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Vision-based Spacecraft Attitude Formation Control: Relative attitude determination is a key component for multi-spacecraft missions. This research investigates a novel scheme based on vision-based sensors to control the relative attitude formation among multiple spacecraft accurately while the spacecraft are moving and deploy their missions.Research Method: Two pointing directions, referring to line-of-sight measurements, from a spacecraft to two distinct objects can determine the full attitude of singlespacecraft uniquely as long as they are not parallel to each other. Similarly, line-of-sight measurements among multiple spacecraft in formation can be applied to obtain the relative attitudes completely. A nonlinear controller is developed to track a given desired formation command. Since the relative attitude is directly expressed in terms of line-of-sight measurements, thereby avoiding needs for expensive inertial measurement units. Further, the controller is constructed in a coordinate-free fashion on the nonlinear configuration manifold directly.