| Kosmos 277 | |
| Mission Type: | ABM radar target |
| Cospar Id: | 1969-033A |
| 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: | 91.2 minutes |
| Apsis: | gee |
Kosmos 277 (Russian: Космос 277 meaning Cosmos 277), known before launch as DS-P1-Yu No.20, was a Soviet satellite which was used as a radar calibration target for tests of anti-ballistic missiles. It was a 325kg (717lb) spacecraft, which was built by the Yuzhnoye Design Bureau, and launched in 1969 as part of the Dnepropetrovsk Sputnik programme.[1]
Kosmos 277 was launched from Site 133/1 at the Plesetsk Cosmodrome,[2] atop a Kosmos-2I 63SM carrier rocket. The launch occurred on 4 April 1969 at 13:00:04 UTC, and resulted in Kosmos 277's successful deployment into low Earth orbit.[3] Upon reaching orbit, it was assigned its Kosmos designation, and received the International Designator 1969-033A.
Kosmos 277 was operated in an orbit with a perigee of, an apogee of, 70.9 degrees of inclination, and an orbital period of 91.2 minutes.[1] It remained in orbit until it decayed and reentered the atmosphere on 6 July 1969.[4] It was the twentieth of seventy nine DS-P1-Yu satellites to be launched,[1] and the nineteenth of seventy two to successfully reach orbit.[5]