Astra 1D

Astra 1D was the fourth, and under original plans, last communications satellite from Société Européenne des Satellites (SES), now SES Astra. It was launched to Astra's original solitary operational position at 19.2°E, and was intended as an in-orbit spare for Astra's 1A, 1B and 1C. However, demand for additional capacity for both British and German television channels, plus the extension of the receivable segment of the Ku band by 250 MHz on most consumer equipment led to the satellite becoming regularly used, and the launch of a further four Astra 1 satellites. The launch of these later craft returned 1D to a role as a "troubleshooter" for the Astra fleet.

It later served two periods as a spare at the Astra 28.2°E position colocated with Astra 2A, during mid-1998 and for most of 2000. Inbetween these two periods, it returned to the Astra 19.2°E position. During this time, some small numbers of transponders were used for regular service. After other Astra craft (Astra 2B, Astra 2D) either arrived or were ordered for the slot, it moved to 24.2°E where it spent almost two years carrying little more than test cards or feeds, until a move to 23°E (September 2003) and then 23.5°E (November 2004) [cite web |url=http://www.tbs-satellite.com/tse/online/sat_astra_1d.html|title=Astra 1D factsheet|publisher=The Satellite Encyclopedia | accessmonthday= September 22 |accessyear=2008] where Euro1080 began to use it as their main transmitting craft.

As of November 11 2007, Astra 1D has been replaced at the Astra 23.5°E position by Astra 1E, which has taken on the services carried by its predecessor. Astra 1D is still in orbit and it is currently at the Astra 31.5°E position, in inclined orbit and colocated with Astra 5A.

When the satellite originally went on air, several of its transponders were used by British Sky Broadcasting for new channels such as Granada Plus. Since these channels used frequencies that were not available on the original Sky receivers due to being outside the original BSS band, Sky issued viewers with frequency shifters ("ADX Plus Channel Expanders"), comprising small boxes the size of a cigarette packet with a single switch and an on/off LED. When connected between the dish and the receiver (and powered by the receiver) these allowed viewers to switch manually between the Astra 1A and Astra 1D frequency bands - precisely 250 MHz.

References

ee Also

*Astra 5A co-located satellite
*Astra 31.5°E orbital position
*SES Astra satellite owner

External Links

* [http://www.ses-astra.com SES Astra Website]
* [http://www.ses-astra.com/consumer/en/how-to-receive-astra/index.php SES Astra guide to receiving Astra satellites]
* [http://www.flysat.com/astra1d.php Astra 1D Frequency chart on FlySat.com]