Fission-assisted or self-sustaining gasdynamic mirror propulsion system

Abstract

A controlled fusion system that can be achieved with almost present-day or near-term technology is proposed as a propulsion device that could be utilized for interplanetary and interstellar space exploration. It is based on the Gasdynamic Mirror (GDM) which, when operated as a propulsion engine, is capable of producing specific impulses in excess of 200,000 seconds, and thrusts of tens of kilonewtons. This capacity stems from the fact that at a sufficiently high plasma density the collision mean free path is significantly shorter than the machine length, allowing the plasma to behave much like a fluid with confinement properties that are substantially different from those which characterize the standard collisionless mirror. Under these circumstances the plasma escape from the end is analogous to the flow of a fluid into a vacuum from a vessel with a hole. Using an appropriate set of conservation equations we have deduced the plasma parameters that underlie the propulsive capability of GDM. We have also carried out a preliminary engineering analysis to estimate the masses of the major components, and have concluded that such a system can be constructed with present day, or near term technology that has been developed by the world effort in terrestrial fusion power research. When applied to a manned mission to Pluto, it is shown that with GDM a round trip to the outermost planet in the solar system can be done in slightly over four years.