Sirius (satellite)

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Not to be confused with Sirius Satellite Radio.

Sirius was a constellation of communications satellites operated at 5°E in geostationary orbit (GEO) by NSAB (later SES Sirius, and now a non-autonomous part of SES, owner and operator of the Astra satellites). They carried digital satellite television to the countries of Scandinavia, Baltic states, eastern Europe and Africa, including the Viasat pay TV system, along with several pay TV packages for eastern Europe, the TopTV package for Africa, a number of Ukrainian channels and the national Latvian and Lithuanian channel service free-to-air.

Satellites[edit]

Sirius 3[edit]

Sirius 3 is currently stationed at 51.2° East (0°00′N 51°12′E / 0°N 51.2°E / 0; 51.2) in an inclined orbit.[1] Sirius 3 was leased to SES immediately after its launch on October 5, 1998 for a period of 12 months (after which it was moved to its original destination of 5°E) to provide capacity at 28.2°E and to back up Astra 2A, pending the launch of Astra 2B on September 14, 2000.[2]

Sirius 4[edit]

A fourth satellite, Sirius 4, was ordered in 2005 and launched at 22:39:47 on 17 November 2007. It carries 52 active Ku-band transponders and two active Ka-band transponders.[3] Sirius 4 was built by Lockheed Martin Space Systems based upon the A2100AX design.[4]

Among the services carried are Viasat and Viasat Ukraine which has used the Sirius satellites for their digital platform since its launch.

Sirius 4 was renamed to Astra 4A in June 2010, when the SES took full ownership and control of SES Sirius.[5]

Retired satellites[edit]

Sirius 1[edit]

Sirius 1 (later Sirius W) was purchased from British Sky Broadcasting after Sky Television's merger with British Satellite Broadcasting (the merger was conducted on Sky's terms and BSB's satellites were sold in favour of Sky's leased Astra satellite operations). The satellite had previously operated as Marcopolo 1. It operated at 5° east from 1994 until 2000, when it was moved to 13° west. It operated here before being dumped to graveyard orbit in 2003.

Sirius 2[edit]

Main article: Astra 5A

Sirius 2 was manufactured by Aérospatiale and launched from Kourou on November 12, 1997 to replace the Tele-X satellite. It is of the model Spacebus 3000B2 and has 32 Ku band transponders with beams targeting both the Nordic region and all of Europe.

It was moved to 31.5°E (0°00′N 31°30′E / 0°N 31.5°E / 0; 31.5) and renamed Astra 5A on 29 April 2008. The Astra 5A satellite mission ended on 16 January 2009 due to an abnormal condition with the spacecraft.[6]

Sirius Satellite Radio[edit]

The Sirius satellites are not the satellites used for the American Sirius Satellite Radio service, whose satellites are named Radiosat 1–4 due to being launched after the Sirius fleet of satellites.

References[edit]

  1. ^ Sirius 3 at 51.2°E, Lyngsat, retrieved 24 November 2012 
  2. ^ "Astra 2A ready for commercial operations at 28.2° east. Astra 1D to be relocated to 19.2° East" (Press release). SES Astra. 15 January 1998. 
  3. ^ "ILS Proton to Launch SES' Sirius 4". ILS. November 9, 2007. 
  4. ^ "Sirius-4 Specifications". Khrunichev. 
  5. ^ "SES SIRIUS BECOMES SES ASTRA" (Press release). SES Astra. June 22, 2010. Retrieved January 26, 2012 . 
  6. ^ "SES ASTRA Announces End Of ASTRA 5A Spacecraft Mission" (Press release). SES Astra. January 16, 2009. Retrieved January 26, 2012 . 

External links[edit]