Telstar is a global network of communications satellites originally operated by AT&T Skynet, later Loral Skynet. Telstar 1 (Figure 1), owned by AT&T and flown by NASA, was the first commercial communications satellite. It was a mere 81 cm (32 in) in diameter and weighed only 77 kilograms (170 pounds). Launched on 10 July 1962, it entered an orbit that carried it round the Earth once every 158 minutes. Telstar 1 relayed the first transatlantic television transmissions between Andover, Maine, and stations in Goonhilly, England, and Pleumeur-Bodou, France.

 

Although both Telstar 1 and Telstar 2 were an immediate commercial success, the problem lay in tracking them: they orbited the Earth roughly once every three hours and thus had to be continuously followed by ground station antennae. Syncom 2 was a great advance on these early Telstars because it did not have to be tracked.

 

Telstar 5 (Figure 2), 6, and 7, serve the United States, southern Canada, Mexico, and the Caribbean. Telstar 5 and 6 each carry 24 C-band and 28 Ku-band transponders (see frequency bands, while Telstar 7 carries 24 C-band and 24 Ku-band transponders but achieves the same radio-frequency transmitter power, of 3200 watts, by using more powerful components. In 2003, Loral announced an agreement to sell Telstar 5, 6 and 7 to Intelsat, which now operates the satellites now as Intelsat Americas 5, 6 and 7. Telstar 8, to be operated as Intelsat America 8, will be launched in 2004 from Sea Launch's Odyssey Launch Platform by a Zenit-3SL rocket. It is one of the most powerful communications satellites ever built, with a total of 92 Ku-band, C-band, and Ka-band transponders, a transmitter power of at least 16,000 watts, and a mass of 5,500 kilograms. Telstar 8 wil replace Telstar 402R, which Loral declared lost in 2003, at 89° W and provide coverage across North and South America.

 

spacecraft	launch date	launch vehicle	launch site	orbit	mass (kg)
Telstar 1	Jul 10, 1962	Delta B	Cape Canaveral	945 × 5,643 km × 45°	77
Telstar 2	May 7, 1963	Delta B	Cape Canaveral	972 × 10,802 km × 43°	79
Telstar 3A / Arabsat 1E	Jul 28, 1983	Delta 3925	Cape Canaveral	GSO at 76° W	625
Telstar 3C	Aug 30, 1984	Shuttle STS-41	Cape Canaveral	GSO at 125° W	625
Telstar 3D	Jun 17, 1985	Shuttle STS-51	Cape Canaveral	GSO at 76° W	630
Telstar 401	Dec 16, 1993	Atlas IIAS	Cape Canaveral	GSO at 97° W	3,375
Telstar 402	Sep 9, 1994	Ariane 421	Kourou	lost in orbit	3,485
Telstar 402R	Sep 24, 1995	Ariane 421	Kourou	GSO at 89° W	3,410
Telstar 5	May 24, 1997	Proton 2KDM4	Baikonur	GSO at 97° W	3,600
Telstar 6	Feb 15, 1999	Proton 2KDM3	Baikonur	GSO at 93° W	3,763
Telstar 7	Sep 25, 1999	Ariane 44LP	Kourou	GSO at 127° W	3,790
Telstar 10 / APStar 2R	Oct 17, 1997	CZ-3B	Xi Chang	GSO at 76.5° E	3,700
Telstar 11 / Orion 1	Nov 29, 1994	Atlas IIA	Cape Canaveral	GSO at 37.5° W	2,361
Telstar 12 / Orion 2	Oct 19, 1999	Ariane 44LP	Kourou	GSO at 15° W	3,814
Telstar 13 / Echostar 9	Aug 8, 2003	Zenit 3SL	Sea Launch	GSO at 121° W	4,737
Telstar 14 / Estrala do Sul 1	Jan 11, 2004	Zenit 3SL	Sea Launch	GSO at 63° W	4,694
Telstar 18 / APStar 5	Jun 28, 2004	Zenit 3SL	Sea Launch	GSO at 138° E	4,640