By Paul Rincon

BBC News science reporter



The ability to drill under the surface is a "must have"

It aims to send a single robot rover to the Martian surface along with another, stationary, science package.

The European Space Agency (Esa) had also been considering a mission concept from the British team behind Beagle 2, but this is no longer on the table.

However, the Beagle team could yet see their science instruments, or ones derived from them, carried on the 580-million-euro mobile laboratory.

A three-day meeting next week at the space agency's European Space Research and Technology Centre in Noordwijk, the Netherlands, will discuss what experiments the craft should take to Mars, and the UK team has submitted its own ideas and proposals.

Two-pronged mission

Their BeagleNet concept for the mission - which envisaged dropping two small rovers on the planet - has fallen out of the running and Esa has opted instead for the single rover concept loosely referred to as ExoMars.

The Mars lander is part of Esa's Aurora programme, a long-term plan for robotic and - potentially - human exploration of the Solar System, with Mars, the Moon and the asteroids as likely targets.

Esa is no longer entertaining the BeagleNet concept

"The fixed station and/or the rover may contain elements of a Beagle 2-type payload. Whether it does or not is very much dependent on the discussions next week."

A primary objective of the mission is to search for signs of past or present life; it will leave Earth in June 2011 and arrive at Mars in June 2013.

Vital tools

Esa is currently aiming at a mass of 120kg for the rover and 8-14kg for the science payload, said Dr Sims.

"Must haves" for the rover payload include a drill or "mole" for burrowing beneath the Martian soil and an experiment for detecting past or present life, in addition to the other instruments.

EUROPE'S MISSION TO MARS To leave Kourou, French Guiana, spaceport in 2011 Will launch on Russian-built Soyuz-Fregat vehicle Planetary positions account for long journey time Landing date will avoid worst of duststorm season US may be asked to provide orbital relay of data Could employ parachutes, airbags and retro-rockets

The European agency is looking at using US spacecraft in orbit around Mars to relay data from the lander to Earth. In return, US instruments could be placed on the mission's science payload.

It had also planned to seek American hardware for the lander's entry, descent and landing systems. But this has fallen foul of US budget limitations and a legal regime there known as Itar (International Traffic in Arms Regulations).

The Itar export regulations are designed to protect sensitive military technology falling into the wrong hands. But they also apply to satellite technology, including entry, descent and landing systems.

Collaboration talks

Despite Esa's decision to go with the ExoMars concept, there may yet be hope for BeagleNet. Professor Colin Pillinger, lead scientist on the Beagle 2 mission, is still convinced of the merits of a small twin rover mission.

He and colleagues have started informal discussions with other space agencies about the possibility of a joint collaboration based on just such a concept.

Dr Sims said there could be openings in Nasa's robotic exploration programme for such a project, in particular a low-cost "scout" mission opportunity scheduled for launch in 2011. However, this would be in open competition with US teams.

The outcome of discussions next week on the science package for Europe's Martian rover mission will go to the Aurora programme board and other Esa bodies for approval.

The agency's member states will then have to sign off the mission. Ministers will have their say when the Esa Council meets on 5 and 6 December.