Complex sentence: On September 11,2014, "Curiosity" reached the base of Aeolis Mons (or Mount Sharp), the rover mission's long-term prime destination and where the rover is expected to find more information about the history of Mars.
Split into simpler sentences: On September 11,2014, "Curiosity" reached the base of Aeolis Mons (or Mount Sharp), the rover mission's long-term prime destination. The rover is expected to find more information about the history of Mars.