By Jonathan Amos
Science reporter, BBC News, The Hague
The International Space Station is very important to Germany
The money needed to exploit the space station was the big sticking point on the first day of discussions about the future of the European Space Agency.
The 18 member states of Esa are meeting in The Hague to try to agree an activity budget totalling 10.4bn euros.
The station is the single biggest item at 1.4bn euros, but Germany says this sum is simply too small to cover all of Europe's commitments to the platform.
And in discussions with France and Italy, it sought a major increase.
The BBC understands that a small group broke out from the main meeting in an effort to resolve the issues.
But on much of the rest of the budget, which covers mostly the next three years, there has been wide agreement among the delegations.
"I am very satisfied because this ministerial meeting shows great ambition," the French research minister Valerie Pecresse told BBC News. She said she expected a substantial increase in spending compared with the last Council Meeting of Esa in 2005.
France and Germany are the biggest investors in the European Space Agency, and provide the lion's share of the funds needed to run Esa's most expensive programmes - the space station and the Ariane rocket programme.
But whereas the funds requested here at Esa's Council Meeting to improve the performance of Ariane did not prove to be contentious, the space station budget has required some hard negotiation.
The Esa director general is confident all difficulties can be overcome
The station is a key programme for the Germans. The control centre that looks after the European element on the station - the Columbus science lab - is based in Oberpfaffenhoffen. Germany led the production of Columbus, and the contract to manage Europe's contribution to the space station is run through the German arm of aerospace contractor EADS Astrium.
The meeting had been asked to approve 1.38bn through to 2012. Germany claims this would not adequately cover all the costs involved, and argued that the budget be raised to more than 1.75bn.
The German delegation warned that the original request would not cover the costs of launching Europe's space freighters, the robotic ships that will become the main way of re-supplying the space station once the US shuttle fleet is retired.
Esa Council Meetings are always held in closed session and the compromise that will inevitably emerge on this issue will not be made public until Wednesday.
"I am confident we will fix these last issues," said Esa director general Jean-Jacques Dordain. Making light of the differences, he added: "There will be no night-shift for ministers, only executives of Esa who have to finalise some text. The ministers will have dinner."
Mrs Pecresse told BBC News: "We all had a nice talk this evening. We're trying to make a compromise. I can't tell you what it will be but I hope everything will be settled by tomorrow."
A budget for the Mars rover project is still short of where it needs to be
The minister said she was delighted that all her country's priorities had been met and said France's contribution to Esa was set to rise from the 1.6bn euros pledged in 2005 to 2.3bn for the 2009-2011 period.
Along with the space station, one other issue on the agenda here in The Hague is still some way short of being resolved, and it affects British interests particularly.
It concerns the budget for ExoMars, a robotic rover that Esa plans to send to the Red Planet in 2016.
The UK has put its financial muscle behind the mission but in the three years since ministers initiated the project, it has grown in scope and cost. The Hague meeting must sign off this "enhanced ExoMars", but it is understood the delegations are still many tens of millions away from committing the one billion euros required.
The British delegation has not released any details about the status of the negotiations.