There are many new concepts currently being examined in the field of advanced rocket propulsion. Listed here are a few links to areas of solar sails, nuclear rockets, geometrodynamics, and laser propulsion. Solar sails work like regular sails on an Earth-stuck ship, however, instead of regular wind, solar sails use light pressure, from the sun or lasers. Here's a few links to solar sail web sites: http://www.spaceviews.com/1998/08/article3a.html http://hyperion.advanced.org/19455/solar_sails.htm http://www.ec-lille.fr/~u3p/index.html http://www.ugcs.caltech.edu/~diedrich/solarsails/ http://www.astro.keele.ac.uk/~aa/pages/sails.html Nuclear rockets use a nuclear reactor to heat the propellant gasses which are then forced out a nozzle to get thrust. Currently the designs call for the use of fission reactors, although with luck, fussion reactors will be working soon. Here's some more links. http://rintintin.colorado.edu/~martinal/NTRfinal/index.htm http://ans.neep.wisc.edu/~ans/point_source/AEI/sep95/rocket.html Geometrodynamics is the bending of space to be able to move a place to your spaceship instead of moving your ship to that place. As one of my friends put it, "Instead of going to the mall to get a Cinnabon, geometrodynamics brings the mall and the Cinnabon to you." http://www.physics.gla.ac.uk/gwg/geodynamics.html http://www.lisa.uni-hannover.de/shared/gravinfo/index.html Laser propulsion uses a ground based laser, beamed to your ship, to heat your propellant. A small vehicle using this technology is currently being flight tested at White Sands, New Mexico. http://www-aero.meche.rpi.edu/Research/LaserPropulsion/index.html One of the leaders in space propulsion research is the Air force Research Laboratory at Edwards Air Force Base. They have facilities for electric propulsion research, large rocket test stands, altitude facilities, and a lot of other really labs, including my favorite, the National Hover Test Facility. Air Force Research Lab Rocket Propulsion Directorate Another organization involved in advanced propulsion of many various types, airbreathing and rocket, is DARPA, the Defense Advanced Research Projects Agency.