ESA’s science program budget will average 420 million euros ($492 million) per year between 2006 and 2010 following an agreement by government ministers to give the program an annual inflation adjustment of 2.5 percent.

Allowing the budget of the agency’s showcase program to reflect inflation may not sound like much, but it has long been the case that space science — the least controversial of ESA’s missions — is the most hotly contested budget line when ESA ministers meet every three years or so.

“The space science budget for a number of years has seen a degradation that has not permitted it even to cover inflation,” said Dutch Economics Minister and ESA Ministerial Council Chairman Laurens-Jan Brinkhorst. “Even a week ago I would not have believed we would achieve a 2.5-percent increase per year.”

Unlike most ESA programs, the budget for science is mandatory for the governments that participate in ESA. Each member nation’s contribution level is based on its gross domestic product. The spending is usually set for five years, and it is this commitment that causes governments to examine science spending more closely than any other program.

ESA’s science budget was set to rise by about 1.75 percent in 2006 to reflect the agency’s two new members, Greece and Luxembourg, whose contributions start next year.

ESA Science Director David Southwood earlier this year sketched out a long-term program called Cosmic Vision 2025 that required an increase in buying power. That roadmap now will need to be revised.

What is more, Southwood said limiting science to only an inflation increase through 2010 likely will force a cutback in missions already agreed to by the agency, but whose development has not yet begun.