Current Trends and Challenges in Electric Propulsion System Integration
Vadim Khayms
Lockheed Martin Space Systems Company, Sunnyvale, CA
Seminar Abstract
On-board propellant has been a major contributor to the overall spacecraft mass on most commercial, scientific, and military satellites. As many of these missions generally require a wide range of on-orbit functions, including orbit raising, station-keeping, and attitude control, the use of high performance electric propulsion offers significant weight savings and improvements in weight-to-orbit capability. To take advantage of these benefits, Lockheed Martin has recently developed and completed qualification of a Hall Thruster Propulsion System for use on its future commercial and military programs.
It is well known that plasma plumes present significant challenges to spacecraft integration. Among the numerous effects, impingement of energetic plume ions, causing sputtering of spacecraft surfaces and contamination due to re-deposition of eroded material are considered most critical. Erosion and contamination affect electrical and thermal properties of sensitive spacecraft surfaces and may degrade optical sensors and solar arrays over time. Other effects of the ionized plume include attenuation and modulation of communication signals transmitted through the plasma, electromagnetic interference of thruster radiated and conducted emissions with sensitive electronic equipment, increased susceptibility to static discharges in substorm environments, neutralization of differential charging by the plume, effects of spacecraft potential on surface erosion rates, just to name a few.
Over the past several years, in parallel with hardware development, Lockheed Martin pursued a comprehensive modeling and testing program aimed at gaining a quantitative understanding of electric propulsion plume effects. Multiple analytical and numerical tools were developed and validated through test to address a number of key integration concerns. The talk will provide an overview of the challenges associated with the integration of electric propulsion and the tools developed to assess the impacts. Modeling deficiencies and limitations of existing computational tools as well as a wish list of desired modeling capability will be discussed to stimulate interest within the community.