New planets, Dres, Pol, and Eeloo New resource system keeps track of fuel in a whole new way, there are seven stock resources: Solid fuel (which will be familiar), liquid fuel (which is used alongside oxidizer in rockets and with intake air in jet engines), oxidizer is used in equal proportions with liquid fuel, and rocket fuel tanks carry both in equal proportions, intake air is required to run jet engines, it is gathered by the air intakes, electricity is used to power probes, lights, rover wheels, and ion engines, monopropellant is just another name for RCS fuel, and xenon gas is used to power ion engines. Right click on a tank and then alt+right click on another tank to bring up the resource transfer system, where you can move fuel between any two tanks that are attached to your vehicle in any way. Probes. probes will cease to function if you do not supply them with electricity. Solar panels and RTGs are used to provide electricity. Also, a bunch of new probe-sized parts have been added. Docking. This brings a whole new challenge to the game, since before there were not very many good reasons to rendezvous with other craft in orbit. The manuever node system. Makes rendezvous actually manageable for new players, and almost easy for those of us who know what we're doing. Also, it makes everything else you do in orbit easier. Cosmetic re-entry effects. That should be a fairly exhaustive list of new things.