Satellite Drag Analysis During the May 2024 Gannon Geomagnetic Storm (2406.08617v2)

Abstract: Between May 10-12, 2024, Earth saw its largest geomagnetic storm in over 20 years. Since the last major storm in 2003, the population of satellites in low Earth orbit has surged following the commercialization of space services and the ongoing establishment of proliferated LEO constellations. In this note, we investigate the various impacts of the geomagnetic storm on satellite operations. A forecast performance assessment of the geomagnetic index ap shows that the magnitude and duration of the storm were poorly predicted, even one day in advance. Total mass density enhancements in the thermosphere are identified by tracking satellite drag decay characteristics. A history of two-line element (TLE) data from the entire NORAD catalog in LEO is used to observe large-scale trends. Better understanding how geomagnetic storms impact satellite operations is critical for maintaining satellite safety and ensuring long-term robust sustainability in LEO.

• The paper reveals that persistence-based forecasts significantly underpredicted the storm’s satellite drag by inadequately estimating the ap index.
• The study validates the NRLMSISE-00 model by showing strong correlations between increased atmospheric density at 400 km and observed orbital decay.
• The paper demonstrates that enhanced drag forced swift orbit-raising maneuvers for LEO satellites, complicating conjunction assessments and debris mitigation.

Satellite Drag Analysis During the May 2024 Gannon Geomagnetic Storm: A Synopsis

This paper offers a detailed examination of the impact of the May 2024 Gannon geomagnetic storm on satellite dynamics in low Earth orbit (LEO). It addresses an essential aspect of satellite management under geomagnetically disturbed conditions, providing both empirical data analysis and theoretical insights into how such events affect satellite drag, atmospheric density, and orbital decay.

The research opens by contextualizing the event, noting that the May 2024 geomagnetic storm was the most intense in over two decades, heavily impacting the significantly increased satellite population since the last major event in 2003. The paper marks a distinct increase in satellite operations, driven by commercial constellations, which necessitates improved understanding and mitigation strategies for satellite safety and sustainability.

Key Findings

1. Forecast Performance Issues: The paper highlights inadequacies in forecasting geomagnetic indices, particularly the $ap$ index during the storm. Despite being instrumental in predicting satellite drag and future orbital positions, the one to three-day forecasts underpredicted the storm's intensity, suggesting reliance on persistence-based methodologies that fail in rapidly changing conditions.
2. Thermospheric Density Modeling: Utilizing the NRLMSISE-00 model, the study illustrates significant increases in atmospheric mass density at 400 km altitude, coinciding with geomagnetic activity peaks. This model, though empirical, aligns well with observed orbital decay, proving crucial for satellite trajectory predictions under storm conditions.
3. Satellites' Dynamical Response: The enhanced atmospheric drag significantly affected satellite operations, with nuanced analysis of Two-Line Element (TLE) data revealing increased decay rates for many LEO satellites. Notably, operators were forced to execute swift orbit-raising maneuvers, especially concerning large constellations like Starlink.
4. Conjunction Assessment Challenges: This paper brings to light the challenges for satellite conjunction assessment due to poor state propagation resulting from inaccurate drag forecasts and rapid frequency of unplanned maneuvering. The cascading effect on conjunction prediction pipelines necessitates rapid state update capabilities and improved space weather forecasting to sustain collision avoidance strategies.
5. Geomagnetic Storms as Debris Mitigation Mechanisms: Interestingly, the paper provides evidence to suggest that geomagnetic storms accelerate orbital debris decay. While increased atmospheric density negatively impacts satellites requiring station-keeping maneuvers, it simultaneously aids in reducing the orbital debris population, underscoring storms' dualistic impact on LEO environment sustainability.

Implications and Future Directions

This investigation posits significant implications for both satellite operations and theoretical modeling of atmospheric interactions. Practically, the findings suggest that improved forecasting models are necessary to account for rapid changes during geomagnetic events, which would bolster predictive accuracy in satellite orbit tracking and collision avoidance systems. Theoretically, the paper reinforces the necessity to integrate complex atmospheric modeling into real-time applications, advancing both computational tools and observational techniques.

The paper also stimulates considerations on operational protocols for satellite constellations, urging development not limited to automated station-keeping but also encompassing preemptive mitigation strategies for handling enhanced drag scenarios during severe space weather events.

Future research may focus on enhancing model fidelity for forecasting geomagnetic storms, leveraging machine learning or augmenting data assimilation techniques. Furthermore, investigating the interplay between geomagnetic storms and smaller-sized debris populations in greater detail could provide additional avenues for ensuring long-term operability and safety within LEO.

In conclusion, this paper makes instrumental contributions to our understanding of satellite-sustainable operations during geomagnetic storms, urging the global satellite community to adapt and refine current practices in anticipation of such natural perturbations.