Comparative Study of Auroral Charging during Severe Geomagnetic Storms

As a space weather threat to spacecraft, the history of precipitating auroral electrons interacting with spacecraft in low Earth orbit (LEO) is mixed. Auroral charging has been identified as a root cause or contributor for a few anomalies and failures of satellite systems including the lockup of a microprocessor unit controlling the microwave imager instrument on a DMSP F13 spacecraft in May 1995 (Anderson and Koons, 1996) and the failure of the power system and loss of mission for the ADEOS II spacecraft in October 2003 (Kawakita et al., 2004; Maejima et al., 2004). However, extreme charging of DMSP, Freja, and Jason-3 spacecraft in polar LEO environments resulting in frame potentials of -1 kV to -3 kV have been documented without any negative impacts to the spacecraft bus or payload systems. Recent studies suggest the probability of auroral charging increases with geomagnetic activity as measured by the geomagnetic Kp index, forecasting that auroral charging could be a stronger threat to LEO spacecraft in polar orbits during severe geomagnetic storms. To test this hypothesis, we investigate the frequency of occurrence for auroral charging on DMSP spacecraft from the early 1980’s into the second quarter of 2024 during severe geomagnetic storms. The selection criteria for including geomagnetic storms in the study are storm periods for which the peak Kp and Dst indices are Kp ≥ 7 and Dst ≤ -250 nT, respectively. Many historically large geomagnetic storms are included in the study including the March and October 1989 storms, the Halloween Storms of 2003, March 2001 and November 1992 storms, and the Bastille Day Storm of 2000 among others. In addition, the recent Gannon Storm of May 2024 which reached G5 geomagnetic storm levels for the first time in nearly two decades is included in the study. We will discuss if there is credible evidence for a greater threat of auroral charging on polar orbiting LEO spacecraft during severe geomagnetic storms or if the conditions that drive the well-known solar cycle and seasonal dependence for auroral charging is more important than storm time space weather events.