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Revision as of 20:24, 6 August 2005 by Mark83 (talk | contribs) (Satellite manufacturer & launch)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)SES-Astra (Société Européenne des Satellites-Astra) is a Luxembourg-based corporation which owns and operates the Astra series of geostationary satellites, which transmit approximately 1100 analogue and digital television and radio channels via 176 transponders to 91 million households across Europe. Formed in 1985 as SES, it was Europe's first private satellite operator.
Its slogan in 1997 was "Astra: The Satellite System". Nowadays it is "Your Satellite Connection to the World".
Orbital Positions
There are currently 13 Astra satellites in orbit, not all currently in service, located at the following positions in geosynchronous orbit:
- 5.2°E: Astra 1A. Originally sited at 19.2°E and used to broadcast the first European analogue direct-to-home TV services, this satellite is well past its expected lifetime and now in inclined orbit. Its last feed, RTL, terminates a few days prior to the 16th anniversary of its first broadcast, on 2nd December 2004 the satellite was finally retired.
- 19.2°E: 1C, 1E, 1F, 1G, 1H, 2C. This is the most common orbital position for direct-to-home satellite TV and radio transmission in Germany and Central Europe. 1G is also used for home satellite internet (with DVB modems) and the free-to-air TV and radio channels (Astra-Mosaic).
- 19.5°E: Astra 1B is currently positioned here, having drifted from 19.2°E since falling out of service.
- 23.5°E and 24.2°E: Astra 1D, 3A.
- 28.2°E: Astra 2A, 2B, 2D. BSkyB broadcast their Sky Digital direct-to-home television service to the United Kingdom and Republic of Ireland from this satellite constellation. Eutelsat's Eurobird satellite also operates close to this position.
Satellite manufacturer & launch
SES Astra operates satellites designed by Boeing Satellite Systems or BSS (formerly Hughes Space and Communications), Astrium and Alcatel Space.
Astra satellites within a family are not identical, for example of the Astra 2 satellites; 2A and 2C are BSS 601HPs, 2B is an Astrium Eurostar-2000 and 2D is a BSS 376.
The satellites are launched by Arianespace rockets from Kourou, French Guiana or International Launch Services Proton rockets from Baikonur, Kazakhstan. The satellites are launched into an elliptical "temporary transfer orbit" from where they use onboard propulsion to reach their final circular geostationary orbits at 36,000km (22,369 miles). Proton rockets fitted with a fourth stage propulsion unit are capable of launching the satellites several thousand kilometres higher (at the closest point of the elliptical orbit) than Ariane rockets. As a result most satellites launched in this way have to use less fuel to reach their geostationary orbit, increasing their flexibility.
See also
External links
- SES Astra - Official site
- Home satellite internet.
- Astra transponder footprints (To determine size requirements of a satellite dish - minimum diameter from 50 to 120 cm).