Development of Efir spacecraft with orbit life of 30 days was the next step in the field of space exploration. The research hardware was a monoblock with mass of 2450 kg containing detectors of charge, detectors of energy and a unit of electronics. Research data was transmitted vie telemetry channel to the ground stations.

In total, only 2 spacecraft of Efir type were put into space (in 1984 and 1986) and it was possible to record about 20 000 primary particles with the energy more than 1×10¹² eV. At that time such kind of information was obtained for the first time in the world in the field of space exploration. *

Today researches in the field of fundamental investigation of space are being successfully implemented with the help of Resurs-DK-1 №1 spacecraft under Pamela Project.*

* The article was written based on the materials taken from book - Spacecraft building:research and development by TsSKB-Progress/ edited by A.N.Kirilin- Samara: Publishing House, AGNI, 2011-p.280.