This paper considers the problem of determining the position of the center-of-mass and inertia tensor of a microsatellite mockup on an air-bearing testbed by using optical measurements. The position of the mockup's center of mass can be shifted relative to the suspension's center by using a system of electrodynamic linear actuators and loads fixed on them. Using the equations of motion of the mockup on an aerodynamic suspension and measurements of its angular position, the inertia tensor and center-of-mass position of the model are estimated. Based on these estimates, the linear actuators move to set the desired center-of-mass position relative to the suspension point. The developed algorithm for automatic balancing of the microsatellite mockup is experimentally investigated.