EMI coupling to command lines due to solar array switching strings in spacecraft

The satellite as a system consists of various bundles of harness interconnections between subsystems, across the panels. These bundles of harness consist of different types of cables - power lines, data lines, command lines. Power lines from solar array also carry switching currents from the solar array switching circuits. When all these cables are bundled together, it essentially brings out the problem of unintentional electromagnetic energy coupling between the wires. This paper analyzes the amount of coupling in a typical command line placed in close proximity to the power lines carrying switching currents. It is reported that few in-orbit spacecraft on-board anomalies are attributed to spurious commanding due to cable coupling between the command lines and the switching power lines. This analysis considers the different harness configurations of the power lines where such possibilities exist.