Triton

The largest of Neptune's moons, Triton is a unique captured Kuiper Belt object that orbits backwards around its planet and has active nitrogen geysers erupting from its frigid surface.

A spacecraft launched in 2013 that has been studying Mars' upper atmosphere, solar wind interaction, and atmospheric loss processes, helping scientists understand how the Red Planet lost most of its air and water over billions of years.

1 Ceres

The largest object in the asteroid belt and the only dwarf planet in the inner Solar System, Ceres is a spherical body composed primarily of rock and ice, with a dark, heavily cratered surface and mysterious bright spots of salt deposits in its Occator crater.