Final answer:
New Horizons is the spacecraft that launched in 2006 and flew by Pluto in 2015 before exploring the Kuiper Belt.
Step-by-step explanation:
The mission that was launched in January 2006 and made a flyby of Pluto in July 2015 is New Horizons. After its encounter with Pluto, the New Horizons spacecraft continued its journey into the Kuiper Belt, conducting a flyby of a Kuiper Belt Object named Arrokoth (2014 MU69) on January 1, 2019. This mission has significantly expanded our understanding of the outer solar system, revealing that these distant objects are much more varied and geologically active than was previously thought.