BERGEN, Norway — The European Space Agency (ESA) and the European Parliament have endorsed the idea of free and open access to data from Europe’s future generation of Sentinel Earth observation satellites, with the possible exception of imagery with a ground resolution sharper than 10 meters, European government officials said.

The Global Monitoring for Environment and Security (GMES) project, in which three types of Sentinel satellites play a key role, ultimately will be owned by the 27-nation European Union, with its data policy to be set by European Union governments and the European Commission.

But with ESA already adopting the policy for the satellites it controls and the recent European Parliament endorsement of the free-and-open scheme, officials here said they were confident that most GMES data would be open to just about anyone in the world with access to a broadband Internet connection.

ESA Earth Observation Director Volker Liebig said the agency has already thrown open access to its Earth observation satellites, eliminating the need to wait for an announcement of opportunity, or AO, before submitting a request for data and awaiting approval.

“You don’t need to go through the AO anymore,” Liebig said. “Obviously we are restricted by our own data processing system, so you can’t order full-planet coverage and ask for delivery within five days.”

In its June 16 resolution on GMES, the European Parliament endorsed this view, concluding:

“There should be a full and open-access data policy for the Sentinels through a free-of-charge licensing and online access scheme, subject to security aspects.”

Gunther Kohlhammer, head of ESA’s Earth observation ground segment department, said June 29 satellites whose data are made part of the GMES portfolio but are not owned by ESA or the European Commission — so-called Third-Party Missions — may have more-restrictive data-distribution policies that GMES managers will have to respect.

In addition, Kohlhammer said the European Commission’s ongoing review of the security aspects of GMES could add new wrinkles to the overall open-access policy, particularly with respect to high-resolution imagery.

“Ten meters is the range where operators offer data free and open and that is what we are talking about now — imagery with a ground resolution of 10 meters and greater will be subject to the free-and-open policy. The Sentinels, as defined, adopt this 10-meter limit. But the ‘S’ in GMES could force a review,” he said of security-related concerns that could still surface.

Satellite data access has been a hotly debated topic for years. Some argue that the private sector will not fully develop the sector if the imagery cannot be put behind a firewall and prepared for sale. Others, pointing to the U.S. GPS navigation system, say offering the data free of charge at the source, and having the private sector focus on value-added services, is the best way to stimulate the use of the data.

Access to U.S. Landsat data used to be subject to fees. Since it has been available free of charge, downloads of Landsat data have increased “exponentially,” said Timothy Stryker, director of policy, plans and analysis for land remote sensing at the U.S. Geological Survey.

The August 2008 decision to make the archives of Landsat data available on the web without charge has resulted in a 60-fold increase in the number of scenes downloaded per day, with U.S. and Chinese users being the most frequent of the 186 nations that have taken advantage of the service, Stryker said here June 28.

“In our best year of sales, 2001, we distributed an average of 53 scenes per day,” Stryker said. “The average has been increasing steadily and is around 3,125 scenes per day of web-enabled data. We passed the million-scene mark in August 2009 and passed 2 million scenes on March 13.”

In addition to the sheer numbers, Stryker said more users are now asking for multiyear images of the same area for land-use and environmental-change studies.

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