In May 1997, Hughes Space and Communications International, Inc. received a contract
for one HS-376HP high-power satellite, ground station
equipment and support services from Nordiska Satellitaktiebolaget (NSAB). NSAB is a joint
venture of Swedish Space Corporation, Tele Danmark A/S and Teracom AB.
The new satellite, Sirius 3, provides direct-to-home television services to the
Scandinavian region. Hughes upgraded NSAB's satellite control center at Esrange, Kiruna,
and provided training to the satellite controllers. Sirius 3 was successfully launched on
an Ariane-44L H10-3 on October 5, 1998.
The satellite was built at the Integrated Satellite Factory of in El Segundo, Calif.
Since the launch of the first HS-376 in 1980, the
company 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 Sirius 3 satellite will also utilize a
liquid bipropellant system on-station for greater stationkeeping and attitude control
efficiency.
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.
The Sirius 3 antenna has shaped surface octagonal reflectors of approximately 2 meters
diameter, with single offset feeds. This antenna has three surfaces: one for horizontally
polarized signals, one for vertically polarized signals, and one for on-station tracking
and command.
Sirius 3 carries 15 Ku-band transponders powered by 44 watt traveling-wave tube
amplifiers (TWTAs). The spacecraft uses gallium arsenide solar cells to generate a minimum
of 1400 watts of spacecraft power at end of life and will rely on nickel-hydrogen
batteries for power through eclipses. Planned service life is 12 years.
Sirius 3 is used primarily for direct-to-home and cable television services as well as
data distribution in Scandinavia and neighboring countries, but is also capable of
providing television distribution and high-speed internet data to Greenland. Sirius 3 was
designed to be co-located at 5 degrees East but may be operated from other geostationary
longitudes as well. The Ku-band effective isotropic radiated power (EIRP) is minimum 54 dBW in the primary zone.
The satellite was retired in 2015 and was moved into a graveyard orbit above the geostationary belt.
.png)
