Which NASA mission made the first close flyby of Pluto in 2015?

New Horizons made the first close flyby of Pluto on July 14, 2015.

NASA launched the spacecraft on January 19, 2006, aboard an Atlas V rocket. It used a gravity assist from Jupiter in 2007 to increase its speed and test instruments before continuing through the outer Solar System. During the Pluto encounter, New Horizons photographed mountains of water ice, nitrogen glaciers, layered atmospheric haze, and the heart-shaped Tombaugh Regio.

The spacecraft could not enter orbit around Pluto because the mission required a high-speed trajectory and carried limited fuel. Instead, it gathered observations during a carefully planned flyby and transmitted the data back over many months. New Horizons later flew past the Kuiper Belt object Arrokoth on January 1, 2019.

Voyager 2 visited several outer planets but never flew past Pluto. Dawn explored Vesta and Ceres, making New Horizons the mission associated with Pluto’s first detailed reconnaissance.