| Kosmos 421 | |
| Mission Type: | ABM radar target |
| Cospar Id: | 1971-044A |
| Spacecraft Type: | DS-P1-Yu |
| Manufacturer: | Yuzhnoye |
| Launch Date: | UTC |
| Launch Rocket: | Kosmos-2I 63SM |
| Launch Site: | Plesetsk 133/1 |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Low Earth |
| Orbit Inclination: | 70.9 degrees |
| Orbit Period: | 91.65 minutes |
| Apsis: | gee |
Kosmos 421 (ru|Космос 421 meaning Cosmos 421), known before launch as DS-P1-Yu No.48, was a Soviet satellite which was launched in 1971 as part of the Dnepropetrovsk Sputnik programme. It was a 325kg (717lb) spacecraft, which was built by the Yuzhnoye Design Bureau, and was used as a radar calibration target for anti-ballistic missile tests.[1]
Kosmos 421 was successfully launched into low Earth orbit on 19 May 1971, with the rocket lifting-off at 10:20:00 UTC.[2] The launch took place from Site 133/1 at the Plesetsk Cosmodrome,[3] and used a Kosmos-2I 63SM carrier rocket.
Upon reaching orbit, it was assigned its Kosmos designation, and received the International Designator 1971-044A.[4]
Kosmos 421 was the forty-second of seventy nine DS-P1-Yu satellites to be launched,[1] and the thirty-eighth of seventy two to successfully reach orbit.[5] It was operated in an orbit with a perigee of, an apogee of, 70.9 degrees of inclination, and an orbital period of 91.65 minutes.[1] It remained in orbit until it decayed and reentered the atmosphere on 8 November 1971.[6]