The connection between solar drivers and the Earth���s magnetosphere, ionosphere, and thermosphere (MIT) phenomena in the upper atmosphere is very complex and dependent on many processes, including energy-absorption, ionization, and dissociation of molecules due to variable X-ray and Extreme Ultra Violet (EUV) solar radiance. Moreover, the variable solar wind plasma combined with a favorable alignment of the Interplanetary Magnetic Field (IMF) can produce auroral particle precipitation at high latitudes, causing chemical reactions and enhanced Joule heating through collisions between electrically-charged and neutral particles. Consequences of upper-atmosphere conditions on human activity underscore the necessity to better understand and predict the effects of MIT processes and coupling, and prevent from potential detrimental impacts on orbiting, aerial, and ground-based technologies. The spatial gradients of charged particles (mostly free-moving electrons in the ionosphere) can perturb the propagation of electromagnetic radio waves employed by satellite communication systems, remote sensing imaging, and Global Navigation Systems (GNSS) measurements. The upper atmospheric expansion/contraction in response to the variable solar and geomagnetic activity produces the variable aerodynamic drag on low Earth orbiting (LEO) satellites, which makes the satellite tracking difficult, decelerates LEO orbits, reduces their altitude, and shortens the lifespan of space assets. The exponential increase in space debris (including the recent destructive events of Fengyun-1C, Iridium, and Mission Shakti) also highlights the importance of orbital tracking for the prediction and avoidance of potential collisions with orbiting satellites by space debris. Finally, ground pipelines, power grids, and electronics could be influenced by the sudden changes in the magnetic field and associated current system caused by interplanetary shocks. Unfortunately, the MIT coupling and its resulting MIT variations under different space weather conditions are still not well understood, and the existing models are incapable of predicting the MIT variability as required, in spite of the efforts to model variations, anomalies, and climatology over the last half-century. This is largely due to the lack of comprehensive approaches for calibrating the models, and the limited quantity of both observations under various conditions in both hemispheres, and comprehensive and coordinated observations of auroral particle precipitation and ion drift / field-aligned current. Our research aims to improve the understanding of the MIT coupling and its resulting MIT variations under various solar forcing conditions. In addition, waves from the lower atmosphere including atmospheric tides and planetary waves can feed into ionospheric electrodynamics, and consequently to the MIT system. Gravity waves can deposit momentum in the MIT, and change the mean state which then influences the wave propagation of larger waves. To that end, our tasks are to exploit the knowledge of the MIT processes by examining multiple types of magnetosphere, ionosphere, and thermosphere observations. The final outcome will help to enhance the predictive capability of empirical and physics-based models through interrelating and exploring dependencies of variability between essential geodetic variables.