Three-dimensional charging effects

The physics of three dimensional spacecraft charging is reviewed. The asymmetric plasma sheath created around a spacecraft can significantly alter the trajectories of incoming particles or repel secondary particles emitted from the surface back to the surface. Thus seemingly anomolous potential variations can be encountered. Depending on the sensitivities of the spacecraft and its instruments to such variations, charging can jeopardize mission performance or even mission life through enhanced arcing. Three dimensional interactions between the Space Station and the ambient plasma and magnetic field are increasingly important.