In the post-Voyager era of deep space flight, spacecraft propulsion designs feel like science fiction.  Instead of using rockets and a thermonuclear generator to produce heat, we have things like solar sails, laser sails, and ion propulsion.  These all take advantage of the vastness of space to create a slow-but-continuous acceleration that can get spacecraft moving at incredible speeds. Of course, even at incredible speeds it will still take decades to reach other stars, but compared to Voyager, it’s a step in the right direction. If you want to get to the outer solar system quickly, try the Heliopause Electrostatic...