France will no longer be the sole nation legally responsible for launches occurring from Europe’s Guiana Space Center, which is on French territory, according to an agreement reached between France, Russia and the European Space Agency (ESA).

Under the new regime, France will continue to assume full liability for launches of the heavy-lift Ariane 5 rocket. But France and Russia will share, in equal measure, legal liability for launches of Russia’s Soyuz rocket from the French Guiana site when they begin in 2008-2009.

For launches of ESA’s smaller Vega rocket, France will take a one-third share of legal liability, with the remaining two-thirds to be divided among the ESA member nations participating in Vega.

The reshuffling of legal liability in the event a launch causes injury or property damage in another nation was part of a package of decisions made Dec. 5-6 in Berlin at a conference of ESA government ministers.

Europe’s spaceport requires the launch-services provider — in this case the Evry, France-based Arianespace consortium — to take out its own insurance to cover damage or injury resulting from a launch. Arianespace is responsible for the first 60 million euros ($71 million) in damages. Any settlement for damages over that amount is guaranteed by the state that is responsible for the launch.

France has assumed this responsibility on its own even though it is not the sole “launching state” according to United Nations definition of the term. The U.N.’s 1972 Convention on International Liability for Damage Caused by Space Objects, which has been ratified by the world’s principal spacefaring nations, sets four definitions of a “launching state,” which are: the nation on whose territory the spaceport is located, the nation that conducts the launch, the nation that owns the launch site and the nation that procures the launch.

ESA is part-owner of the Guiana Space Center facility but under the terms of an agreement between ESA and France dating from the 1970s, “France agreed to cover the total liability, if any,” according to Giovanni Carra, head of the launcher industry relations office at ESA.

Carra said in a Dec. 15 interview that exactly who would face a demand for compensation in the event a rocket launched from the Guiana Space Center veered off course and slammed into, say, a city in Venezuela would depend on how the ensuing lawsuits were structured, and how the launch-procurement contract was worded.

But under a strict interpretation of the U.N. convention, he said, the nation in which a satellite owner is located also could find itself on the trail of liability in the event of a major launch-related disaster.

While France was the principal backer of the decision to operate Russia’s Soyuz launch vehicle from the Guiana spaceport, the launches will be conducted by Russian personnel and the Soyuz installation is being financed through ESA. Under a series of bilateral agreements between France, ESA and Russia, it was agreed that France and Russia would divide international liability for Soyuz launches once the 60-million-euro threshold has been reached.

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