The satellite will feature a new generation of digital signal processor and a 12-metre aperture antenna reflector and is scheduled for completion in early 2012.
It will supplement the existing Inmarsat-4 satellites and provide additional capacity to the Broadband Global Area Network (BGAN) services over Europe, the Middle East and Africa. Inmarsat will be able to use a new allocation of L-Band radio spectrum across these regions.
Alphasat I-XL will have a launchmass of 6,000kg, an electrical power of 12kW and a design lifetime of 15 years. Inmarsat expects its investment will be in the region of "260 million (US$386 million), excluding insurance.
Much of the new satellite will be developed and built by Astrium in the UK. It is supported by ESA and the British National Space Centre (BNSC), with financial support for the public/private finance bid from the South East England Development Agency, the East of England Development Agency and the London Development Agency.