Kosmos 261


Kosmos 261
Mission typeAeronomy
COSPAR ID1968-117A
SATCAT no.03624Edit this on Wikidata
Spacecraft properties
Spacecraft typeDS-U2-GK
Launch mass347 kilograms (765 lb)[1]
Start of mission
Launch date19 December 1968, 23:55:00 (1968-12-19UTC23:55Z) UTC
RocketKosmos-2I 63SM
Launch sitePlesetsk 133/1
End of mission
Decay date12 February 1969 (1969-02-13)
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee altitude201 kilometres (125 mi)
Apogee altitude611 kilometres (380 mi)
Inclination71 degrees
Period92.68 minutes

Kosmos 261 (Russian: Космос 261 meaning Cosmos 261), also known as DS-U2-GK No.1, was a Soviet satellite which was launched in 1968 as part of the Dnepropetrovsk Sputnik programme. It was a 347-kilogram (765 lb) spacecraft,[1] which was built by the Yuzhnoye Design Bureau, and was used to study the density of air in the upper atmosphere, and investigate aurorae.[1]

A Kosmos-2I 63SM carrier rocket was used to launch Kosmos 261 into low Earth orbit from Site 133/1 at the Plesetsk Cosmodrome.[2] The launch occurred at 23:55:00 UTC on 19 December 1968, and resulted in the successful insertion of the satellite into orbit.[3] Upon reaching orbit, the satellite was assigned its Kosmos designation, and received the International Designator 1968-117A.[4] The North American Aerospace Defense Command assigned it the catalogue number 03624.

Kosmos 261 was the first of two DS-U2-GK satellites to be launched.[1][5] It was operated in an orbit with a perigee of 201 kilometres (125 mi), an apogee of 611 kilometres (380 mi), 71 degrees of inclination, and an orbital period of 92.68 minutes.[6] It decayed from orbit and reentered the atmosphere on 12 February 1969.[6]

See also


  1. ^ a b c d Wade, Mark. "DS-U2-GK". Encyclopedia Astronautica. Archived from the original on 8 January 2010. Retrieved 26 December 2009.
  2. ^ McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 26 December 2009.
  3. ^ Wade, Mark. "Kosmos 2". Encyclopedia Astronautica. Archived from the original on 8 July 2012. Retrieved 26 December 2009.
  4. ^ "Cosmos 261". NSSDC Master Catalog. US National Space Science Data Center. Retrieved 26 December 2009.
  5. ^ Krebs, Gunter. "DS-U2-GK". Gunter's Space Page. Retrieved 26 December 2009.
  6. ^ a b McDowell, Jonathan. "Satellite Catalog". Jonathan's Space Page. Retrieved 26 December 2009.