By Jonathan Amos
Science reporter, BBC News
NEW EXOMARS MISSION CONCEPT
Now likely to leave Earth in 2018; primary aim is to search for life
Current proposal is to use a US Atlas rocket to launch ExoMars
US also to look after the rover's entry, descent and landing
Hardware likely to be the same as for US 2013 rover, Curiosity
ExoMars would be targeted at key methane hotspots on the planet
It will have the capacity to drill 2m into the Martian ground
Esa states still have to sign off the final plan and a budget
Member-states of the European Space Agency (Esa) have given final approval to revised plans to explore Mars.
There have been protracted discussions on what Europe could do at the Red Planet and how much it might cost.
The Council of Esa has given the green light to a two-mission endeavour that would see the launch of an orbiter in 2016 and a rover in 2018.
The exploration projects will be undertaken in partnership with the US space agency (Nasa).
Esa's Council of Ministers has approved an initial budget of 850 million euros to support the missions. It will need to increase the cash available by about 150 million euros in future years.
"This marks an important moment for Europe in its steps towards space exploration on the world scale," said Professor David Southwood, the director of science and robotics at the agency.
"We have been to the planets before, sure. But now we have a plan for exploration ahead to build our technical capability and explore Mars in a long-term partnership."
The two-mission scenario has been born out of a much smaller proposal passed in 2008 which had the idea of launching a technology-demonstration rover to Mars in 2011 known as ExoMars.
Technical considerations that saw this concept grow in scope and cost meant the whole endeavour was revised.
The 2016 orbiter would be designed to track down the sources of methane and other trace gases recently detected at Mars. The presence of methane is intriguing because its likely origin is either present-day life or geological activity.
Confirmation of either would be a major discovery.
The 2018 ExoMars rover - now a much bigger vehicle - could then be targeted at one of the most interesting sources.
The 2016 mission would also have sufficient mass margin to put some sort of lander on the surface, although this would stay in just one location and may not be very long-lived.
Even so, Europe is keen to have a go at putting down some sort of instrument package on the planet to gain expertise in entry, descent and landing technologies.
David Southwood told BBC News that the programme was "on the road in that full implementation of the hardware build will now start".