Satellite communications provider, Inmarsat, has engaged European manufacturer Astrium, an EADS division, to build the Alphasat I-XL satellite, due for induction into its global coverage system by 2011.
Under a euro 260 million contract, Astrium, will develop an Inmarsat payload and integrate it with the first example of the European Space Agency''''s (ESA) Alphabus next-generation communications satellite platform.
The ESA-developed Alphabus will provide the basis for a new and very powerful generation of communications spacecraft. The first of the series, Alphasat I-XL, will feature a new-generation digital signal processor, which will flexibly manage communications traffic, with the help of a 12m-aperture reflector antenna.
It will have a mass of about 6,000kg at launch, an electrical power rating of 12kW and a design lifetime of 15 years.
Inmarsat will operate the spacecraft for a minimum of three years to support and expand the Broadband Global Area Network (BGAN) land-mobile and maritime services, and the related 432kbit/sec SwifBroadband for aviation, which are currently delivered by the company''''s fourth-generation satellites.
Compared with the Inmarsat-4s, the third and last of which is to be launched to cover the Pacific next year, the new Alphasat I-XL will be two times more sensitive and also transmit twice the amount of power, making possible smaller mobile terminals and antennas, higher data rates and lower communications costs for users.
"Alphasat will enable us to offer existing and future Inmarsat customers more capacity, better-quality communications and faster downloads," says Inmarsat chief executive Andrew Sukawaty.
Alphasat I-XL could also act as a "4.5G" stepping stone towards the fifth Inmarsat generation. Currently in the early conceptual phase, the fifth generation satellites will be four times more powerful than the Inmarsat-4, and would likely include Ku or S-band payloads alongside the company''''s traditional L-band capability.