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The lifetime of Mars Express, the fast and cheap voyage to Mars proposed by the European Space Agency (ESA), could be doubled following an offer from NASA and the Italian Space Agency (ASI) to provide the mission's telecommunications system and other assistance.

Under a suggested three-way deal, ASI will build a 64-metre radioastronomy dish, while NASA's equipment would allow the voyager to relay data from the US space agency's Mars Lander in 2005. The Italian agency has also offered to consider providing ground support for the mission. The cost of ground support would increase significantly since the proposed agreement would extend the mission's life from two to four years.

The politically popular Mars Express mission, which it is hoped to launch in 2003, comes up for formal approval by Europe's research ministers in November. Last week's meeting of the agency's Science Programme Committee (SPC) accepted the trilateral agreement in principle. The deal could be ready for signing as soon as the mission is formally approved.

By cutting the overall costs of both ESA's and NASA's Mars missions, the agreement will allow the scientific returns to be increased, says the SPC. It would also open the door to closer coordination of the two agencies' Mars missions, something that both sides would like to see.

Giovanni Bignami, ASI's director of space science, says that the Italian end of the telecommunications package would be paid for by ASI's technology programme, rather than its science programme, so there is no danger that it will impact on ASI's funding of other ESA science projects such as the cometary mission Rosetta.

The telecommunications system would transmit and receive data from experiments and landers on the planet surface from the low orbit of Mars Express. So far, none of the 12 proposed landers for Mars Express has been approved by ESA, as none has secured the necessary assurances of national financing.

But the SPC approved a payload of seven on-board experiments including subsurface radio-imaging of the planet surface's structure, photographic and spectrometric imaging of the surface, atmospheric physics and magnetospheric physics.

ASI has offered the data collecting services of its radiotelescope currently being built in Sardinia, and which is partially funded by the European Union. This radiotelescope, scheduled to become operational in 2001, will be able to receive not only natural radioactivity from space but also data from planetary probes including Mars Express.

At last week's meeting, the SPC also overruled a proposal from ESA officials to merge two of the agency's planned missions, the ‘cornerstone’ Far Infrared Space Telescope and the cosmic microwave background surveyor Planck (see Nature 387, 639; 1997).

Although a merger would have saved a considerable amount of money, the SPC argued that the scientific return would have diminished to an unacceptable level.

The two missions will now share the same satellite, but will be physically independent. The proposed launch date for the two missions will now slip back one year, to 2007.