 |
| The EADS Astrium-built
satellites for Inmarsat’s new mobile communications Broadband
Global Area Network are larger and more powerful than any other
geomobile satellites (EADS
Astrium/C. Mériaux photo) |
TOULOUSE, Feb. 4/Satnews Daily/ — EADS
Astrium said on Thursday it has completed production and test of the
first Inmarsat-4 spacecraft, which it claims is the world’s most
sophisticated commercial communications satellite. The spacecraft will
leave the Toulouse facility on February 5 for shipment to Cape
Canaveral.
Scheduled for launch on March 10, 2005 aboard an Atlas V launch vehicle
from Cape Canaveral, Florida, the first giant Inmarsat-4 satellite will
be positioned in geostationary orbit at 65 degrees East longitude. It
will enable Inmarsat to address a wide area covering most of Europe,
Africa, the Middle East and Asia, as well as the Indian Ocean.
A second satellite is planned for launch in summer
2005 to cover South America, most of North America, the Atlantic Ocean
and part of the Pacific Ocean. A third satellite is also at an advanced
stage of production. All three satellites are identical and
interchangeable - their coverage is programmable and can be reconfigured
in orbit.
These satellites are based on EADS Astrium's Eurostar E3000 satellite
platform, three of which entered commercial service in 2004. All three
Inmarsat-4 satellites are equipped with electric propulsion system.
Their 45m long solar array generate 14 kW of electrical power at
beginning of life and the spacecraft weighs approximately 5,940 kg at
launch.
The main body is 7 meters high and the unfurlable
antenna reflector has a diameter of about 10 meters. EADS Astrium said
its facilities in the UK, Germany, Spain and France have contributed to
the design and manufacture of the highly innovative spacecraft and
provided most advanced technologies.
The spacecraft will provide continuity with existing Inmarsat systems
and offer additional capacity and performance. They will also provide
the new Broadband Global Area Network service over the major land masses
and a large part of the ocean surface. This will extend coverage of
third generation terrestrial mobile networks such as UMTS (3G) for
telephony, data and high speed Internet access to laptop and palm-sized
terminals. This will enable business travelers, disaster relief workers,
field based oil researchers, journalists, etc to operate a virtual
office anywhere in the satellite footprint, including on maritime or air
routes.
In order to support small terminals over the whole area with the high
signal strength required, each satellite can digitally form more than
200 spot beams. More power and spectrum can be allocated to certain
beams, further enhancing mission flexibility to cope with the
fluctuations in traffic. An on-board digital signal processor routes the
signals to the different beams, acting like a switchboard in the sky:
any signal uplink can be routed to any mobile downlink beam and vice
versa. Frequency agility and extensive frequency re-use across the beams
permit efficient utilisation of the available channels in the L-band
spectrum to provide increased capacity.
The satellites will link to gateways and directly to users equipped with
different types of ground terminal, ranging from hand-held to
transportable terminals with data rates of up to 1 Mbps. A typical user
terminal looking like a small laptop, will receive at 432 Kbps.
The Inmarsat-4 satellites also feature 19 wide beams and full global
coverage to provide continuity of existing Inmarsat services for
maritime, air and emergency services. A navigation package extends and
enhances the navigation signals already available on Inmarsat-3
satellites for the air traffic community.
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