A Hybrid Orbital Configuration to Address GDC Science Objectives

The Global Dynamics Constellation (GDC) mission aims to further our understanding of the processes that govern the dynamics of the Earth's upper atmospheric envelope that surrounds and protects the planet. This project aims to investigate various orbital configurations for GDC’s six satellites in order to compare and contrast the strengths and weaknesses of each configuration for addressing GDC science objectives. In particular, this study focuses on the variations in density and temperature of ions and neutrals in the thermosphere-ionosphere (IT) environment during geomagnetic storms. To achieve this, we simulate the global IT system using the Global Ionosphere-Thermosphere Model (GITM) for the March 17, 2013, geomagnetic storm event, extracting Ion and neutral data along virtual satellite orbits. Neutral temperature was investigated along two different orbital configurations –string of pearls versus longitudinal distribution of probes, it was found that the string of pearls is optimal for the study of IT evolution, but limited in coverage of the global IT system. On the other hand, the longitudinal distribution of the satellites would provide daily coverage of the global IT system. Notably, separating the satellites for 15 minutes or less in both configurations caused an increase in inter-satellite correlation, thus reducing scientific return. In conclusion, our analyses indicate that the GDC science objectives can be best addressed by a combination of the above two configurations. The “hybrid” configuration will consist of at least two of the six satellites placed in the same orbit, while the other four satellites distributed longitudinally provide global coverage of the IT system. Future investigation will focus on further verifying our conclusion by quantitatively comparing the extent to which each orbital configuration addresses the GDC science objectives.