By Helen Briggs
BBC News science reporter
Ministers from 17 European countries are meeting in Berlin to discuss the future of Europe's space programme.
They will decide whether to give the go-ahead to a series of space missions proposed for the next decade.
A robotic Mars probe, a replacement for the lost Cryosat ice mission and a satellite network to monitor the Earth are all vying for funding.
The talks are regarded as pivotal to the future of Europe's space industry amid shrinking commercial markets.
At this year's annual ministerial meeting, the European Space Agency (Esa) is asking its 18 member states (17 European countries and Canada) to contribute 8.8bn euros (£5.9bn) for mandatory and optional space programmes.
This is made up of 3.1bn euros (£2.1bn) to fund the mandatory science programme until 2010, and a further 5.7bn euros (£3.8bn) to carry on with optional programmes and start new ventures.
New space proposals being discussed include:
Other key issues to be discussed at the two-day meeting include:
- The ExoMars mission to put a lander on the Red Planet. Planned for 2011, it would explore for biology on our near neighbour.
- Work to define programmes that would lead to European cooperation on possible human missions to the Moon and Mars.
- The next phase of a programme to launch a series of satellites to monitor the health of the Earth, including building Cryosat 2, which would replace the ice-monitoring probe lost on launch in October.
- Implementing the GMES (Global Monitoring for Environment and Security) programme to improve environmental monitoring and policy making in Europe.
Although the commercial market for space activities has witnessed a sharp decline in recent years, public expenditure on space is on the increase.
- Proposals to join forces with Russia on its new spaceship, the Clipper, which will eventually replace the Soyuz capsule.
- Europe's access to space via the French-led Ariane 5 rocket and the Italian-led Vega rocket, which is currently in development.
This makes the decisions taken at the Esa ministerial meeting all the more important, as much of the money approved at the gathering will find its way into Europe's aerospace industry.
Member states have been finalising their funding priorities in the run-up to the Berlin summit.
Observers say it is highly unlikely that all programmes will be fully funded, necessitating intense rounds of discussions both at the table and behind the scenes.
Ministers are expected to give the go-ahead to funding that would secure the future of Cryosat, regarded by scientists as a key tool in monitoring climate change.
However, the future of GMES, the subject of intense lobbying in the UK, seems less certain.
Britain, with its stated interest in climate change, should be one of the lead players in the project; but there are fears in the UK space sector that the money from its own government to carry that interest through may not be forthcoming.
British environment minister Elliot Morley told the BBC News website this week: "We have a negotiating position, obviously, and we'll have to see what others put on the table.
"But we're committed to GMES and we're hopeful of a positive outcome for Britain."
WHAT IS THE GMES PROJECT?
A joint initiative of the European Union and Esa
Pulls together all Earth-monitoring data whether collected in space or not
Will use existing and newly commissioned spacecraft
Crucial to the understanding of how our climate is changing
Important for disaster monitoring - earthquakes, floods, eruptions, etc
An enforcement tool for EU policies: fishing quotas, etc
The European component of a global project known as Geoss
Launchers too are set to be the focus of heated discussion, particularly from countries such as Germany, France and Italy that invest heavily in rockets like the Ariane 5 and the newly developed Vega rocket.
Rachel Villain, Director of Space and Communications at the Paris-based Euroconsult agency, said there could even be calls for a ban on the use of non-European launcher vehicles, which is likely to be heavily resisted by some.
"Some people may ask for a ban on foreign vehicles to launch satellites; that would be a contentious issue," she told the BBC News website.
Space exploration, particularly dreams for human voyages to the Moon and the beyond, will also split member states.
"The content of the space exploration programme and the money for the space envelope programme may also be a subject of debate because of conflicting interests from the industrial and political viewpoint," she added.
"But this is the role of such an event - to have a consensus of what Europe wants to do in space in the long-term."