flown in 1968 aboard Zenit number 80. The Nauka containers served a dual purpose. Mounted on the forward end of the Zenit's reentry sphere, they provided ballast during the primary spacecraft's mission. When the Zenit had completed its work, the Nauka would be released.
Over 40 Nauka's were installed on Zenit-2 and Zenit-2M satellites from 1968 to 1979 and used to study Earth's radiation belts, collect data on the Earth-space interface, and develop test new instruments. Twenty-three autonomous Nauka subsatellites undertook research in geophysics, meteorology, and cosmic rays; others tested new systems for the Yantar reconnaissance satellite.