In 1969, TsSKB-Progress started the development of spacecraft for studying the fundamental issue of astrophysics – the problem of cosmic rays origin and propagation. Such research is considerably difficult. The Earth’s atmosphere, obstructing the space radiation research is one of the factors influencing on accuracy of experiments. Experimentation in space essentially facilitates research in this field of science.

For such experiments, TsSKB-Progress developed two spacecraft called Energiya.

Energiya spacecraft was applied for:

· study of superhigh-energy particles (Energiya-1, Energiya-2) and solid part of the interplanetary medium (Energiya-1) within the framework of collaboration among socialist countries in the study of space;

· study of nuclear interaction of primary space radiation particles of more than 10¹² eV energy, with emulsion nuclei;

· study of chemical composition of primary space radiation particles (nuclear composition) of more than 10¹² eV energy;

· study of energy spectrum of primary space radiation particles (nuclear composition) of more than 10¹² eV energy;

· study of chemical composition and physical properties of meteoric perticles.

The big photographic emulsion unit of 1200 kg was mounted into the descent module. Eight containers with scientific hardware and traps for meteoric particles were mounted inside the descent module.

The spacecraft was in orbit for 6 days and then landed back to the Earth. It was enough for that phase of exploration.*