New Horizons (Pluto)

New Horizons completed the first-ever flyby of Pluto on July 14, 2015, traveling 4.67 billion miles in nine and a half years. The images demolished assumptions about the dwarf planet, revealing towering water-ice mountains, nitrogen glaciers flowing into smooth plains, and a vast heart-shaped basin named Tombaugh Regio. This mission outperforms even Cassini-Huygens in terms of speed, being the fastest spacecraft ever launched at 36,373 miles per hour relative to Earth, and it returned 50 times more data than expected from a single flyby. Its discovery of a geologically active world added a 40% greater variety of terrain types than previously modeled, setting a new benchmark for planetary exploration beyond the Kuiper Belt.