This image of Pluto, taken by New Horizons after a 9.5-year journey, is our highest-resolution photo of the dwarf planet since its discovery by Clyde Tombaugh in 1930. (Photo courtesy of NASA via DOE)

By Matt Dozier

​NASA’s New Horizons spacecraft just accomplished one of the most exciting feats in the history of space exploration. After a 9.5-year, 3-billion-mile journey, the mission’s historic flyby of Pluto has provided us with our first-ever closeup views of the frozen world at the edge of the solar system. It’s a remarkable achievement, one that wouldn’t have been possible without careful planning, ingenuity—and a little help from the U.S. Department of Energy.

In 2006, when NASA engineers were designing New Horizons, they knew that it would need a long-lasting, compact and incredibly reliable power source to survive the cold, dark reaches of outer space.

Solar power was out of the question. The spacecraft’s itinerary would take it billions of miles from the center of the solar system into the realm of Pluto and the Kuiper Belt. That far out, the Sun shines with just a tiny fraction of the intensity we see here on Earth—scarcely brighter than the stars in the night sky. Other options like batteries or fuel cells wouldn’t last long enough. [Read more…]