LE BOURGET, France — The German government is willing to reconsider its position on whether the private sector is able to take over full financial responsibility for future civil German radar satellites in light of the slower-than-expected radar imagery revenue, the head of Germany’s space agency said.

Johann-Dietrich Woerner, executive chairman of the German Aerospace Center, DLR, said that while Germany is still pushing industry to assume an increasing share of the risk of building Earth observation satellites, it may be too soon to insist that industry go it alone.

“A full private investment in the next-generation satellite, TerreSAR-X 2, was what we had said we wanted,” Woerner said here June 23 during the Paris air show. “This was the basic idea, but we are now discussing whether this is feasible.”

TerreSAR-X was launched in June 2007 at a cost of some 185 million euros, or $260 million at current exchange rates, including launch charges. The German division of a company called Astrium Geo-Information Services paid 20 percent of that sum in return for exclusive rights to commercialize the radar data. DLR paid the remaining 80 percent.

A twin satellite, called TanDEM-X, was launched in June 2010. Its 165 million euros in cost was paid 75 percent by DLR and 25 percent by Astrium Geo-Information Services.

Both satellites are healthy in orbit and delivering imagery with a ground resolution of between 1 meter and 16 meters, depending on the desired observation mode and swath width. Since late 2010, they have been moved to within 350 meters of each other to operate in tandem to produce a stereo map of the Earth’s entire land mass.

Since the launch of TerreSAR-X, Astrium Geo-Information Services, which is part of Astrium Services and a subsidiary of Europe’s EADS aerospace conglomerate, has been informed by the French government that future French Spot optical Earth observation satellites will be the sole responsibility of the private sector.

Astrium Services is now spending around 300 million euros to build and launch the Spot 6 and Spot 7 satellites, which will succeed the larger Spot 5 satellite that is now in orbit and well past its contracted retirement date.

While Astrium Services is one of EADS’s most profitable businesses, the market for Earth observation imagery, and particularly radar data, has not grown as fast as expected.

Eric Beranger, chief executive of Astrium Services, said many governments — which remain the majority market for Earth observation data of all kinds — have reduced their budget for Earth observation data as part of broader spending cutbacks.

“This is mainly driven by short-term constraints and is not entirely unexpected,” Beranger said. He said that to make radar data more easily usable by government agencies more accustomed to optical data, Astrium Geo-Information Services is introducing what it calls “Color-SAR,” which he said is more appealing than conventional radar images, “which are mainly shown in shades of gray.”

The French government is financing the launch of two high-resolution Pleiades optical Earth observation satellites, each with a 70-centimeter imager, for commercial, civil government and military use. The first is set for launch on the second Europeanized version of Russia’s Soyuz rocket, a launch that has been tentatively scheduled for mid-December.

Astrium Geo-Information Services will have access to Pleiades data, but Beranger said neither the French nor any other government has committed to any purchases of Spot 6 and Spot 7 data. Astrium officials have said the French government’s decision not to take part in the satellites’ financing means French government agencies will be paying a lot more per Spot image than they have paid in the past.

Woerner said Germany accepts that the commercial business of selling radar data has been far slower than predicted when TerreSAR-X and TanDEM-X were launched.

“Our thinking was that fully recurrent satellites after TanDEM-X, which was the subject of a private-public partnership, should be paid for entirely by industry,” Woerner said. “But now we see that seems to be not so easy. The prices for which the images can be sold are not as high as what was expected. In addition, in some countries you have open access to data, which makes the commercial business a little tricky.”

Woerner did not disclose how far Germany would go in helping industry with the purchase of a successor to TerreSAR-X, a decision that must be made within the next year if Germany wants to avoid a gap in data flow in the event TerreSAR-X fails soon after its contracted five-year service life.

“It is a priority for us that we have continuity in X-band radar,” Woerner said. “But we still expect industry to keep its word” about increasing the share of program risk it takes in future systems.

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