Establishing the infrastructure - An integrated Space Transportation System

A discussion is presented concerning the various transfer vehicle/propulsion systems that are currently under consideration within the egis of the NASA Space Exploration Initiative for the establishment of an infrastructure for lunar base construction and Mars exploration. Cryogenically fueled and nuclear propulsion alternatives are considered, as well as such advanced concepts as that employing nuclear-electric propulsion and artificial gravity and a solar-electric propulsion zero-gravity concept. Mars lander and earth-to-LEO launcher concepts are also noted.