Kosmos 311

Mission type	ABM radar target
COSPAR ID	1969-102A
SATCAT no.	04252
Spacecraft properties
Spacecraft type	DS-P1-Yu
Manufacturer	Yuzhnoye
Launch mass	325 kilograms (717 lb)
Start of mission
Launch date	24 November 1969, 11:00:04 (1969-11-24UTC11:00:04Z) UTC
Rocket	Kosmos-2I 63SM
Launch site	Plesetsk 133/1
End of mission
Decay date	10 March 1970 (1970-03-11)
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Perigee altitude	263 kilometres (163 mi)
Apogee altitude	438 kilometres (272 mi)
Inclination	71 degrees
Period	91.5 minutes

Kosmos 311 (Russian: Космос 311 meaning Cosmos 311), known before launch as DS-P1-Yu No.27, was a Soviet satellite which was launched in 1969 as part of the Dnepropetrovsk Sputnik programme. It was a 325-kilogram (717 lb) spacecraft, which was built by the Yuzhnoye Design Bureau, and was used as a radar calibration target for anti-ballistic missile tests.^[1]

Launch

Kosmos 311 was launched from Site 133/1 at the Plesetsk Cosmodrome,^[2] atop a Kosmos-2I 63SM carrier rocket. The launch occurred on 24 November 1969 at 11:00:04 UTC, and resulted in the successful deployment of Kosmos 311 into low Earth orbit.^[3] Upon reaching orbit, it was assigned its Kosmos designation, and received the International Designator 1969-102A.

Kosmos 311 was operated in an orbit with a perigee of 263 kilometres (163 mi), an apogee of 438 kilometres (272 mi), 71 degrees of inclination, and an orbital period of 91.5 minutes.^[1][4] It remained in orbit until it decayed and reentered the atmosphere on 10 March 1970.^[4] It was the twenty-seventh of seventy nine DS-P1-Yu satellites to be launched,^[1] and the twenty-fifth of seventy two to successfully reach orbit.^[5]