There has been many comments on us requiring a new form of propulsion, obviously not chemical rockets.
Nuclear pulse propulsion. Could take a manned mission to Pluto and back in a year. The trick? Dropping .15kt nukes out the back of the ship and riding out the shockwave. Extremely effective. The original design is from the early 60's. They even wanted to launch the ship from the ground using this trick, and pogo-sticking to orbit. Hiroshima was 50kt, so there's little threat about a nuke going "astray."