| OGCh | ||
The OGCh was the only orbiting military nuclear weapon ever deployed, although in order to remain legal under international treaties it was a 'fractional orbital' weapon. Although American infrared early warning satellites invalidated the 'surprise attack' component of the concept, 18 missiles were operational from 1969 to 1983. The Global Rocket 1 (GR-1) requirement of 1961 called for a system to place a large nuclear warhead equipped with a deorbit rocket stage into a low earth orbit of 150 km altitude. The warhead could approach the United States from any direction, below missile tracking radar, so little warning was available. Not only could such a missile hit any point on earth, but the enemy would also be uncertain when it would be deorbited onto target. The disadvantages were greater complexity, lower accuracy, and the need to use a lighter warhead in comparison to an ICBM. Furthermore American development and deployment of infrared early-warning satellites in the 1970's invalidated the warning advantage. Flight trials of the system began on 16 October 1965 from silos at LC-160 and LC-162 at Baikonur. Since orbiting of nuclear weapons was a violation of international treaty, the Soviet Union conducted all tests on a 'fractional orbit' basis - i.e. the test warheads were deorbited after less than one orbit of the earth. The launches were however logged and tracked as satellites by international treaty. There were four launches in 1966 and 10 in 1967. The United States only publicly noted the probable FOBS mission of the tests on 3 November 1967. The system was formally accepted for military service on 19 November 1968. A military regiment to operate the missiles was formed in August 1971. The system was in service at 18 silos at Baikonur from 25 August 1969 to January 1983. Under SALT-2 12 of these silos were demolished, the remaining six being retained for launch of R-36M's converted to orbital launch vehicle use. In common with other R-36 versions, the missile had a 7.5 year guaranteed fuelled storage life and a five minute reaction time. The 8F021 orbiting warhead had the Russian acronym OGCh. It consisted of an SU equipment unit which oriented the spacecraft in orbit and autonomously determined when to make the braking maneuver to bring the re-entry vehicle down from orbit. The SU included an inertial navigation system and a radar altimeter which measured the altitude of the orbit and thereby determined when to make the braking maneuver. A solid fuel cartridge then spun up the turbine assembly of the liquid propellant (N2O4/UDMH) braking engine. Orientation was by 4 + 4 thrusters using turbine exhaust gases. Typical orbit: 139 x 270 km, 49.6 deg inclinaton. Mass: 1,700 kg (3,700 lb). Associated Launch Vehicle: R-36-O. OGCh Chronology
Bibliography and Further Reading
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