This paper presents Orbita, a novel space simulation framework designed for the holistic modeling and validation of spacecraft dynamics, sensing, and control. Unlike existing approaches that decouple orbital dynamics from visual perception, Orbita integrates high-fidelity propagation, synthetic image generation, vision-based navigation, and closed-loop control into a unified softwarein-the-loop environment. To demonstrate its capabilities, a Line-of-Sight tracking problem is solved using inputs from an onboard camera. We design, implement and validate a deterministic computer vision pipeline, a modified Multiplicative Extended Kalman Filter for relative attitude estimation, and a Lyapunov-based Backstepping controller for vision-guided spacecraft pointing. A representative case study involving two CubeSats in close-proximity operations is considered, assessing the effect of attitude perturbations on the overall system performance.