French defense authorities would be willing to take up to a 50-percent stake in a Ka-band satellite to be used for low-security broadband communications links with deployed troops and unmanned aerial vehicles, according to the French arms-procurement agency, DGA.

The remaining share of the project would be reserved for other European defense forces or for civil/commercial use, according to the DGA.

Charles de Lauzun, DGA’s deputy for space, said defense authorities have concluded that such a satellite, dubbed Athena, could be linked with two-way ground terminals adapted for military applications costing no more than 2,000 euros ($2,400) apiece if purchased in batches of 4,000 units.

In a presentation here Sept. 21 during a briefing on government space programs’ relations to commercial markets, organized by industry-lobbying group Prospace, de Lauzun said DGA and the French space agency, CNES, have been canvassing other European governments to sound out support for Athena.

Athena was conceived when a CNES-originated idea for a Ka-band satellite for commercial use only, called Agora, failed to win any sizable support from the commercial satellite operators CNES had assumed would be willing to operate the Agora system.

Athena is the latest example of CNES and DGA taking advantage of the dual-use nature of space systems, and of the price declines caused by the rollout of commercial satellite and ground-system hardware —- in this case, Ka-band satellites and ground terminals.

CNES and DGA since 2003 have developed a closer relationship as CNES seeks to position itself as an indispensable participant in Europe’s long-promised, but still emerging, military space effort.

For example, CNES is co-managing with DGA a two-satellite radar reconnaissance demonstrator system, called Elint, despite the fact that Elint will use a CNES-developed satellite platform that already has proved itself in orbit and has thus moved out from under CNES’s normal research and development umbrella.

CNES had foreseen Agora as a system to give French rural communities access to high-speed Internet connections. But a commercial satellite operator willing to take charge of Agora was never found.

DGA meanwhile has been searching for a way to provide high-speed data and video access to French forces deployed in South America, Africa, Afghanistan and elsewhere.

In addition, the recent priority French defense officials have given to unmanned aerial vehicles — which are heavy users of bandwidth — has stimulated a search for solutions that would not gobble up capacity on France’s current and future dedicated Syracuse military communications satellites.

DGA has determined that much of the demand for future bandwidth by French defense forces will not require heavily encrypted, jam-proof and radiation-hardened platforms such as the future Syracuse 3 satellites entering service in the coming months.

According to de Lauzun, leasing capacity aboard commercial satellites operated by Eutelsat S.A. of Paris or Intelsat Ltd. of Washington would cost much more than a dedicated Athena satellite — assuming one or more partners could be found. DGA estimates that commercial Ku- and C-band capacity would cost three to five times more than Athena’s Ka-band, on a megabit-per-second basis.

DGA has evaluated two-way Ka-band terminals available from Thomson of France and EMS Technologies of Canada and determined that they would need only slight modification from the commercial Ka-band gear now in development. The 1-meter-diameter Athena terminal antenna, providing 2 megabits per second of throughput, would be deployed in batches of 1,000 per theater of operations, according to DGA.

With France and Europe set to begin operating Russia’s Soyuz rocket from Europe’s equatorial Guiana Space Center in 2008, a low-cost launch option for French and European defense forces has suddenly become available.

The Europe-launched version of Soyuz will be able to place a 3,000-kilogram satellite into geostationary transfer orbit, the destination of most communications spacecraft. The price currently forecast for these launches is $40 million.

Including the Soyuz launch and insurance, an Athena satellite could be placed into operations for about 155 million euros, de Lauzun said. The price would rise to around 175 million euros if other nations’ demands forced Athena’s payload to add 20 transponders beyond those to be reserved for the French Defense Ministry, he said.

Peter B. de Selding was the Paris bureau chief for SpaceNews.