After nine years in flight, next week NASAs New Horizons spacecraft will finally begin science observations of Pluto and its burgeoning system of five known icy moons. On July 14, the spacecrafts flyby to this dwarf planet system will culminate in a 10,000 km closest approach that should really knock your socks off, mission team member Will Grundy told Forbes. Grundy says the flyby may even confirm the existence of wind-swept surface dunes of ice and soot leftover from a time when Pluto may have had much more of an atmosphere than today.

New Horizons represents humanitys closest virtual approach to the icy body which lies so far out that it takes some 248 years just to make one orbit around our Sun.

But why spend $700 million and nearly a decade en route to explore what some would argue is just a collection of frozen rocks?

Artists impression of Plutos surface with its moon Charon and a distant sun in its sky. Credit: ESO/L. Calada Pluto

Technically, Pluto which spans slightly less than 1500 mi in diameter, or not even two-thirds the diameter of our own Moon is a member of the Kuiper Belt, a giant reservoir of planetary debris left over from the solar systems formation some 4.56 billion years ago.

Although when the mission was first proposed there was concern that Plutos atmosphere would have already frozen out and collapsed before the spacecraft arrived, Grundy now says that new thermal models conclude that Plutos atmosphere never collapses.

Grundy would like to know if Pluto would have been significantly different a few hundred million years ago? Does it episodically have a bigger atmosphere because material escapes from the interior? And has it lost most of the atmosphere; or is it in a phase where its atmosphere is larger than usual or smaller than usual?

Although Plutos surface is probably not completely ice, its main composition is known to be nitrogen ice, carbon monoxide ice, and methane ice.

When you look at Pluto with the Hubble Space Telescope, you see a really blotchy surface with really dark areas and very bright areas, said Grundy. The conjecture is that those bright areas are ices and the dark areas are some older dirtier type of substrate.

Grundy says Plutos surface may even have some sort of hydrocarbon gunk, chemically not that different from crude oil or tar. But unlike oil at room temperature, these frozen molecules, he says, would behave more like rock particles than the gunk one might find on the floor of your local garage.

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Pluto May Harbor Wind-Whipped Dunes Of Ice And Soot