Calibration of the SPORT Langmuir and Electric Field Probes and SPICE Modeling

Abstract:

Utah State University has developed a miniaturized suite of basic space weather instrumentation for ionospheric density, temperature, and electric fields. These observations are provided by a Sweeping Langmuir Probe and an Electric Field Probe. In this paper we present the functionality, performance, and testing results of these miniature, low-power CubeSat probes. The Sweeping Langmuir Probe will be used in conjunction with observations of the spacecraft floating potential by the Electric Field Probe to measure the relative electron density and temperature of the surrounding plasma. Both of these instruments have been integrated into a single 9 cm by 9 cm electronics module supported by sensors on deployable booms and will fly on the SPORT mission in the 4^th quarter of 2021. SPORT is a 6U CubeSat mission to advance the scientific understanding of the preconditions leading to equatorial plasma bubbles and is a joint Brazil and United States mission. The electric field probe will also be used to study plasma waves and irregularities associated with plasma bubbles. Utah State has developed a set of spacecraft surface changing models in the general-purpose SPICE circuit simulator to understand the interaction of these probes operating on the small surface area of the SPORT CubeSat. Within this paper we present the instrument’s predicted performance including spacecraft surface charging and coupled probes using SPICE models. We discuss both the calibration techniques and calibration results in relation to the SPICE model of the probe and spacecraft.