PARIS — The 27-nation European Union and individual European nations that are not taking part in the international space station will be able to place experiments on the orbital complex for a three-year trial period that ultimately could provide a fresh revenue source for the project, European Space Agency (ESA) officials said Oct. 21.

The new policy, disclosed by ESA Director-General Jean-Jacques Dordain during a meeting in Brussels, Belgium, of European ministers to discuss space exploration policy, has been approved by the ESA governments now financing Europe’s space station program and by NASA and the other station partners, Dordain said.

Only 10 of ESA’s 18 member states currently contribute to the project, led by Germany, with about 38 percent of Europe’s share, followed by France, with 27.6 percent, and Italy, with 18.9 percent.

Dordain said opening the station to nonparticipating ESA and European Union nations would be permitted through 2013 and was “good news” as Europe seeks to reposition the space station as a springboard and testing ground for future space exploration efforts.

Several nations taking part in the second International Conference on Space Exploration voiced support for extending the station’s life at least until 2020, a NASA proposal that other station partners — Canada, Russia and Japan — have accepted but Europe is still weighing.

The problem in Europe is financing. Germany has committed to paying its 38 percent share of Europe’s station operating costs between 2011 and 2020, an investment that Germany estimates will total about 3.8 billion euros ($5.3 billion).

France has not yet committed to the 10-year financial effort. Unlike many of her colleagues making statements at the exploration conference Oct. 21, French Research Minister Valerie Pecresse made no mention of the space station as a future exploration platform, and avoided any reference to the topic of extending the station’s operational life.

Simonetta di Pippo, ESA’s director of human spaceflight, said the agency still expects to win its member states’ formal support for the station extension in December. In an Oct. 21 interview, di Pippo said the exact cost of the 10-year effort will depend on which options ESA members agree to adopt. Among other possibilities, she said, ESA could elect to pay NASA in cash for Europe’s use of the station’s common resources, or it could develop further unmanned cargo carriers to offset the cash obligation.

Di Pippo said the European Commission, which is the executive arm of the European Union, has recently taken a seat at meetings of ESA’s space station program board. In addition, the commission has agreed to permit its research funds to be used for space station experiments.

In 2014, the commission’s next seven-year financial package is scheduled to be approved. It is in this document that a more formal relationship in station participation should be detailed, including what financial resources from the commission might be added to ESA’s to finance Europe’s station use, di Pippo said.

“I see a lot of very good intentions,” di Pippo said. “This three-year pilot phase is there to show how this process might work, how it could be put together.”

Several nations attending the Oct. 21 conference said they supported the international space station but that its operating costs needed to be reduced. Some of these nations also said bluntly that new station users sooner or later should be prepared to pay their way out of consideration for the investment made in building the orbital complex.

Di Pippo said reducing cost is one of the elements of the proposal ESA will make to its member states in December as it seeks endorsement of the extension of station operations to 2020.

ESA also is discussing with NASA alternatives for a common transport policy for the station after the U.S. space shuttle is retired in 2011. The conclusion of these talks, which di Pippo said would continue in Cape Canaveral, Fla., the week of Oct. 25, will help ESA determine whether it should develop an enhanced version of its Automated Transfer Vehicle cargo freighter. The proposals involve enhancing the vehicle’s cargo-carrying capacity and making it capable of returning experiments to Earth instead of being burned up on re-entry into the atmosphere.

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