astroengine writes "On Feb. 10, NASA's Pluto-bound New Horizons probe entered the homestretch of its mission. When you are sprinting across the solar system, 'homestretch' is the final 1 billion miles of your journey. That sounds like quite a long stretch! But the half-ton spacecraft has already logged 2 billion miles since its launch in early 2006. That's twice the distance between Earth and Saturn. Though the icy dwarf planet is still three years away from its close encounter, mission scientists call this the Late Cruise phase of the flight."