Alphasat [ESA]
Alphasat or Inmarsat-4A F4 (originally Alphasat I-XL or Inmarsat XL) is a joint ESA and Inmarsat communications satellite using the Alphabus proto-flight platform, achieving in-orbit validation of the ESA initiated platform through a commercial operator.
Alphasat features a new generation digital signal processor for the payload, and a 12-meter aperture antenna reflector. The spacecraft has a mass of 6649 kg at launch, an electrical power of 12 kW. Planned for launch in 2012, Alphasat has a design lifetime of 15 years.
Inmarsat flew an extended L-band payload, in parallel to and supporting its existing world-leading global mobile satellite services. This Inmarsat mission definition is based around multimedia mobile services already provided by the current Inmarsat-4 satellites through Broadband Global Area Network (GAN)
The satellite is positioned at 25 degrees east, with its coverage centred over Africa and providing additional coverage to Europe, the Middle-East and parts of Asia.
Implementation of this Geo-mobile application uses the Alphabus platform design in a configuration that requires a 90 degree change to the satellite flight orientation to improve accommodation of the feed/reflector configuration and allow the embarkation of a large deployable reflector. Both of these capabilities are offered as options in the Alphabus portfolio.
In addition, Alphasat embarks three ESA-provided technology demonstration payloads:
The Alphasat programme meets the diverse but mutually compatible goals of all the parties, such as the first flight and in-orbit verification of Alphabus and the implementation of an advanced L-band operational payload, which supplements the existing Inmarsat satellite constellation and offer the opportunity for new and advanced services.
The contract was signed in November 2007 with a launch targeted by 2013.
Nation: | International |
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Type / Application: | Communication |
Operator: | ESA, Inmarsat |
Contractors: | EADS Astrium, Thales Alenia Space |
Equipment: | L-band payload |
Configuration: | Alphabus |
Propulsion: | EAM, PPS-1350-G plasma thrusters |
Power: | 2 deployable solar arrays, batteries |
Lifetime: | 15 years |
Mass: | 6649 kg |
Orbit: | GEO |
Satellite | COSPAR | Date | LS | Launch Vehicle | Remarks | |
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Alphasat (Inmarsat-4A F4) | 2013-038A | 25.07.2013 | Ko ELA-3 | Ariane-5ECA | with Insat 3D |
Further ESA communications satellite missions:
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Further Inmarsat missions:
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