  Direct imaging and characterization of extrasolar Earth-like planets is
strongly impacted by the orbital inclination of the planet to be studied, as a
combination of pure geometrical effects and the impact of exozodiacal dust.
Here, we perform simulations to quantify the impact of a priori knowledge of
inclination for the efficiency of a typical coronagraphic or occulter-based
mission. The relative impact and complementarity with prior knowledge of
exozodiacal brightness down to achievable levels is examined and discussed. It
is found that inclination has an even greater impact than the exozodiacal
brightness, though the two have excellent complementarity. We also discuss
different methods for inclination determination, and their respective
applicability to the context of precursor science to an imaging mission. It is
found that if technologically achievable, a combined effort to determine
inclinations and exozodiacal brightnesses with ground-based facilities would
substantially increase the efficiency of a space-based dedicated mission to
image and characterize Earth-like planets.
