Ion thruster having grids made of oriented pyrolytic graphite

Abstract

An ion thruster includes a source of a plasma of ions and electrons, and an ion-optics system located in sufficient proximity to the source of the plasma to extract ions therefrom. The ion-optics system has at least two domed grids arranged in a facing-but-spaced-apart relationship to each other. Each grid has a local reference vector that is perpendicular to the surface of the grid and a reference plane perpendicular to the reference vector. Each of the grids is formed of anisotropic pyrolytic graphite having an “ab” crystallographic plane that lies substantially in the reference plane. In one form, the “ab” crystallographic plane lies coplanar with the reference plane at all locations on each domed grid made of pyrolytic graphite. In another form, the “ab” crystallographic plane has a constant orientation at all locations on the domed grid. In yet another form, wherein the ion-optics system has an axis of thrust, the “ab” crystallographic plane of the pyrolytic graphite lies substantially perpendicular to the axis of thrust.

Dependencies are inferred from the claim text.