PARIS — Commercial Earth observation was all but invented in France, yet companies here that pioneered the high-resolution optical imagery market a decade ago have been edged out in recent years by tough competition in the U.S.

That could change, however, with the planned launch of France’s first Pleiades high-resolution Earth-observation satellite this month, one of two next-generation optical-imaging spacecraft designed to serve military and civil users while reserving capacity for commercial customers.

Nearly 10 years in the making, the €760 million ($1 billion) Pleiades program started in October 2003 with a €314 million fixed-price contract awarded to EADS-Astrium by the French space agency CNES, with Thales Alenia Space of France and Italy providing the principal optical instrument.

Financed almost entirely by the French government, both satellites were designed to launch atop Europeanized Soyuz rockets—the first in mid-2008, followed by the second in 2009.

But the debut of the rocket from Europe’s Kourou, French Guiana, spaceport was postponed repeatedly, forcing lengthy delays in the Pleiades launch and depriving Astrium of anticipated revenue.

Meanwhile on the opposite side of the Atlantic, the U.S. Defense Department in 2010 awarded a 10-year, $7.3 billion contract to two Astrium competitors in the U.S.—Dulles, Va.-based GeoEye and Longmont, Colo.-based DigitalGlobe—dramatically altering the landscape for commercial Earth-observation services in the global market.

Both Pleiades satellites are to be launched to a polar orbit at 694 km in altitude with 180 deg. between them in order to maximize the revisit time for any given area of the Earth’s surface. The second satellite is scheduled for launch in spring 2013.

The French Ministry of Defense, through annual contributions to CNES, is paying 90% of the Pleiades mission. Pleiades is set to launch Dec. 16 from French Guiana, along with four Elisa radar eavesdropping satellites developed for the French procurement agency DGA and a Chilean Earth-observation satellite. All six spacecraft are built by Astrium.