Space scientists in Europe are pleading with ministers to significantly boost the European Space Agency's (ESA's) science programme when they meet to decide its budget for the next five years. Without such an increase, researchers fear that high-profile missions may have to be abandoned.

“We are struggling to keep control of the budget,” says Marcello Coradini, coordinator of Solar System Missions at ESA headquarters in Paris. Costs of science missions in development are predicted to exceed available money by €300 million (US$350 million) to €400 million over the coming decade.

If money allocated by ESA's ministerial council, which meets in Berlin on 5–6 December, does not alleviate the pressure on the programme's finances, scientists say it may not be possible to cut back missions without undermining their scientific goals. And agency officials say they may be reluctant to absorb the costs — roughly equivalent to one year of spending — through delays, because that means no new missions can be started.

The situation has led to speculation that BepiColombo, a mission destined for a 2013 launch to Mercury, might be cancelled. “That is the big danger painted in the sky,” says Karl-Heinz Glassmeier, principal investigator on one of the instruments proposed for the spacecraft.

ESA scientists are concerned that BepiColombo may be cancelled. Credit: ESA

Nerves were set jangling about the project, which also involves the Japan Aerospace Exploration Agency, after it was postponed because the initial design was too heavy. That problem seems to have been solved, but officials say the estimated cost of the mission, at €600 million to €650 million, is still more than €100 million above target.

Researchers on BepiColombo are not the only ones worried. “We're all biting our nails,” says Richard Harrison of the Rutherford Appleton Laboratory near Oxford, UK, who works on the Solar Orbiter mission proposed for 2013. “If you look at the list of approved missions, Solar Orbiter is right at the end. It makes you feel kind of vulnerable.”

The reasons for the science programme's money problems are twofold. First, it is still recovering from overruns on the Herschel– Planck mission, which forced the agency to cancel the planet-hunting telescope Eddington in 2003. The Herschel infrared observatory and the Planck satellite, which will measure the cosmic microwave background, are due to be launched together in 2007 and are €178 million over budget.

“It was a big hit,” says David Southwood, ESA's director of science. He says the agency is clamping down on missions whose costs spiral, and may cut projects that cannot meet their original budgets. “We are being much more hard-nosed,” he adds.

If we had done badly we know we could be punished. But how could we be more successful than now?

The other factor is that member countries' contributions to the science programme, which makes up 12% of ESA's overall budget, are mandatory, so members must unanimously agree to any increase. The programme's purchasing power has fallen by 20% since the mid-1990s as payments have failed to match inflation.

Scientists and agency officials are not optimistic about that changing this year, and are urging ministers to reflect on recent successes of the programme. It has 16 operational spacecraft and can boast the notable achievements of Mars Express and Huygens, which touched down on Saturn's moon Titan earlier this year (see page 538), as evidence of their track record. “If we had done very badly, we know we could be financially punished,” says Coradini. “But how could we be more successful than we are now?”

He and other officials have asked ministers for a 2.5% year-on-year increase in funding, amounting to about an extra €100 million between 2007 and 2011. That would still leave a shortfall, but Coradini is optimistic: “If we get that amount of money, I think we will not only see the light at the end of the tunnel, we could get out of the tunnel.”