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Intelsat III F-3 was a geostationary communications satellite operated by Intelsat. Launched in 1969 it was intended for operations over the Pacific Ocean; however, it spent most of its service life over the Indian Ocean at a longitude of 63 degrees east.[5]

Intelsat III F-3

Mission type	Communications
Operator	Intelsat
COSPAR ID	1969-011A
SATCAT no.	03674
Mission duration	5 years
Spacecraft properties
Spacecraft type	Intelsat III
Manufacturer	TRW
Launch mass	293 kg (646 lb)
BOL mass	151 kg (333 lb)
Power	183 watts
Start of mission
Launch date	February 6, 1969, 00:39:00 (1969-02-06UTC00:39Z) UTC[1]
Rocket	Delta M
Launch site	Cape Canaveral LC-17A
Contractor	NASA[2]
End of mission
Disposal	Decommissioned
Deactivated	c.December 14, 1979 (1979-12-15)[3]
Orbital parameters
Reference system	Geocentric
Regime	Geosynchronous Now Graveyard
Longitude	174° east (1969) 63° east (1969-c.1975)
Semi-major axis	47,100 km (29,300 mi)
Perigee altitude	39,921 km (24,806 mi)[4]
Apogee altitude	41,534 km (25,808 mi)[4]
Inclination	18.33 degrees[4]
Period	1695.49 minutes[4]
Epoch	January 23, 2015, 15:01:00 UTC[4]
Intelsat III ← Intelsat III F-2 Intelsat III F-4 →

The third of eight Intelsat III satellites to be launched, Intelsat III F-3 was built by TRW. It was a 293-kilogram (646 lb) spacecraft, with its mass reducing to 151 kilograms (333 lb) by entry into service as it burned propellant to reach its final orbit. The satellite carried an SVM-2 apogee motor for propulsion and was equipped with two transponders powered by body-mounted solar cells generating 183 watts of power.[6] It was designed for 5 years of service life.[7]

The launch of Intelsat III F-3 made use of a Delta M rocket flying from Launch Complex 17A at the Cape Canaveral Air Force Station. The launch, which was conducted by NASA, took place at 00:39:00 UTC on February 6, 1969, with the spacecraft entering a geosynchronous transfer orbit.[1] Shortly after launch, Intelsat III F-3 fired its apogee motor to achieve geostationary orbit.

Intended to be operated over the Pacific Ocean at a longitude of 174° east, Intelsat III F-3 was moved to the less important Indian Ocean slot at 63° east after only three months in orbit due to concerns regarding its reliability.[8] The satellite was only regarded as partially operable; however, it remained in service until April 1979, before being decommissioned in December of that year.[3][8]

At the end of its service life, Intelsat III F-3 was raised into a higher orbit to reduce the probability of it colliding with an operational spacecraft. As of February 3, 2014 it remains in orbit, with a perigee of 39,935 kilometers (24,814 mi), an apogee of 41,521 kilometers (25,800 mi), inclination of 18.63 degrees and an orbital period of 28.25 hours.[4]

References

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