| Kosmos 51 | |
| Mission Type: | Technology Cosmic ray |
| Operator: | VNIIEM |
| Cospar Id: | 1964-080A |
| Satcat: | 00947 |
| Mission Duration: | 340 days |
| Spacecraft Type: | DS-MT |
| Manufacturer: | Yuzhnoye |
| Launch Mass: | 350 kg[1] |
| Launch Date: | 9 December 1964 23:02:00 GMT |
| Launch Rocket: | Kosmos 63S1 |
| Launch Site: | Kapustin Yar, Site 86/1 |
| Launch Contractor: | Yuzhnoye |
| Decay Date: | 14 November 1965 |
| Orbit Epoch: | 9 December 1964 |
| Orbit Reference: | Geocentric[2] |
| Orbit Regime: | Low Earth |
| Orbit Periapsis: | 262 km |
| Orbit Apoapsis: | 533 km |
| Orbit Inclination: | 48.8° |
| Orbit Period: | 92.5 minutes |
| Apsis: | gee |
Kosmos 51 (ru|Космос 51 meaning Cosmos 51), also known as DS-MT No.3 was a technology demonstration satellite which was launched by the Soviet Union in 1964 as part of the Dnepropetrovsk Sputnik programme. Its primary mission was to demonstrate an electric gyrodyne orientation system.[3] It also carried a scientific research package as a secondary payload, which was used to study cosmic rays and the luminosity of the stellar background.
It was launched aboard a Kosmos 63S1 rocket[4] from Site 86/1 at Kapustin Yar. The launch occurred at 23:02 GMT on 9 December 1964.[5]
Kosmos 51 was placed into a low Earth orbit with a perigee of, an apogee of, 48.8° of inclination, and an orbital period of 92.5 minutes. It decayed from orbit on 14 November 1965.[6] Kosmos 51 was the last of three DS-MT satellites to be launched. The first was lost in a launch failure on 1 June 1963, and the second was launched as Kosmos 31 on 6 June 1964.[7]