The objective is to design, manufacture and test a monitor of surface charging on solar arrays to measure the surface potential at various locations of the solar array with respect to ground and so toobtain information to better match the design and verification methods of solar arrays to the needs.
Targeted Improvements: To verify how potentials develop on solar array surfaces.To understand the fraction of an array involved in the discharge process and correlate of anomalies with surface potentials.To simplify the current design if prevention is found to be over-engineered or if a dangerous frequency of potentials capable of causing damage and service interruptions can be demonstrated anddesign improvements made.To streamline the validation method and procedure totest the photovoltaic assembly against ElectroStatic Discharge (ESD) events.
Description: Spacecraft electrostatic charging can be a source of critical damage to spacecraft solar arrays in geostationary orbit. Differences in potential between the solar cell coverglass surfaces and underlyingmaterials that are linked to spacecraft ground are often the main electrostatic hazards in geostationary spacecraft. High levels of differential potentials lead locally to electrostatic discharges, whichmay then propagate across the solar array surface. The potentials of the coverglasses with respect to local ground and the portion of the solar array involved in the discharge process as well as the frequency of the discharge events have not been measured in space. In-orbit measurements are considered important for further improvement of the solar array designs and their verification withrespect to ESD.In this activity, a monitor of surface charging on solar arrays will be designed and tested. Such a device would measure the surface potential at various locations of the solar array with respect toground. The monitor shall also be able to detect any discharge events and the area of the solar array involved in the discharge event.A scaled Engineering Model of the solar array charging monitor shall be designed, manufactured and tested under simulated charging conditions on a photovoltaic assembly. The monitor shall besafe by showing it will not itself trigger discharges. The size and location of the monitor(s) as well as the test configuration shall be optimised in collaboration with array manufacturers.