Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. First Zenit-2M launch - optical system improved over Zenit-2. Carried the first Nauka autonomous module - it conducted high energy gamma ray experiments as well as observing protons with energies above 100 MeV and electrons with energies above 20 MeV.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that conducted cosmic ray experiments and high energy gamma ray experiments as well as observing protons with energies above 100 MeV and electrons with energies above 20 MeV.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after eleven days. Carried Nauka autonomous module that contained infrared and microwave telescope to study radiation from the Earth - in particular, it looked at ice in the polar regions.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module.

Imaging satellite equipped with film cameras for photo-reconnaissance - recovered after eight days. It seems to have been an exception in that it was the only Zenit-2 (the remainder were Zenit-2M) to carry a Nauka module - equipment probably related to development of spacecraft systems. Landed 150 km NW of Tselinograd - 53°23' north, 70°09' east.

Prototype biological research satellite, based on the Zenit-2M film imaging satellite with the experiments payload replacing the cameras. Experiments included a developmental version of the "Oasis" bacteriological cultivation system. Launch announcement referred to "...trying out experimental life-sustaining systems for test animals and for further studying the effect of space flight on living organisms". No actual animals were carried and the living organisms were seeds, plants, frogs' eggs, yeast and other cells. Also carried Nauka autonomous module equipped with spectrometers to measure fluxes of high-energy protons and electrons "to continue research into the physical properties of outer space". Recovered after six days rather than the usual 12 days of a Zenit-2M.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that contained infrared and microwave telescope to study radiation from the Earth.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module with radiation monitoring equipment.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that made electron and gamma ray measurements as well using a scintillation spectrometer sensitive to X-rays in the energy range >30 keV, with a 2 deg x 17 deg field of view. In addition, there was an X-ray telescope which operated in the range 2-30 keV. The package detected several X-ray sources which were correlated to already identified Uhuru (another X-ray satellite) point sources and discovered new sources in the direction of the constellation Cetus.

Second generation imaging satellite equipped with film cameras for photo-reconnaissance and an orbit adjustment motor - failed to reach orbit.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module with equipment for radiation studies.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - failed to reach orbit. Carried Nauka autonomous module for electric field studies.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that studied particle flux and radiation.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that conducted cosmic ray experiments and measured solar radiation.

High-energy physics research satellite based on the Zenit imaging satellite with the science payload replacing the cameras. The main instrument on board was an ionization calorimeter assembled by the Soviet Union with some of components supplied by Hungary, Poland, Mongolia, Czechoslavakia, and Roumania. Also included was a multilayered silver bromide photographic emulsion stack designed to detect and track high-energy primary cosmic rays, as well as electronic equipment to detect, identify and measure the same radiation. A meteorite detector was also carried built with components from the USSR, Czecholslovakia and the Hungary. Total Mass of internal scientific instrumentation - 1200 kg, including 1070 kg for the high-energy particle detectors. Part of the payload was carried in an autonomous 'Nauka' module. Intercosmos 6 built on the work undertaken by the 'Proton' satellites, 1965-1968. Returned to Earth after four days - the mission duration was chosen to avoid the detector emulsions becoming saturated.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that measured electron flux, cosmic rays and gamma ray bursts.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that tested components of the Condor control unit for the upcoming Yantar series - it was separated about day 9 of the flight.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that tested components of the Condor control unit for the upcoming Yantar series - it was separated about day 4 of the flight.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module equipped with Cerenkov-scintillation telescopes to study electron fluxes with energies greater than 10 MeV and protons with energies from 400 MeV to 1.2 GeV.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module equipped with a gamma-ray telescope with an accoustic spark chamber to search for local gamma-quanta sources with energies above 100 MeV.

Biological research satellite, based on the Zenit film imaging satellite (probably the 2M version) with the experiments payload replacing the cameras. Carried Nauka autonomous module The re-entry cabin was recovered.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module that tested navigation equipment and radio-altimeter for Yantar - it separated about day 4 of the flight.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module studying infrared radiation from the Earth and from the space background. The instrument was a 100mm diameter Cassegranian telephoto lens, with two helium-cooled detectors.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module studying cosmic rays. Made simultaneous observations with Intercosmos 13.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module equipped with a gamma-ray telescope with an accoustic spark chamber to search for local gamma-quanta sources with energies above 100 MeV.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module with test equipment that might have been related to development of plasma thrusters for spacecraft.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module with X-ray spectrometers covering the 20-320 keV range, and gamma-ray spectrometers sensitive to 100-4000 MeV to observe high-energy diffuse gamma-radiation. X-ray studies were conducted of the Cygnus X-1 and Cygnus X-2 sources in particular. Unexpectedly, no X-ray bursts were detected during the course of the mission.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module with X-ray spectrometers covering the 20-320 keV range, and gamma-ray spectrometers sensitive to 100-4000 MeV to observe high-energy diffuse gamma-radiation.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 12 days. Carried Nauka autonomous module but Kettering group telemetry analysis did not indicate its presence.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module.

High-energy physics research satellite based on the Zenit imaging satellite with the science payload replacing the cameras. Investigating primary cosmic radiation and meteoritic particles in near-earth outer space using equipment similar to that aboard Intercosmos 6 (1972-27A/5936). Part of the payload was carried in an autonomous 'Nauka' module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after 13 days. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - recovered after nine days, a shorter mission than normal. Carried Nauka autonomous module.

Second Generation imaging satellite equipped with film cameras for photo-reconnaissance - failed to reach orbit. Carried Nauka autonomous module.

Imaging satellite equipped with multi-spectral film cameras for remote sensing under the Priroda project. The launch announcement mentioned "...investigation of natural resources .... in the interests of the economy and international cooperation". Carried Nauka autonomous module.

Imaging satellite equipped with multi-spectral film cameras for remote sensing under the Priroda project. The launch announcement mentioned "...investigation of natural resources .... in the interests of the economy and international cooperation". Carried Nauka autonomous module that included two identical combined scintillation spectrometers for the detection of hard X-rays and gamma rays.

Imaging satellite equipped with multi-spectral film cameras for remote sensing under the Priroda project. The launch announcement mentioned "...investigation of natural resources .... in the interests of the economy and international cooperation". Carried Nauka autonomous module. This was the final launch of a Zenit-2M.

Science satellite based on the Bion derivative of the Zenit spacecraft and studying the energy spectrum and charge composition of primary cosmic rays with energy above 2 TeV. The main instrument was the 'Sokol', consisting of an ionization calorimeter and two Cerenkov detectors which was used to investigate primary cosmic rays at energies of 1-10 TeV. Total mass of scientific equipment - 2450 kg. Part of the payload was carried in an autonomous 'Nauka' module. Functioned until 1984 Apr 5 when the satellite executed a destructive re-entry - the cabin had no heat shielding. Efir in English is 'Ether'.

Science satellite based on the Bion derivative of the Zenit spacecraft and studying the energy spectrum and charge composition of primary cosmic rays with energy above 2 TeV. The main instrument was the 'Sokol-2', consisting of an ionization calorimeter and Cerenkov detectors, which was used to investigate primary cosmic rays at energies of 1-10 TeV. Total mass of scientific equipment - 2450 kg. Part of the payload was carried in an autonomous 'Nauka' module. Functioned until 1986 Jan 22 when the satellite executed a destructive re-entry - the cabin had no heat shielding. Efir in English is 'Ether'.