Thor (satellite)

Marcopolo redirects here. For the explorer, see Marco Polo. For any other, please see Marco Polo (disambiguation)

Thor (previously known as Marcopolo) is a family of satellites designed, launched and tested by Hughes Space and Communications (now part of Boeing Satellite Systems) for British Satellite Broadcasting (BSB), and were used for Britain's Direct Broadcast Service. Thor is owned by Telenor.^[1] Marcopolo 1 launched on 27 August 1989 on the 187th launch of a Delta rocket, and Marcopolo 2 launched on 17 August 1990, on a Delta II rocket.^[2] Marcopolo I had the Hughes designation HS376.^[3]

Although the satellites performed as designed, BSB^[4] merged with Sky Television to form British Sky Broadcasting and the BSB satellites were sold off and renamed. This also resulted in the obsoletion of the Squarial satellite-reception antenna, which was designed to operate with Thor 1 only.

Marcopolo 1 (Sirius 1/Sirius W)

Sirius W, originally Sirius 1, was launched on 27 August 1989. It was Hughes Space and Communications's first satellite. Marcopolo 1 was sold in December 1993 to Nordic 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 5 K_u band transponders.

Marcopolo 2 (Thor 1)

Marcopolo 2 was launched on 18 August 1990. It had 5 K_u band transponders. It was sold in July 1992 to Telenor of Norway 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 toward Scandinavia. Marcopolo 2 was sent up to the junk orbit in early January 2003.

Thor 2

Thor 2 was launched on 21 May 1997, and was retired in 2008 although it is still in inclined geostationary orbit. It weighs 1467 kg, and has 15 K_u band transponders, with 3 spares, powered by 40-watt traveling-wave tube amplifiers (TWTAs).

Thor 3

Thor 3 (the "3" is officially "III") was launched on 9 June 1998, and it was located at 0.8°W. It had 14 active K_u band transponders powered by 47-watt traveling-wave tube amplifiers (TWTAs). The satellite was targeted on Scandinavia, Eastern Europe, and parts of Central Europe. Thor3 is currently still in operation and is flying in inclined geostationary orbit but has been pointed towards the middle east. Thor 3 was replaced by Thor 6, in June 2010.

Intelsat 10-02 (Thor 4)

Intelsat 10-02 was launched on 16 June 2004, located at 1°W, and was beamed toward Central Europe and the Middle East.

Thor 5

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 K_u band transponders.

Thor 6

Thor 6 was successfully launched^[5] from the Guiana Spaceport on 29 October 2009. 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 K_u band transponders. It provides direct-to-home television broadcasting services from the orbital location 0.8°W. It replaced Thor 3.^[6]

Specifications^[7]

• Prime contractor: Hughes
• Platform: HS-376
• Mass at launch: 1250 kg
• Mass in orbit: 660 kg
• Payload mass: 100 kg: transponders: 90 kg, antennas: 10 kg
• Diameter: 2.16 m
• Height: 2.7 m (7.2 m deployed)
• Stabilization: Spin stabilized
• DC power: BOL: 1024 W
• Design lifetime: 10 years
• Beacon: 12.494 or 12.495 GHz

References

1. ^ BSB History by Boeing
2. ^ "Boeing Launch Services Mission Record". Boeing. http://www.boeing.com/defense-space/space/bls/missions/index.html. 
3. ^ [1] NASM's Herbert Stephen Desind Collection,p. 36
4. ^ BSB1
5. ^ Telenor Satellite Broadcasting
6. ^ Telenor Satellite Broadcasting
7. ^ BSB Specs