This handbook describes spacecraft grounding architecture options at the system level. Implementation of good electrical grounding architecture is an important part of overall mission success for spacecraft. The primary objective of proper grounding architecture is to aid in the minimization of electromagnetic interference (EMI) and unwanted interaction between various spacecraft electronic components and/or subsystems. Success results in electromagnetic compatibility (EMC). This handbook emphasizes that spacecraft grounding architecture is a system design issue, and all hardware elements must comply with the architecture established by the overall system design. A further major emphasis is that grounding architecture must be established during the early conceptual design stages (before subsystem hardware decisions are made). The preliminary design review (PDR) time is too late. NASA Endorsed. OCE.