you could also use an ion drive or solar sails
~M

>
>The distance Sun-Pluto is around 40 AU (40 Astronomical Units, i.e., 40 times the distance Sun-Earth). That means that for any hypothetical inhabitant or visitor of Pluto, the Sun would seem 1/1600 as bright as for an inhabitant on Earth. For a start, that means it's really cold over there, apart from being dark. Also, spacecraft can most likely no longer use solar energy, and must instead use nuclear reactors.