The backflow plume from an electric thruster can lead to the accumulation of electrostatic charge on the spacecraft, leading to a negative charge. Interactions between the plume and solar wind can further influence the charge distribution, resulting in variations in spacecraft potential and interference with sensitive instruments. A 3D Particle-In-Cell (PIC) simulation tool within the Spacecraft Plasma Interaction Software (SPIS) is used to compute spacecraft charging effects from 0.067 to 1 Astronomical unit (AU). The study examines the dynamic behaviour of ambient electrons and ions, thruster electrons, and CEX-ions, as well as photoemission and secondary electrons, and solar photon flux impact on the spacecraft potential. The main finding is the demonstration that the high dominance of CEX-ions and thruster electrons helps to achieve a low and stable negative potential ranging from -2 to -6 V from 0.067 AU to 1 AU when the thruster is on, as opposed to the varying range of -5 to +9 V with the thruster off. Other findings are that the elimination of photoelectrons or secondary electrons has a comparatively greater impact on spacecraft potential when the thruster is off, as opposed to when the thruster is on. Both CEX-ions and thruster electrons significantly contribute to the mitigation and regulation of spacecraft potential towards a less negative potential in situations where photoemission or secondary electrons are absent or relatively unimportant.