  The increasingly congested near earth environment requires accurate orbital
modelling to prevent collision events that threaten access to space
infrastructure. Ionospheric aerodynamics are the largest non-conservative
source of orbital perturbations. Work done by Brown et al provided a prediction
method for drag forces on charged bodies in low earth orbit based on applying
approximations of single species flows to representative plasma simulations.
Recent work on mixed species plasma sheaths motivates investigation of this
assumption. Mixed species plasma flows over charged bodies with representative
LEO conditions were simulated, focusing on orbital motion limited O$^+$
dominated flows, and sheath limited H$^+$ dominated flows. The significance of
small concentrations of different ion species was analysed in terms of
aerodynamic effects on the body. Introduction of small concentrations of H$^+$
into a flow dominated by O$^+$ molecules showed significant disruptions to the
wake structure, coupled with an increase in drag coefficient for a satellite in
that flow. Introducing heavier O$^+$ molecules into a sheath dominated H$^+$
flow found little disruption to the wake structure. A multi-species drag model
was proposed, building on work in Brown et al. This model was found to
qualitatively describe changes in wake structure, but consistently over
predicted drag coefficients. This finding suggests that the influence of mixed
species flows on ionospheric aerodynamics involves significant contributions
from inter-species interactions not described adequately by considering the
separate species as either separate flows, or one flow with adjusted
parameters.
