New Horizons: Rediscovering Pluto

Mankind's first close-up look at Pluto did not disappoint: The pictures showed ice mountains about as high as the Rockies and chasms on its big moon Charon that appear six times deeper than the Grand Canyon. Especially astonishing to scientists was the total absence of impact craters in a zoom-in shot of one otherwise rugged slice of Pluto. That suggests that Pluto is not the dead ice ball many people think, but is instead geologically active even now, its surface sculpted not by collisions with cosmic debris but by its internal heat. Breathtaking in their clarity, the long-awaited images were obtained by NASA's New Horizons, the unmanned spacecraft that paid a history-making flyby visit to the dwarf planet on July 14, 2015 after a journey of 9½ years and 3 billion miles. Experience the voyage to Pluto and rediscover our solar system through the photographs and reporting of The Associated Press.

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Marcia Dunn is the aerospace writer for The Associated Press, based at NASA’s Kennedy Space Center in Florida. She has covered the space beat since 1990 and written extensively about the human side of space exploration. She witnessed and covered 99 space shuttle flights, chronicling the completion of the program in 2011, and has shifted more of her focus to astronomy and robotic missions. The New Horizons mission to Pluto has turned out to be one of her favorite all-time stories.