| Kosmos 123 | |
| Mission Type: | ABM radar target |
| Cospar Id: | 1966-061A |
| Satcat: | 02295 |
| Mission Duration: | 155 days |
| Spacecraft Type: | DS-P1-Yu |
| Manufacturer: | Yuzhnoye |
| Launch Mass: | 325 kg |
| Launch Date: | 8 July 1966, 05:31:00 GMT |
| Launch Rocket: | Kosmos-2I 63S1 |
| Launch Site: | Kapustin Yar, Site 86/1 |
| Launch Contractor: | Yuzhnoye |
| Decay Date: | 10 December 1966 |
| Orbit Epoch: | 8 July 1966 |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Low Earth |
| Orbit Periapsis: | 256 km |
| Orbit Apoapsis: | 512 km |
| Orbit Inclination: | 48.8° |
| Orbit Period: | 92.2 minutes |
| Apsis: | gee |
Kosmos 123 (ru|Космос 123 meaning Cosmos 123), also known as DS-P1-Yu No.5 was a Soviet satellite which was used as a radar calibration target for tests of anti-ballistic missiles.[1] It was built by the Yuzhnoye Design Bureau, and launched in 1966 as part of the Dnepropetrovsk Sputnik programme.[2]
A Kosmos-2I 63S1 carrier rocket was used to launch Kosmos 123.[3] The launch occurred from Site 86/1 at Kapustin Yar, at 05:31 GMT on 8 July 1966.[4] and following its successful arrival in orbit the spacecraft received its Kosmos designation; along with the International Designator 1966-061A[5] and the Satellite Catalog Number 02295.
Kosmos 123 separated from the carrier rocket into a low Earth orbit with a perigee of, an apogee of, an inclination of 48.8°, and an orbital period of 92.2 minutes.[6] It decayed from orbit on 10 December 1966.[7] Kosmos 123 was the sixth of seventy-nine DS-P1-Yu satellites to be launched,[2] and the fifth of seventy-two to successfully reach orbit.