The ExoMars mission's scientific objectives, in order of priority, are:

1. To search for signs of past and present life on Mars.
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2. To characterise the water/geochemical distribution as a function of depth in the shallow subsurface.

3. To study the surface environment and identify hazards to future human missions.

4. To investigate the planet's subsurface and deep interior to better understand the evolution and habitability of Mars.