A Hubble Telescope image of Pluto and its three largest moons: Charon, Hydra, and Nix
Image Credit: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI) and the HST Pluto Companion Search Team
As of 2006, Pluto had 3 known moons as pictured above: Charon, Nix, and Hydra. By 2011, two more were added with less creative names — P4 and P5. But astrophysicist might need to add up to 10 more members to Pluto's family of known moons according to a recent suite of simulations.
The simulations revealed that Pluto may have many more relatively tiny satellites roughly one mile across each. The satellites, if they exist, likely formed from accumulating dust that encircles the dwarf planet. Earth-based telescopes have trouble seeing these tiny moons, but the New Horizons spacecraft should be able to detect them when it reaches Pluto in 2015.