<p>A three-dimensional electrostatic numerical tool has been developed to analyze spacecraft and Hall thruster plume interactions to evaluate spacecraft reliability under operation of the thruster in its designing phase. In the tool, Particle-In-Cell method is adopted to solve trajectories of beam and charge exchange ions under electrostatic field self-consistently. Particle tracking method is also adopted to compute the direct interactions such as the impingements of the plume ions onto the surface of a spacecraft to reduce numerical cost. In this paper, as a first step of the development, specifications of the code are described, and the fundamental functions such as determination of the distribution of the plume, production of charge-exchange ions, and electrostatic potential are introduced. Application analysis of the tool for an actual large-scale satellite, the estimation of the generating torque toward the center of mass of the spacecraft by the impingement of the plume ions, is also shown.</p>