Oreol Credit - © Mark Wade

Upper atmosphere, auroral studies. Investigation of physical phenomena in the Earth's upper atmosphere at high latitudes and study of the nature of auroras.

This was a Soviet-French collaborative project, Russian code name Arkad. Launched by Kosmos-2, the spacecraft studied physics and the characteristics of the upper atmosphere. Instruments included Soviet/French magnetosphere and ionosphere experiments, equipment for studying the physical processes in the earth's magnetosphere and ionosphere, and study of the nature of polar aurora.

Typical orbit: 387 x 1697 km, 74 deg inclinaton. Mass: 590 kg (1,300 lb).

• 1971 December 27 - Oreol - Program: Aureole. Launch Site: Plesetsk. Launch Complex: LC132/2. Launch Vehicle: Kosmos 3. Mass: 630 kg (1,380 lb). Perigee: 391 km (242 mi). Apogee: 1,779 km (1,105 mi). Inclination: 74.00 deg. Period: 106.90 min.
  Upper atmosphere, auroral studies. Investigation of physical phenomena in the Earth's upper atmosphere at high latitudes and study of the nature of auroras.

• 1973 December 26 - Oreol 2 - Program: Aureole. Launch Site: Plesetsk. Launch Complex: LC132/2. Launch Vehicle: Kosmos 3. Mass: 550 kg (1,210 lb). Perigee: 387 km (240 mi). Apogee: 1,441 km (895 mi). Inclination: 74.00 deg. Period: 103.30 min.
  Continued investigations in the earth's upper atmosphere at high latitudes and study of the nature of polar aurorae begun on board the Oreol satellite in 1971.