Alphasat
Alphasat is the most sophisticated commercial communications satellite ever built, providing in-orbit validation of the Alphabus platform, flight opportunities for four technology demonstration payloads and support for new payload technologies. It was engineered and built by EADS-Astrium through a public–private partnership (PPP) between ESA and Inmarsat.
Alphasat’s advanced geomobile communications payload provides access to the extended L-band spectrum and enables a wide range of high data rate services for aeronautical, land and maritime users across Europe, Asia, Africa and the Middle East. Alphasat is expected to handle more than 750 mobile communication channels in this band, improving signal quality particularly for satphone users.
Its innovative payload includes advanced digital integrated processors developed by EADS-Astrium, which allow unprecedented flexible allocation of capacity in L-band, through digital channellisation and beamforming.
Alphasat has been designed for 15 years of in-orbit lifetime. Launch and Early Orbit Phase operations will be conducted from the EADS-Astrium spacecraft control centre in Toulouse.
The Alphabus platform
Alphasat is based on Alphabus, the new European high power telecom platform. With Alphabus, European industry has significantly extended its telecom satellite range beyond the capabilities of previous platforms. It is available on the commercial market in an extended version to accommodate missions with up to 22 kW of payload power and up to 1400kg payload mass.
Technology Demonstration Payload
In addition to the large and powerful communications payload, Alphasat carries ‘hosted’ payloads. The 4 technology demonstrators were developed through ESA’s ARTES programme or provided by the DLR German Space Center, in order to qualify new technologies in space. Their total mass is about 140 kg and they require a total power of 600 W.
They include:
• Optical communications and Ka-band downlink - an Advanced Laser Communication Terminal to demonstrate GEO to LEO communication links at 1064nm (supplied as customer furnished item by DLR)
• Q/V-band communication and propagation - a Q-V Band communications experiment to assess the feasibility of these bands for future commercial applications
• Startracker - an Advanced Star Tracker with active pixel detector
• Environmental testing and radiation sensor - an Environment effects facility to monitor the GEO radiation environment and its effects on electronic components and sensors
The partnership
Alphasat has been built by EADS-Astrium as prime contractor through a public-private partnership (PPP) between ESA and Inmarsat. The Alphabus satellite platform, used by Alphasat, was developed by EADS-Astrium and TAS (Thales Alenia Space) under a joint contract with ESA and France’s CNES space agency.
The market
The Alphabus platform was developed in response to the worldwide market demand for larger telecommunication payloads aimed at direct-to-home TV broadcasting, digital audio broadcasting, broadband access and mobile services. Alphabus targets the upper part of the world market segment (above 6 tonnes). It completes the range of available European buses to cover the full range of the world GEO telecom market.
The launch
Alphasat was successfully launched by Ariane 5 on 25th July 2013 from the European Spaceport at Kourou, French Guiana.