Paris

Europe's troubled Rosetta comet mission has a new target, but it is not out of the woods yet — a lack of funds still threatens the project.

The Rosetta craft, which is designed to land on a comet, was scheduled for lift-off in January this year, but the launch was postponed as a result of technical problems with the new class of Ariane rockets used by the European Space Agency (ESA). The delay meant that the probe missed the window to reach its original target, the comet Wirtanen (see Nature 421, 301–302; 200310.1038/421301a).

At a meeting of ESA's science committee last week, officials confirmed that the new target will be the comet Churyumov-Gerasimenko. But before the launch, which will take place on 26 February 2004 on a standard Ariane 5 rocket, extra money must be raised. The cost of storing the satellite and redesigning the mission will be some €70 million (US$82 million).

David Southwood, ESA's head of science, says that nobody wants Rosetta to be cancelled, especially as most of its costs have already been paid. But ESA's science programme is facing a cashflow crisis. Problems with the Ariane rockets have added to the costs of several planned missions, and a downturn in the commercial space market means that ESA's industrial partners are now demanding more money up front for their involvement in collaborative projects.

Last week's meeting heard that ESA's science budget is facing an overrun of €140 million this year, and this is set to increase in the following two years. To launch Rosetta, the science programme will need a loan from ESA's governing body.

ESA has also had to pay out more than €70 million to support scientists building instruments for its Herschel infrared space observatory and for its Planck mission, which will study cosmic microwaves. Both projects are slated to launch together in 2007. ESA traditionally pays spacecraft and launch costs, with member states footing the bill for instruments. But the agency is increasingly having to pay for instruments, and officials say that future payloads will be subject to contracts requiring member states to commit to full funding for the project's duration.