| Revision as of 21:23, 6 August 2005 editMark83 (talk | contribs)Administrators24,913 edits Logo, rmv informal language← Previous edit | Revision as of 21:11, 7 August 2005 edit undoMark83 (talk | contribs)Administrators24,913 edits Removed 5.2E from Orbital positions. Added failure of 1K launchNext edit → | ||
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| ==Orbital Positions== | ==Orbital Positions== | ||
| ] 601HP satellites. 2A provides primarily DTH services to the UK and Ireland. 2C provides coverage of continental Europe and the British Isles]] | ] 601HP satellites. 2A provides primarily DTH services to the UK and Ireland. 2C provides coverage of continental Europe and the British Isles]] | ||
| There are currently |
There are currently 12 Astra satellites in orbit, not all currently in service, located at the following positions in ]: | ||
| ⚫ | *'''19.2°E''' <br>1C, 1E, 1F, 1G, 1H, 2C. This is the most common orbital position for direct-to-home satellite TV and radio transmission in ] and Central Europe. 1G is also used for home ] (with ] modems) and the ] TV and radio channels (Astra-Mosaic). | ||
| *5.2]: 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 ]. Its last feed, ], terminates a few days prior to the 16th anniversary of its first broadcast, on 2nd December 2004 the satellite was finally retired. | |||
| ⚫ | *'''19.5°E''' <br>Astra 1B is currently positioned here, having drifted from 19.2°E since falling out of service. | ||
| ⚫ | *19.2°E |
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| ⚫ | *'''23.5°E and 24.2°E''' <br>Astra 1D, 3A. | ||
| ⚫ | *19.5°E |
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| ⚫ | *'''28.2°E''' <br>Astra 2A, 2B, 2D. ] broadcast their ] direct-to-home television service to the ] and ] from this satellite constellation. ]'s Eurobird satellite also operates close to this position. | ||
| ⚫ | *23.5°E and 24.2°E |
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| ⚫ | *28.2°E |
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| ==Satellite manufacturer & launch== | ==Satellite manufacturer & launch== | ||
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| The satellites are launched by ] ] from ], ] or ] ]s from ], ]. 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. | The satellites are launched by ] ] from ], ] or ] ]s from ], ]. 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. | ||
| ===Failures=== | |||
| Astra 1K, the largest commerical communciations satellite ever built, was ordered by SES-Astra in 1997. It was launched by Proton rocket on ] 2002. The rocket lifted off as planned and reached its "parking orbit" at which point the final stage of the rocket was to initiate a second burn to transfer the satellite to its geostationary orbit. This did not occur and the satellite was released into the parking orbit, making it unuseable. The only way to recover the satellite was the use of an orbiter, however this was rejected. On ] SES Astra instructed ] (the manufacturer) and the French Space Agency ] to deorbit the satellite, it broke up on re-entry over the ]. | |||
| ==See also== | ==See also== | ||
Revision as of 21:11, 7 August 2005
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". It is currently "Your Satellite Connection to the World".
Orbital Positions
There are currently 12 Astra satellites in orbit, not all currently in service, located at the following positions in geosynchronous orbit:
- 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.
Failures
Astra 1K, the largest commerical communciations satellite ever built, was ordered by SES-Astra in 1997. It was launched by Proton rocket on November 26 2002. The rocket lifted off as planned and reached its "parking orbit" at which point the final stage of the rocket was to initiate a second burn to transfer the satellite to its geostationary orbit. This did not occur and the satellite was released into the parking orbit, making it unuseable. The only way to recover the satellite was the use of an orbiter, however this was rejected. On December 10 SES Astra instructed Alcatel Space (the manufacturer) and the French Space Agency CNES to deorbit the satellite, it broke up on re-entry over the Pacific Ocean.
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).