Thor 2 [Boeing BSS]
Hughes Space and Communications International, Inc., under contract to Telenor of Oslo, Norway, provided powerful satellites to deliver direct-to-home television programming to Scandinavia and northern Europe.
In November 1995, Hughes was awarded the contract for Thor 2, a high-powered version of Hughes' spin-stabilized HS-376 model. Thor 2 was successfully launched in May 1997. That same month, Telenor announced the award of a follow-on contract to Hughes for a second high-powered HS-376HP satellite, Thor 3, which was successfully launched in June 1998.
Both contracts required Hughes to provide the spacecraft, launch services on a McDonnell Douglas Delta-7925 rocket, earth station upgrades at various sites, including the main site in Nittedal, Norway, and training. The satellites are built at the Integrated Satellite Factory of Hughes Space and Communications Company.
Since the launch of the first HS-376 in 1980, Hughes has continued to enhance and improve the design of this spin-stabilized satellite. Improvements in propulsion and power extend the life and increase the power capability in order to match heightened customer requirements. Through the use of gallium arsenide solar cells, today's high-power HS-376HP model features a 50% increase in power over its predecessor.
The HS-376HP has two telescoping cylindrical solar panels and antennas that fold for compactness during launch. The basic bus accommodates a wide range of customized payloads, and the satellite can be boosted by any of the world's major launch vehicles.
Thor 2 has 15 active Ku-band transponders (with three spares), powered by 40 watt
traveling-wave tube amplifiers (TWTAs). Thor
3 has 14 active Ku-band transponders powered by 47 watt TWTAs. Both spacecraft will use gallium arsenide solar cells to generate 1400 Watts of spacecraft power at end of life and will rely on nickel-hydrogen batteries for power through eclipses. The Thor spacecraft are each designed to operate for more than 11 years.
Telenor's three-satellite fleet will deliver television and telephony/data services to Scandinavia and Northern Europe, with western offshore beams to the Faroes, Iceland, and Greenland. Thor 2 and Thor 3 will be collocated at Telenor's Nordic Hot-Bird position at 1° West longitude. Thor 2 covers five zones stretching from Scandinavia across the north Atlantic to Greenland, with the primary zone comprising Norway, Denmark, Sweden, Finland, and the Baltic states. The Ku-band effective isotropic radiated power (EIRP) is 52 dBW in the primary zone. Thor 3 will cover three zones stretching from Scandinavia across the north Atlantic to Greenland and into eastern Europe. The EIRP for Thor 3 is 50 dBW.
The Thor antennas have shaped surface octagonal reflectors of approximately 2 meters diameter, with single offset feeds. These antennas have three surfaces: one for horizontally polarized signals, one for vertically polarized signals, and one for on-station tracking and command. Both spacecraft will use a bipropellant propulsion system for greater stationkeeping and attitude control efficiency.
Thor 2 was retired to a graveyard orbit in January 2013.
|Type / Application:||Communication|
|Equipment:||15 (+3) Ku-band transponders (#2); 14 Ku-band transponders (#3)|
|Power:||Solar cells (body mounted and drop-skirt), batteries|
|Mass:||1467 kg (#2), 1451 kg (#3), (853 kg BOL)|
|Thor 2||1997-025A||21.05.1997||CC LC-17A||Delta-7925|
|Thor 3||1998-035A||09.06.1998||CC LC-17A||Delta-7925|