SPACECRAFT PROXIMITY OPERATIONS USING CONTINUOUS LOW THRUST

Recently, both DoD and NASA have demonstrated increased interest in the development of close proximity operations for space systems. AFRL's Advanced Sciences and Technology Research Institute for Astrodynamics (ASTRIA) has defined several key research topics relevant to military priorities, with one area of critical importance being the inspection and observation of low Earth orbit resident space objects (RSOs). This study investigates the feasibility of using an ion propulsion system to effectively and accurately facilitate resident space object inspection. This would allow for a spacecraft to utilize a single thruster for orbital maneuvering and proximity operations. More specifically, this research aims to determine the inefficiencies and challenges associated with using a fixed-thrust engine for autonomous RSO inspection and then proceeds to find resolutions for such challenges. A range of feasible circumnavigation distances that may be accomplished for a given fixed ion propulsion system thrust level is also sought to determine promising mission scenarios. These scenarios are then found for a series of different thrust levels and assessed to produce a topographical graph with the ion thrust level and the circumnavigation distance. This preliminary study shows promise for further investigation into the use of ion propulsion for proximity operations, including a novel path and controller design. Results are presented to demonstrate the feasibility of ion propulsion systems for use in spacecraft proximity operations in low Earth orbits.