Astra 2D

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Astra 2D
Operator SES Astra
SATCAT № 26638
Mission duration 12 years[1]
Spacecraft properties
Bus HS-376
Manufacturer Hughes
Launch mass 1,420 kilograms (3,130 lb)
BOL mass 824 kilograms (1,817 lb)
Power 1,600 watts
Start of mission
Launch date 19 December 2000 (2000-12-19)
Rocket Ariane 5G V138
Launch site Kourou ELA-3
Contractor Arianespace
Orbital parameters
Reference system Geocentric
Regime Geosynchronous
Longitude 24°E (testing)
28.2°E (current)
Perigee 35,786 kilometres (22,236 mi)[2]
Apogee 35,798 kilometres (22,244 mi)[2]
Inclination 1.88 degrees[2]
Period 1436.09 minutes[2]
Epoch 14 December 2014, 04:25:24 UTC[2]
Band 16 Ku band
Bandwidth 26 MHz
TWTA power 39 watts

Astra 2D is one of the Astra communications satellites owned and operated by SES, and located at 28.2° east in the Clarke Belt. It is a Hughes HS-376 craft, and was launched from the Guiana Space Centre in December 2000 to join Astra 2A and Astra 2B at 28.2°E, where it has remained for its active life.

As of February 2013, Astra 2D carries no regularly active transponders[3] and is operating in an inclined orbit.[4]

In service[edit]

While active, most of Astra 2D's transponders were used to provide television channels available on the Sky Digital satellite service to both Ireland and the United Kingdom, as well as the non-subscription service, Freesat. Provision of rights-sensitive broadcasts Free to air was made possible by the satellite's beam that was tightly focused on Ireland and the United Kingdom. However, surrounding countries had the ability to pick up the signal (dependent on suitably sized satellite dishes) and so could still access Freesat from outside the UK. Some channels on 2D were encrypted with Videoguard (a proprietary encryption method by the NDS Group) and only Sky Digiboxes with valid cards, or standard hardware with non-approved (with respect to the Sky/NDS end-user contract) "Dragon", or "T-Rex" conditional-access module can decode these channels.

The BBC broadcast all of its domestic television channels (including BBC HD and the regional variations) from the Astra 2D satellite, except the BBC News Channel and BBC Parliament which broadcast from Astra 2A. All domestic BBC channels have been free to air since 29 July 2003.

ITV also broadcast all its television channels (including regional variations of ITV1, and STV and UTV) from the Astra 2D satellite. All ITV channels have been free to air from 1 November 2005, although some regions reverted to Free-To-View encryption in 2008 when their lease on one 2D transponder could not be renewed.

Channel 4 broadcast most of its channels free to air from this satellite, including Channel 4, Channel 4+1, E4, More4 and Film4 along with their timeshift variants. All were unencrypted apart from the feeds of Channel 4, Channel 4+1, E4 and E4+1 intended for viewers in Ireland, which remain encrypted.

From November 2008, Five began to transmit free to air for the first time on Astra 2D, using borrowed space on a BBC transponder, allowing the channel to join Freesat.

End of service[edit]

With a projected lifetime of 12 years, Astra 2D was expected to leave regular operational service towards the end of 2012 or the beginning of 2013 and so the Astra 1N satellite, designed for operation at Astra 19.2°E and launched in August 2011, was initially positioned at 28.2°E to temporarily replace Astra 2D until the start of service of its long-term replacement, Astra 2F, which was launched in September 2012.[5]

Astra 1N started commercial service at 28.2°E in October 2011[6] with transponder testing in October and November. Channels on Astra 2D started to transfer to Astra 1N in December with Channel 5 (plus 5* and 5USA), the Channel 4 family and ITV channels all moving to the new satellite over the next two months. On 24 February 2012 the last remaining channels on Astra 2D (the BBC channels) switched off and started transmission from Astra 1N.[7]

As of June 2013, Astra 2D remains in position at 28.2°E, with no transponder activity.[8]

See also[edit]


External links[edit]