Trigger mechanism for an electrostatic discharge on Relay 2

Ascertain the specific trigger that could have produced an electrostatic discharge on the defunct Relay 2 satellite at the time of the observed nanosecond radio burst, noting the low geomagnetic activity and sub–Van Allen belt altitude.

Background

The authors consider electrostatic discharge (ESD) a plausible origin for the observed burst, drawing parallels to arc-induced radio emission observed from GPS satellites and laboratory experiments. However, given the calm geomagnetic conditions (global Kp index of 1) and Relay 2’s altitude at the time of the event, they were unable to identify any specific environmental or operational trigger for an ESD.