Total Ionizing Dose Observations On-Board STPSat-6 in GEO

The Falcon Solid-state Energetic Electron Detector (SEED) is an energetic charged particle sensor that has been developed at the United States Air Force Academy to monitor electron flux across the energy range of 14 to 145 keV in geosynchronous orbit (GEO). This sensor has been developed to complement ongoing efforts by the Air Force Research Laboratory (AFRL) to advance a comprehensive space environment sensor suite, Compact Environmental Anomaly Sensor (CEASE3), for anomaly resolution. The Falcon SEED instrument is designed to demonstrate the ability to develop a CubeSat compatible, low size, weight, power, and cost (SWAPC) energetic particle sensor, based on predominantly commercial off the shelf (COTS) components. The final flight payload fits within a volume of 10 cm × 10 cm × 20 cm, in a 4.3-kg, 3.4-W package. The instrument has fulfilled a one-year mission lifetime in GEO thus demonstrating that a low SWAP-C design can survive the harsh environment of space while still providing relevant science data. The instrument utilizes a single 301-μm-thick silicon solid-state detector and COTS digital pulse processor to measure detected counts as a function of deposited energy to determine the incident electron flux and a microdosimeter to monitor total ionizing dose (TID) within the electronics card cage. Analysis of the Falcon SEED instrument data provides valuable dosimetry information for the STPSat-6 payloads, along with providing comparisons to space radiation models. We present TID enhancements as a function of energetic electron and proton injections. These data provide an indication of STPSat-6 spacecraft health throughout the first year of operational life.