The decision to build a Mars Rover was taken government / national level by all of the European countries getting together and deciding that they want to show that they have the capability to do impressive, difficult, complex engineering challenges and to provide new scientific data supporting the hunt to find life outside of Earth . . . a bit like the old question . . . “Why climb a mountain? Because it is there” . . . we are doing it for the art of it. A rover the only way we have at the moment of getting up-close-and-personal with Mars to do specific, complex measurements of the soil.