Once perceived as distant, cold, dark, and seemingly unknowable, Pluto had long been marked as the farthest and most unreachable frontier for solar system exploration. After Voyager accomplished its final planetary reconnaissance at Neptune in 1989, Pluto and its cohort in the Kuiper Belt beckoned as the missing puzzle piece for completing the first reconnaissance of our solar system. In the decades following Voyager, a mission to the Pluto system...