Interplanetary travel and exploration can be greatly facilitated if indigenous propellants can be used in place of those transported from Earth. Nuclear thermal rockets offer significant promise in this regard, as in principle, any gas at all can be made to perform as a propellant to some extent.; In particular, the Martian atmosphere is composed of 95% CO{dollar}sb2{dollar}. Under Martian conditions, this gas can be liquified by simple compression to about 100 psi, and remains storable without refrigeration. When heated to 2400 K and exhausted out of a rocket nozzle, a specific impulse of about 226 s can be achieved. This is sufficient for flights from the surface to orbit or from one point on the Martian surface to any other point on the planet. Because the power requirements for acquiring CO{dollar}sb2{dollar} are quite low, the propellant acquisition system can travel with the vehicle, allowing it to refuel itself each time it lands. Thus this vehicle concept, which is termed a NAV (Nuclear Ascent Vehicle), offers unequalled potential to achieve planetwide mobility, allowing complete global access for the exploration of Mars, and potentially can reduce the initial mission mass in LEO as well.; This dissertation presents the results of an extensive study which centered on the conceptual design of a NAV vehicle with surface to orbit capability. Carbon dioxide was the propellant of choice, with some examination of alternate concepts using other propellants. The NAV configuration defined by the conceptual design was used as a basis for defining engine performance requirements, and a detailed study of a potential NAV engine that could meet these requirements was then conducted. The resulting NAV/engine combination was then examined in a series of trade studies to determine its potential merit in assisting in the exploration of Mars.
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