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Astra 1D is a
geostationary A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...
communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Rad ...
launched in 1994 by the Société Européenne des Satellites ( SES). , the craft remains in service for occasional use. Astra 1D was the fourth, and under original plans, last Astra
communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Rad ...
from SES. It was launched to SES' original solitary operational position at 19.2° East, and was intended as an in-orbit spare for Astra's
Astra 1A Astra 1A was the first satellite launched and operated by SES (Société Européenne des Satellites), launched in December 1988. During its early days, it was often referred to as the Astra Satellite, as SES only operated one satellite origi ...
, 1B and 1C and to carry
digital TV Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adv ...
transmissions. However, development of digital reception equipment in Europe was not sufficiently advanced for Astra 1D to be SES' first digital satellite (the later Astra 1E fulfilled that role) and demand for additional capacity for both British and German television channels led to 12 of the satellite's transponders being leased to broadcast analogue TV channels before the satellite had been launched.


History

After launch to 19.2° East, Astra 1D served two periods as a spare at the Astra 28.2°E position colocated with Astra 2A, for seven months in 1998 and for 13 months from December 1999. In between these two periods, it returned to the Astra 19.2°E position. During this time, some small numbers of
transponders In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight trans ...
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° East where it spent over two years carrying little more than test cards or feeds, until a move to 23° East (November 2003) and then 23.5° East (September 2004) where Euro1080 began to use it as their main transmitting craft. When the satellite originally went on air in January 1995, several of its transponders were used by
British Sky Broadcasting Sky UK Limited (formerly British Sky Broadcasting Limited (BSkyB)), trading as Sky, is a British broadcaster and telecommunications company that provides television, broadband internet, fixed line and mobile telephone services to consumers a ...
for new channels such as Granada Talk TV. These transponders broadcast on frequencies outside (below) the tuning range offered by the original Sky set-top-box receiver (with a 950-1750
MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...
IF tuning range) and a standard Astra
Low-noise block downconverter A low-noise block downconverter (LNB) is the receiving device mounted on satellite dishes used for satellite TV reception, which collects the radio waves from the dish and converts them to a signal which is sent through a cable to the receiver ...
(LNB) (with a 10.00 GHz
local oscillator In electronics, the term local oscillator (LO) refers to an electronic oscillator when used in conjunction with a Frequency mixer, mixer to change the frequency of a signal. This frequency conversion process, also called Heterodyne, heterodyning ...
) so Sky produced a frequency shifter ("ADX Plus Channel Expander"), comprising a small box connected between the LNB and the receiver (and powered by the receiver) with a single manual switch to select between Astra 1A and Astra 1D reception. Switched to Astra 1D reception, this shifted up the IF signal from the LNB by 250 MHz to bring the new frequencies within the receiver's tuning range. Subsequent Sky receivers had an 'extended' 950-2150 MHz IF tuning range and were used with an 'Enhanced LNB' with a 9.75 GHz local oscillator to enable reception of all the transponders used on the Astra 1A-1D satellites. In November 2007, Astra 1D was replaced at the Astra 23.5°E position by Astra 1E, and was moved to 31.5° East, where it operated in inclined orbit, to replace Optus A3, and was joined in April 2008 by Astra 5A to officially open the Astra 31.5°E position. On 16 January 2009, Astra 5A suffered a technical failure and all traffic ceased. Much of it (especially channels for German cable service, Kabel Deutschland) transferred to Astra 23.5° East as Astra 1D was not suitable for the transmission of these services because it was in an inclined orbit. In May 2009, Astra 2C was moved from the 28.2° East position to Astra 31.5° East to take over Astra 5A's mission with Astra 1D as ultimate backup. In June 2010, Astra 1G was moved from Astra 23.5° East to Astra 31.5° East (following the launch of Astra 3B to 23.5° East), where it could take over all broadcasting activity from Astra 2C, releasing Astra 2C for backup, and releasing Astra 1D for use elsewhere. Astra 1D then commenced movement westwards and in August 2010 arrived at 1.8° East where, with
Astra 1C Astra 1C was a geostationary communications satellite launched in 1993 by SES. The satellite remained in service until 2011 and is now derelict. History Astra 1C was the third communications satellite placed in orbit by SES, and was origina ...
at 2.0° East it was used for occasional traffic such as outside broadcast news feeds. Astra 1D returned 23.5° East in 2012 with two transponders active for several months (both carrying the
Luxembourg Luxembourg, officially the Grand Duchy of Luxembourg, is a landlocked country in Western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France on the south. Its capital and most populous city, Luxembour ...
terrestrial channel,
RTL Télé Lëtzebuerg RTL may refer to: Media * RTL Group, a European TV, radio, and production company *** List of RTL Group's television stations (including part-owned channels) *** List of RTL Group's radio stations ** RTL Lëtzebuerg, usually referred to simply ...
). In June 2013, the satellite moved east from 23.5° East (although it remained listed in the SES website as at this position ) to 52.2° East. In February 2014, Astra 1D began moving westward, reaching its destination of 67.5° West in June 2014, where it was joined by Astra 1H in August 2014, moved from 19.2° East. Both Astra 1D and Astra 1H were moved close to NSS-806 at 47.5° West in the Spring/Summer of 2015. In 2017, Astra 1D was moved to 73° West. Since November 2021, 1D has been non-operational and drifting west at approximately 4.8°/day.Real Time Satellite Tracking And Predictions
Accessed 25 November 2021


Transponders

The channels broadcast on Astra 1D during its time at 19.2° East (1994-2000) include:


See also

* Astra 31.5°E previous orbital position * Astra 19.2°E original orbital position * SES (operator) * Astra satellite family


References


External links


Official SES websiteHighlights of SES historySES fleet information and mapSES guide to channels broadcasting on Astra satellites
{{Orbital launches in 1994 Astra satellites Communications satellites in geostationary orbit Satellites using the BSS-601 bus 1994 in Luxembourg Satellites of Luxembourg Spacecraft launched in 1994