Germany’s decision to join Europe’s space-exploration program after a nearly four-year boycott increases the likelihood that European governments will approve a $700 million Mars lander and rover when they meet in December, European government officials said.

Officials cautioned that the ExoMars project — which would look for current or past life on Mars and continue on the martian surface research that Europe is doing from orbit with its Mars Express satellite — is by no means assured of approval by European Space Agency (ESA) government ministers. The ministers currently are scheduled to meet in December in Berlin to set ESA’s medium-term budget and program priorities.

But Daniel Sacotte, head of ESA’s human space flight, microgravity and exploration programs, said that ExoMars probably could not proceed without substantial German involvement.

The German space agency, DLR, announced July 12 at a meeting of ESA’s exploration program board that it would invest 3 million euros ($3.6 million) in the agency’s Aurora exploration effort, which is now focused on ExoMars.

The German contribution brings total space exploration funding to 44.5 million euros. Italy is leading the program so far, with a 12 million-euro commitment, with Britain, France and Germany taking lesser shares and other ESA governments at even lower levels of participation.

Germany’s decision “illustrates that ExoMars is increasingly seen as a major mission for Europe,” Sacotte said in a July 12 interview. “Germany has an awful lot of industrial capacity to bring to the mission. It’s clearly good news that Germany has joined Aurora.”

The ExoMars mission, with a scheduled launch in 2011, carries an estimated price tag of 580 million euros . Annual spending would start at 20 million euros in 2006 and rise to 140 million euros in 2009 before declining through 2013.

The current 45 million-euro exploration program, scheduled to end in 2006, is intended to begin studies of what a European space-exploration program would look like, and to permit interested governments to set early place-markers on program elements they want to reserve for their domestic industry.

Germany’s science representative on ESA’s space exploration program board, Wolfgang Frings of DLR, said Germany changed its mind on Aurora mainly because of the attractiveness of the ExoMars mission and ESA’s decision to put the astronaut-related exploration aspects in the closet for the time being.

ESA’s early Aurora space-exploration proposal appeared astronaut-centered, with manned lunar and Mars missions given prominence. The move to place robotics at the front of the program helped persuade Britain to join in 2004 and has had the same effect on Germany.

“Aurora at the beginning was a bunch of flowers,” Frings said July 13. “You could see billions of euros being spent on it. The Mars sample-return proposal alone was well over a billion euros. This made no sense for us. But now we have an end-to-end mission, ExoMars, with reduced ambitions — no more orbiter, for example. No one has committed to the full project yet. That is for the ministers to decide. But we can see a way forward now that the mission budget is credible.”

ESA originally had viewed ExoMars as a mission to be conducted bilaterally with NASA. But in recent meetings between the two agencies, NASA officials made clear that current U.S. technology-transfer restrictions would make it impossible for NASA to provide the ExoMars entry, descent and landing system.

NASA’s position will force ESA to develop its own entry, descent and landing system, a technology that also will be needed if Europe ultimately resurrects the Mars sample-return mission.

In addition to ExoMars, ESA is expected to propose to the December ministerial meeting a four-year technology-development program to accompany ExoMars and future exploration missions. The budget of 150 million euros would be spent between 2006 and 2009.

Another reason for Germany’s hesitation to join the exploration effort was concern that it would steal engineering and financial resources from the international space station. Germany is Europe’s biggest contributor to the station. Europe’s Columbus laboratory has yet to be attached to the station and is awaiting a U.S. space shuttle launch date.

“We need to be clear: The station is still our first priority,” Frings said. “That has not changed. The exploration program is focused on robotics.”

Peter B. de Selding was the Paris bureau chief for SpaceNews.