Intelsat 4

Part of the Intelsat program

The Intelsat 4 series continued the growth of the Intelsat communications network. The series included the first commercial communications satellite built outside of the United States (F4 was assembled by British Aircraft Corporation). Operational lifetimes were: F1 - 3 years for ITSO, then leased out; F2 - 12 years; F3 - 12 years, then placed into orbital storage; F4 - over 7 years; F5 - over 7 years ; F6 - 0 years (failed to orbit); F7 - over 6 years, then placed into orbital storage; F8 - 9 years (?).

Spacecraft
Spin stabilized with a despun antenna structure. Hydrazine propulsion system. Passive thermal control. Body mounted solar cells.

Payload
Twelve transponders. Multiple access. 4000 voice circuits or 2 TV channels.

Country of Origin	International
Customer/User	ITSO
Manufacturer(s)	Hughes
Size	Cylinder: 2.8 m long (5.3 m w/antenna), 2.4 m diameter
Orbit	F1: GEO over Indian Ocean then moved over Atlantic / F2: GEO over Atlantic / F3: GEO over Atlantic / F4: GEO over Pacific / F5: GEO over Indian Ocean / F6: FTO / F7: GEO over Atlantic / F8: GEO over Pacific
Design Life	7 years

Launch Facts

Name	Int'l Desig.	Date	Site	Vehicle	Orbit	Mass(kg)
Notes
Intelsat 4 F-2	1971-006A	1/26/71	ESMC	Atlas Centaur	GEO	706
24.5 deg W
Intelsat 4 F-3	1971-116A	12/20/71	ESMC	Atlas Centaur	GEO	1410
Over Atlantic
Intelsat 4 F-4	1972-003A	1/23/72	ESMC	Atlas Centaur	GEO	1410
Over Pacific
Intelsat 4 F-5	1972-041A	6/13/72	ESMC	Atlas Centaur	GEO	1410
Over Indian Ocean
Intelsat 4 F-7	1973-058A	8/23/73	ESMC	Atlas Centaur	GEO	1410
Over Atlantic Ocean
Intelsat 4 F-8	1974-093A	11/21/74	ESMC	Atlas Centaur	GEO	1410
Intelsat 4 F-6	none	2/20/75	ESMC	Atlas Centaur	FTO	1410
Intelsat 4 F-1	1975-042A	5/22/75	ESMC	Atlas Centaur	GEO	727