PARIS — European Space Agency (ESA) governments have agreed to invest in advanced telecommunications satellite technologies to improve the competitiveness of European satellite prime contractors by offering higher power, greater room for antennas on a satellite platform, and better heat dissipation, ESA officials said.
The Alphabus Extension program, being managed by ESA’s Telecommunications and Integrated Applications Directorate, follows on from work done on the original Alphabus satellite platform, whose first model is scheduled for launch in 2012. This satellite, to be operated at 25 degrees east in geostationary orbit, is being used by Inmarsat of London for Inmarsat’s mobile communications services in L-band.
In addition to its principal Inmarsat mission, the satellite includes several technology demonstration payloads for ESA. The program was financed by ESA and the French space agency, CNES, with European prime contractors Thales Alenia Space and Astrium Satellites, in addition to Inmarsat, which is paying for the launch and insurance of the satellite, called Inmarsat-XL.
ESA estimates that this first Alphasat has cost 598 million euros ($813 million), of which ESA’s share is 230 million euros. The European Investment Bank and the European Commission have joined forces to provide up to 225 million euros as part of their Risk-Sharing Financial Facility.
Satellite prime contractors’ thinking about Alphasat and its Alphabus platform has evolved since the program was proposed a decade ago. Then, European satellite builders saw the increasing weight and power of spacecraft offered by Boeing, Space Systems/Loral and Lockheed Martin and thought the U.S. competitors were making advances Europeans needed to match.
Since then, the number of commercial satellites weighing more than 6,500 kilograms has not increased to the extent expected, in part because satellite owners want to maintain two launch options.
In recent years, the two options most consistently have been the International Launch Services (ILS) Proton rocket and Europe’s Ariane 5 ECA. Proton’s capability is edging up and is now around 6,600 kilograms, which is about the same mass that an Ariane 5 ECA can carry and still expect to fill the remaining Ariane 5 space with a second commercial customer.
Arianespace Chief Executive Jean-Yves Le Gall, whose company commercializes Ariane 5 rockets, openly questioned in January whether massive new capacity for Ariane 5 was needed given the lack of heavy satellites. Others in the industry say satellite builders are waiting for Arianespace and ILS, or some other provider, to offer a cost-effective launch for satellites weighing around 7,000 kilograms before designing the satellites.
ESA’s first Alphasat for Inmarsat, for example, is not expected to weigh much more than 6,200 kilograms.
But while Alphabus is not growing much in mass, ESA wants to allow it to grow in other areas, especially on-board power, to keep up with the competition.
Magali Vaissiere, ESA’s director of telecommunications, said Jan. 28 that the Alphabus Extension program, for which ESA has provided an initial 37.6 million euros in funding, is targeting capabilities that the market appears to want.
Under the new program, Alphabus will feature:
- Up to 22 kilowatts of power to the payload, compared with 18 kilowatts for the current Alphabus design.
- Thermal rejection capability of up to 19 kilowatts, compared with 11.5 kilowatts for the original Alphabus. Dealing with the heat generated by high-powered satellites, through deployable radiators or other means, is a core feature of ESA’s research.
- Electronics payloads weighing up to 2,000 kilograms, versus 1,250 kilograms for an 18-kilowatt Alphabus.
- Up to 230 transponders versus 190 transponders.
- Up to 12 antennas. No change from the original Alphabus configuration.
The Alphabus, ESA said, is being designed so that, when folded for launch, it can fit inside a Proton rocket’s 4-meter-diameter fairing.
