Abstract: Under hypersonic wake conditions, multi-body separation is progressively emerging as one of the ideal technical pathways for hypersonic vehicles to achieve payload deployment, owing to its significant advantages in areas such as thermal protection, shape preservation, stealth capability, and multiple deployment and recovery operations. However, a strong coupling effect exists between the complex flow field at the rear section of the vehicle and the multi-body separation process. The structure of the flow field is highly intricate, accompanied by pronounced unsteady aerodynamic effects, nonlinear behaviors, and even asymmetric phenomena, which pose substantial challenges for predicting and controlling the separation process. Focusing on the separation process under hypersonic wake conditions, the present work numerically investigates the lateral separation process through employing the overset grid technique. The investigation examines the characteristics of variations in aerodynamic forces and the thermal environment experienced by the separating body as it moves within the recirculation zone and regions beyond it. The current findings reveal that when the separating body moves from the recirculation zone into the expansion wave region, a shock wave is generated on its lower surface due to the supersonic airflow, resulting in a significant localized increase in heat flux. In contrast, when separation occurs downstream of the reattachment shock wave, far from the recirculation zone, the lift and drag coefficients on the surface of the separating body exhibit considerable fluctuations. These fluctuations greatly increase the difficulty of maintaining attitude control. In addition, during its movement, the separating body experiences a continuous increase in pitch angle, manifesting a distinct "nose-down" tendency. This phenomenon is found to be more pronounced when separation occurs in the far-field. The numerical results in the present work can provide a theoretical foundation and serve as a reference for developing control strategies in the engineering design of hypersonic wake separation schemes.