When New Horizons lifted off on Jan. 19, 2006, it was the fastest spacecraft ever to be launched from Earth. The space probe was sent on a 3-billion-mile (4.8 billion kilometers) journey to a region known as the Kuiper Belt, an area of the outer solar system where the icy remains of our star system's formation are located. Nine and a half years later, New Horizons reached its destination, zooming past Pluto and capturing historic views of the surprisingly rich Plutonian system.
The observations from New Horizons will keep planetary scientists busy for years, but already the mission has revealed a world with flowing nitrogen glaciers, mountain ranges rivaling the Rockies, ice volcanoes and geologically active regions. Before New Horizons reached Pluto, scientists expected the dwarf planet would be an interesting place, but they never imagined anything like the incredible dynamic world the spacecraft revealed. [Pluto Flyby Anniversary: The Most Amazing Photos from NASA's New Horizons Mission]
Scientists have even used New Horizons' observations to reveal low-lying isolated clouds in the dwarf planet's thin atmosphere.
"If there are clouds, it would mean the weather on Pluto is even more complex than we imagined," New Horizons principal investigator Alan Stern, of the Southwest Research Institute, is quoted as saying in the new video.
Pluto's thin atmosphere also appears to be leaving deposits on the dwarf planet's surface, making it appear brighter than expected.
"The atmosphere can snow, making bright surface deposits," Stern added.
But Pluto wasn't the only target along New Horizons' journey. The probe also observed the dwarf planet's five known moons — and the largest, Charon, is a fascinating world in its own right. New Horizons managed to get some high-resolution views of the moon's surface, revealing structures that look like landslides — the first landslides observed in the Kuiper Belt.
Now, Pluto is far behind the probe, and New Horizons has been put on course for another flyby. On Jan. 1, 2019, the spacecraft will execute a close flyby of 2014 MU69, a Kuiper Belt object that is estimated to be about 20 miles wide (30 km) — more than 10 times larger and 1,000 times more massive than a typical comet.
"MU69's orbit indicates it is a cold classical Kuiper Belt object, one of the most primordial objects in the solar system," Stern said. "Additionally, a recent telescopic observation made from Argentina leads us to believe that MU69 may be part of a binary pair, or two objects orbiting one another."
After flying by 2014 MU69, New Horizons will continue its path to the farthest reaches of the Kuiper Belt, according to the video. By 2021, it will be more than 4.65 billion miles (7.48 billion km) from Earth — more than 50 times the distance from Earth to the sun — and will continue to explore the hinterlands of our solar system.