Kosmos 670 ( meaning Cosmos 670) was an unmanned Soyuz 7K-S test. It used a new and unique inclination of 50.6 degree. The experience from these flights were used in the development of the successor program Soyuz spacecraft the Soyuz 7K-ST. Mission parameters Spacecraft: 7K-S Mass: 6700 kg Crew: None Launched: August 6, 1974 Landed: August 8, 1974 23:59 UTC. Perigee: 221 km Apogee: 294 km Inclination: 50.6 deg Duration: 2.99 days See also Cosmos 772 Cosmos 869 References Kosmos 0670 1974 in the Soviet Union Spacecraft launched in 1974 Soyuz uncrewed test flights