When Pluto was originally discovered in 1930 it was designated the 9th planet. Starting in 1977, however, astronomers began to discover other icy objects in the outer solar system and in 2006 a vote of the International Astronomical Union (IAU) formally reclassified Pluto as a dwarf planet.

In that same year, 7 months prior to the vote, NASA launched the New Horizons spacecraft to explore Pluto and the other objects in the outer solar system. Next year, after a 10 year, 3 billion mile journey, New Horizons will arrive at its destination.

“Not only did we choose the date, by the way, we chose the hour and the minute. And we’re on track. We’re arriving at Pluto on the morning of the 14th of July 2015. It’s Bastille day. To celebrate, we’re storming the gates of Pluto,” said Alan Stern, the principal investigator for NASA’s Pluto-Kuiper Belt Mission to NPR.

Researchers already know the basics about Pluto. Pluto is small, about two-thirds the size of Earth’s moon. We know that it has 5 small moons or satellites and that it takes 247 years to orbit the Sun. However, every mission to a new planet or region of space delivers surprises.

“When we first sent missions to Jupiter, no one expected to find moons that would have active volcanoes. And I could go down a long list of how often I’ve been surprised by the richness of nature,” said Stern.

In addition to sending back photos of Pluto, New Horizons will also be sending back the first clear photos of the Kuiper belt, a dark region of space beyond the planets which is home to at least three dwarf planets and at least 100,000 other objects including comets and asteroids.

Because the object in the Kuiper belt and the Oort cloud are distant, cold and most of them are small, it has been difficult to observe them from Earth. The Deep Horizons mission could tell us a great deal about what lies in the outer solar system and potentially about how our solar system was formed.