Munich

There was good and bad news last week for Europe's space scientists. Two projects believed to have been under threat — a mission to map star positions precisely and another to study the Sun — survived a meeting of European Space Agency (ESA) officials. But plans to send a spacecraft to Venus in 2005 were axed amid doubts over the project's timetable.

The demise of the Venus Express mission came in Ardenes in arctic Norway, where ESA's Scientific Programme Committee met to reassess the agency's scientific activities for the next 10 years. ESA has to save up to 200 million euros (US$184 million) during that period in response to budget cuts imposed last year by its members, which comprise 15 European states plus Canada (see Nature 415, 730; 2002).

Missed chance: Venus Express was originally expected to share facilities with Mars Express. Credit: ESA

Venus Express was to have carried out the first global survey of Earth's nearest planetary neighbour, including studies of its atmosphere and its interactions with the solar wind, the stream of charged particles emitted by the Sun. The mission had the potential to save money by using the same production facilities as Mars Express, an ESA mission that is scheduled to launch next year.

In the end, Venus Express was dropped because of diverging time schedules, says Giovanni Bignami, scientific director of the Italian Space Agency and outgoing vice-chair of the Scientific Programme Committee. The mission needed to be launched very shortly after Mars Express if the two were to share facilities, but funding for the spacecraft's 20-million-euro payload of scientific instruments, which was to come from individual member states, had still not been secured.

The decision shocked those involved with the project, and has left planetary scientists feeling cheated. “It came out of the blue,” says Dimitri Titov, a physicist at the Max Planck Institute for Aeronomy in Katlenburg- Lindau, Germany, and science coordinator for the cancelled mission. “We are losing a huge opportunity to study an under-explored planet.”

“It is absolutely regrettable,” agrees Michael Grewing, director of the Institute for Millimetre Radiowave Astronomy in Grenoble, and chair of the group of space scientists that advises ESA. His panel had argued in favour of the project. “We have missed the unique opportunity of putting together a full-range planetary mission for just one-third of the usual costs.”

Grewing points out that Venus Express would have fitted well in the six-year gap between the launches of Mars Express and Bepi Colombo, the planned 2009 mission to Mercury. He says that ESA should now look for ways to help Solar System researchers, such as increasing European participation in planetary missions run by NASA.

Two projects that ESA officials had previously hinted could be axed were retained at the Norway meeting. GAIA, an advanced astrometry satellite that will precisely map the brightness, colour and relative positions of a billion objects in the sky, could be launched by 2009 if development of the spacecraft's instruments can be completed in time. Space scientists hope that data from GAIA will improve their understanding of stars' inner workings, and help them to detect possibly tens of thousands of extrasolar planets, including small, Earth-like ones. Solar Orbiter, which will study the Sun from a distance of around one-fifth of the Earth's solar orbit, will be launched between 2008 and 2013 as planned.

GAIA → http://astro.estec.esa.nl/GAIA

Solar Orbiter → http://sci.esa.int/home/solarorbiter/index.cfm