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Thor (previously known asMarcopolo) is a family ofsatellites designed, launched and tested byHughes Space and Communications (now part ofBoeing Satellite Systems) forBritish Satellite Broadcasting (BSB), and were used forBritain'sDirect Broadcast Service. Thor was owned byTelenor,[1] but the division was sold toSpace Norway in 2023.[2]
Marcopolo 1 launched on 27 August 1989 on the 187th launch of aDelta rocket, and Marcopolo 2 launched on 17 August 1990, on a Delta II rocket.[3] Both satellites were based on theHS-376 satellite bus.[4]
Although the satellites performed as designed, BSB[5] merged withSky Television to formBritish Sky Broadcasting and the BSB satellites were sold off and renamed. This also resulted in the obsoletion of theSquarial satellite-reception antenna, which was designed to operate with Thor 1 only.
Sirius W, previously known as Sirius 1, was launched on 27 August 1989. It wasHughes Space and Communications's first satellite. Marcopolo 1 was sold in December 1993 toNordic Satellite AB of Sweden and operated until 2000 as Sirius 1 at 5°E. It was then moved to 13°W, and renamed Sirius W. It had five Ku band transponders.
Marcopolo 2 was launched on 18 August 1990. It had five Ku band transponders. It was sold in July 1992 toTelenor ofNorway and renamed Thor 1. It was located at 0.8°W. It was switched off in January 2002, and in November of that year it was moved to 7.4°W and reactivated with digital test signals broadcasting towardScandinavia. Marcopolo 2 was sent up to thejunk orbit in early January 2003.
Thor 2 was launched on 21 May 1997, and retired in 2008 although it remained in an inclined geostationary orbit until January 2013 when it de-orbited to the graveyard orbit.[6] It weighs 1467 kg, and has 15 Ku band transponders, with three spares, powered by 40-watt traveling-wave tube amplifiers (TWTAs).
Thor 3 (the "3" is officially "III") was asatellite used byCanal Digital in the Nordic areas forDTH services. It launched on 9 June 1998 with an expected lifetime at 12 years, and was located at 0.8°W. It had 14 active Ku band transponders powered by 47-watt traveling-wave tube amplifiers (TWTAs). The satellite was targeted onScandinavia,Eastern Europe, and parts ofCentral Europe.[7] Thor 3 is no longer in operation and was moved to its graveyard orbit in 2019. Thor 3 was replaced by Thor 6 in June 2010.
Intelsat 10-02 was launched on 16 June 2004, located at 1°W, and was beamed towardCentral Europe and theMiddle East.[8]
Thor 5 was launched on 11 February 2008. It was first planned that the satellite would be called Thor 2R, but Telenor named it Thor 5. It has 24 active Ku band transponders.
Thor 6 built by Thales Alenia Space was launched from the Guiana Spaceport on 29 October 2009.[9] Telenor Satellite Broadcasting announced on 15 December that Thor 6 had completed all necessary in-orbit and ground-related testing and would commence commercial service in late December.
Thor 6 has 36 Ku band transponders. It provides direct-to-home television broadcasting services from the orbital location 0.8°W. It replaced Thor 3.[10]
Thor 7 has been built bySSL. It was successfully launched byArianespace fromKourou spaceport on 26 April 2015. It will mainly serve maritime customers and have a total capacity of 9 Gbit/s. It was launched in tandem with the Italian/FrenchSicral 2 defense satellite.