Contaminated Sweeping Langmuir Probes Onboard Small Satellites

Langmuir probes are frequently implemented on sounding rockets and satellites to study small-scale structures and turbulent layers in Earth's ionosphere. As the CEDAR community and others transition to low-cost and low-power satellite platforms, however, it becomes increasingly important to understand the behavior of Langmuir Probes onboard satellites with minimal conductive surface area. In order for these small satellites to resolve small-scale ($<$ 10 meter) plasma density and temperature fluctuations, Sweeping Langmuir Probes (SLPs) must operate at frequencies in the kHz range. High frequency sweep rates have proven favorable for SLPs with surface contamination, and it is thought that large enough frequencies will fully bypass any contamination effects. However, this is often not the case, and the low surface area ratio produces additional dynamic charging effects in SLP data. These combined challenges necessitate a further understanding and post processing algorithm that can account for both high frequency contamination effects and dynamic charging complexities. This work presents simulations for a CubeSat in Earth's ionosphere with both a Floating Potential Probe and a Sweeping Langmuir Probe onboard. Their behavior in the presence of surface contamination is investigated, and further, the effects of the sweep profile and the equivalent circuit parameters in the contamination layer are addressed.