European space scientists started the year by celebrating the history-making descent of their Huygens probe through the atmosphere of Titan and ended it by wondering how to fit future missions into a budget that will keep up with inflation, but no more, through 2010.

European Space Agency (ESA) Science Director David Southwood was referring to mission-related suspense when he referred to 2005 as "a nail-biting year. And now we're beginning to take delivery of [the results] of what we are doing."

The January success of the Huygens descent, part of the large U.S.-European Cassini-Huygens mission, continues to produce science data nearly a year later.

Jean-Pierre Lebreton, ESA's Huygens project manager, said the initial engineering feat of deploying the Huygens system and receiving the data now is yielding the stage to the data scientists wanted about Huygens' surface and atmosphere.

"We indeed had an engineering success and we are converting it into a scientific success," Lebreton said during a Nov. 30 presentation of early Huygens results. It will be several months before the full harvest of Huygens data is completed and at least that long as well before the findings of ESA's Mars Express orbiter come fully into view.

The U.S.-provided Marsis radar on Mars Express has begun to peer several kilometers beneath the surface. But it will not begin what is expected to be its most promising investigations of Mars until next spring.

Mars Express' mission is centered on the search for large water or water-ice deposits and evidence of current or past life. The satellite's high-resolution stereo camera already has collected a half-terabyte--500 gigabytes--of compressed raw data, which when treated is equivalent to 5 terabytes. Gerhard Neukum, the camera's principal investigator, said 25 percent of Mars' surface already has been mapped with a ground resolution of 20 meters or better.

ESA's Science Program Committee has extended Mars Express financing to permit operations through 2007. Agustin Chicarro, ESA's Mars Express project scientist, said the satellite is likely to stay healthy to permit operations at least through 2010--funding permitting--and perhaps longer.

Scientists are generally hesitant to talk about funding issues, even if budget limits are never far from their thoughts. On that score the news was generally good in 2005.

The Science Program Committee agreed to extend the Integral gamma-ray astronomy satellite's mission to December 2010, and also agreed to permit the XMM-Newton X-ray observatory to operate until March 2010. The satellites were launched in 2002 and 1999, respectively.

The sun-observing Soho satellite, launched in December 1995, originally designed for a two-year mission, is expected to continue in service until 2007, permitting it to complete operations during an entire solar-activity cycle of 11 years.

ESA's unusually failure-free record in science missions--the loss of the Cluster satellites in 1996 in a launch failure was compensated by a rebuild and later launch of the mission--was nearly blemished in 1998 when Soho managers lost contact with the satellite for a month. Ground teams including prime contractor EADS Astrium subsequently returned Soho to operations despite the loss of its gyroscopes.

The Venus Express satellite launched Nov. 9 continued the run of successful launches and early operations. It is expected to reach orbit around Venus in April.

European scientists say these missions are the fruit of investments made years--sometimes more than a decade--ago at a time when Europe's space science was growing. That has not been the case for several years. ESA government ministers agreed Dec. 6 to partially remedy the problem by permitting a 2.5-percent annual increase in the science budget between 2006 and 2010.

Some officials hope the budget adjustment will permit Europe's science program to slightly increase its buying power with respect to inflation. Others say it is equivalent to a flat budget.

Southwood said it is likely that one large ESA science mission now being planned will have to be delayed or canceled to permit the program to build its other missions and leave aside funds for unanticipated needs.

The Herschel and Planck astronomy satellites, which already are well over budget and a year behind schedule, are considered candidates for cancellation. They now are booked for a launch together on an Ariane 5 rocket the first half of 2008.

The Science Program Committee is likely to determine in 2006 which future mission will be sacrificed.