With the recent excitement surrounding Dennis Tito's announcement of Inspiration Mars -- an ambitious plan to take advantage of the fortuitous close approach and send a couple on a flyby of Mars to leave Earth in 2018 -- it's easy become myopic and consider the planets of our solar system as the next logical step in our collective exploration of, and expansion into, space.
With that said, it's incredibly important to recognize that the planets are, from a technological and engineering standpoint, extremely challenging objects to both visit and ultimately return from due to their comparatively large gravitational fields.
Nuclear propulsion is an already obsolete 20th century technology, and will only be useful for inter-solar system travel. Interstellar travel will require an entirely different and much more radical method of propulsion. To read more, click here.