ECSS-E-ST-20-07C is the European Cooperation for Space Standardization document that establishes the electromagnetic compatibility requirements and tests for space systems, and it applies to the spacecraft, its payload and the equipment installed in it. Space presents a set of conditions that terrestrial standards do not cover. There is no supply network to disturb and no earth to return current to, so a satellite behaves as a small floating structure in which every unit shares the same reference and in which the natural capacitance to the environment is negligible; the available power is strictly limited and the harness is short and often closely bundled, so conducted and radiated coupling between assemblies is intense; and once the vehicle is launched nothing can be repaired, which places the whole emphasis on verification before launch. The standard addresses emission and susceptibility on power and signal interfaces, the grounding and bonding architecture of the spacecraft, the shielding of units and harnesses, and the specific environment created by the plasma of the ionosphere and by electrostatic charging.