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Space traffic management in a congested Low Earth Orbit (LEO) environment requires an understanding of all the forces influencing a body’s motion to enable essential precise orbit prediction and determination capabilities. Among these forces, satellite aerodynamics represents a significant source of uncertainty. A neglected aspect of the satellite aerodynamics problem is the charged aerodynamic interaction of LEO objects with the ionosphere, i.e. ionospheric aerodynamics. To improve our understanding of ionospheric aerodynamics, this work numerically reproduces early experimental measurements by Knechtel and Pitts [1] of the ratio of charged to neutral drag (FD,C /FD,N) on spherical test models in a streaming Hg plasma using the Particle-in-Cell/Direct Simulation Monte Carl code, pdFOAM. Results demonstrate that pdFOAM is able to reproduce experimental trends in FD,C /FD,N with body surface potential (φB) and model radii (rB). Numerical observations indicate that, for the cases considered, direct drag forces (from ion/surface collisions) represented the primary source of the increase in FD,C /FD,N with decreasing sphere radii. The relative increase in indirect drag forces (from non-colliding deflected ions) with decreasing radii was observed to become significant when the plasma scaling parameter α (energy ratio) was greater than 0.5. These trends appear to be caused by changes in relative sheath thickness as predicted by the plasma scaling parameter χ (shielding ratio). α and χ are both scaled by φB however, making it difficult to conclusively link underlying physical phenomena with observed FD,C /FD,N trends with φB. A key recommendation for future experiments is to independently study the influence of these parameters on ionospheric aerodynamics.Space traffic management in a congested Low Earth Orbit (LEO) environment requires an understanding of all the forces influencing a body’s motion to enable essential precise orbit prediction and determination capabilities. Among these forces, satellite aerodynamics represents a significant source of uncertainty. A neglected aspect of the satellite aerodynamics problem is the charged aerodynamic interaction of LEO objects with the ionosphere, i.e. ionospheric aerodynamics. To improve our understanding of ionospheric aerodynamics, this work numerically reproduces early experimental measurements by Knechtel and Pitts [1] of the ratio of charged to neutral drag (FD,C /FD,N) on spherical test models in a streaming Hg plasma using the Particle-in-Cell/Direct Simulation Monte Carl code, pdFOAM. Results demonstrate that pdFOAM is able to reproduce experimental trends in FD,C /FD,N with body surface potential (φB) and model radii (rB). Numerical observations indicate that, for the cases considered, direct drag for... |
