LONDON — Backers of Europe’s EDRS optical data-relay system suggested that while the program was first sold as a way of speeding delivery of civilian Earth observation satellite data to users, its bigger future market is in handling military data from unmanned aerial vehicles (UAVs).

European Data Relay System (EDRS) managers at Astrium Services and laser terminal builder Tesat-Spacecom GmbH said they expect to accelerate trials of the service, now limited to a laser terminal on a Falcon jet operated by the German space agency, DLR, to tests of an airborne laser optical terminal on a UAV starting in 2013.

A commercial airborne laser terminal would be ready by 2014, the year the first of two EDRS payloads is expected to be in orbit.

In presentations here to the Global Milsatcom conference organized by SMi Group, Astrium Services and Tesat said they are counting on the European Space Agency (ESA) to enlarge the current EDRS program by agreeing to build a third EDRS node in geostationary orbit, likely as a hosted payload on a commercial telecommunications satellite.

One U.S. industry official said here that he could not understand why EDRS terminals were not being installed systematically on U.S. military UAVs given the advantages of optical communications links over Ka-band, X-band and other radio frequency communications.

The reason, as one European industry official supporting EDRS said, is that while the system has almost proved itself technically, it is not yet in orbit and cannot yet provide global coverage. With a third node in orbit, this official said, global coverage could be assured and the military market should embrace EDRS.

EDRS is an ESA program constructed as a 15-year public-private partnership with Astrium Services. ESA has contributed 275 million euros ($358 million) to the project, with Astrium paying the remaining share, estimated at less than $100 million.

The first EDRS payload is being prepared for launch in 2014 aboard a commercial telecommunications satellite owned by satellite fleet operator Eutelsat of Paris. Eutelsat 9B, under construction by Astrium Satellites, will operate at 9 degrees east in geostationary orbit.

The second EDRS laser terminal will be mounted on a dedicated EDRS satellite to be launched in 2015 and operated at 31 degrees east in a slot reserved by Avanti Communications of London. Avanti will be placing its own commercial telecommunications payload on the satellite, which Avanti calls Hylas 3.

Backnang, Germany-based Tesat has been testing its laser communications terminals since 2007 as part of a U.S.-German joint program that used the U.S. Missile Defense Agency’s Near Field Infrared Experiment satellite and Germany’s TerraSAR-X radar Earth observation satellite to test inter-satellite communications and satellite-to-ground links using optical signals to send data at rates of 5.6 gigabits per second.

ESA’s Alphasat project, a partnership with mobile satellite services provider Inmarsat of London, carries a Tesat laser terminal as one of several technology demonstration experiments placed on the new Alphabus platform. Inmarsat has purchased the first Alphabus satellite and will use it to bolster its existing L-band mobile communications services. Alphasat is scheduled for launch in mid-2013.

Martin Agnew, head of EDRS service creation in Astrium Services’ government communications division, said Astrium and Tesat expect their partnership with General Atomics Aeronautical Systems of San Diego to result in placing a laser terminal on an airborne application starting in 2013 as well.

General Atomics’ Predator C Avenger UAV is one of several unmanned systems — others include the Northrop Grumman Global Hawk and its European variant, the EADS Cassidian Euro Hawk, and BAE Systems’ Taranis — that Agnew said are key potential EDRS platforms. Others include high-altitude communications platforms and manned cargo aircraft.

Optical laser communications require that the moving platform operate above the clouds or in clear weather. Fighter-jet-type maneuvers are ill-advised as the aerial platform must be tracked with a 500-meter-diameter laser footprint.

Matthias Motzigemba, director of laser products at Tesat, said laser links have multiple advantages over X- and Ka-band, both of which are used widely by the military. They are inherently jam-resistant and use less power than terminals using X- and Ka-band. The most logical military uses are for platforms that must offload a large amount of data in a short period of time.

The German government has been the biggest backer of EDRS, first investing in Tesat’s laser terminal and then investing heavily in ESA’s new telecommunications satellite platform, called Small-Geo, being built by OHB AG of Bremen, Germany.

ESA and German government officials say they plan to ask ESA governments for a second tranche of EDRS funding in 2014 to give the service a third terminal in space. Astrium Satellites officials have said that would give them enough time to sell the idea of a hosted payload to one of their future commercial customers — preferably one planning a satellite over North America.

EDRS is still grappling with the fact that the institution that had been identified as its anchor customer, the European Union, is having trouble securing a budget for the Earth observation satellites that are being fitted with EDRS-compatible laser terminals.

For now, four satellites — Sentinels 1A, 1B, 2A and 2B — are under construction with laser communications capabilities. The French Defense Ministry has not yet said whether its next-generation optical surveillance satellites will have optical terminals, and Germany has not confirmed that the second-generation SAR-Lupe radar reconnaissance constellation will have a laser communications capability.

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.