Cosmos 312 was the fifth of the Soviet Sfera satellites (thus also known as Sfera 5), launched on 24 November 1969. The Sfera (sphere) program was a series of geodetic satellites used to improve the accuracy of maps – and of long-range weapons systems.

The satellites held flashing lights to indicate their position relative to the surrounding starfields and thus used to measure the position of points on the earth’s surface to within a few dozen meters.

Still in orbit today, Cosmos 312 is accompanied by the rocket booster that launched it.