Browsing by Author "Mohamed Ibrahim"

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    Developing a modelling environment of spacecraft solar array in low Earth orbit using real-time telemetry data
    (Elsevier B.V., 2025-05-08) Ahmed Mokhtar; Mohamed Ibrahim; Mohamed E. Hanafy; Fawzy H. Amer ElTohamy; Yehia Z. Elhalwagy
    Spacecraft solar arrays convert sunlight into electrical energy to fulfil the energy requirements of various missions. This work proposes a comprehensive environment for accurate power operation predictions. Specifically, this environment simulates the behaviour of a body-mounted solar array. Furthermore, the designing and modelling processes of the solar array require considering different technical and practical constraints posed by the space environment. These challenges necessitate a thorough evaluation of all potential sources of losses and degradation. Compared to conventional approaches, our novel SSA model incorporates the complete spacecraft mission design scenario, thus it incorporates the operational cyclogram and power budget calculation. To substantiate our proposed method, telemetry data from the commercial LEOS-50 platform is leveraged to develop an experimental, mathematical, and thermal in-orbit model based on GaAs technology. This approach stands out for its exceptional accuracy in predicting the output power characteristics of solar panels. Therefore, it ensures achieving mission requirements from inception to completion in the beginning-of-life and end-of-life stages. The results demonstrate the success of the SSA operation in converting sunlight into electrical energy with a high conversion rate. © 2025 The Authors
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    MILP-MPC for planned maneuver station-keeping and collision avoidance of GEO satellites using on-off chemical thrusters
    (Ain Shams University, 2024-11-02) Mohamed Karim; Mohamed Ibrahim; Hosam Hendy; Mahmoud Ashry; Yehia Z. Elhalwagy
    GEO satellites require precise station-keeping and ensuring collision avoidance to maintain their desired orbital positions and ensure uninterrupted communication services. However, maneuvering these satellites poses significant challenges due to various geophysical factors and orbital perturbations. This work proposes a model predictive control for planned maneuver station-keeping and collision avoidance of GEO satellites using south, east, and west maneuvers. These maneuvers have been achieved using on/off chemical thrusters with a short firing time. The station-keeping problem is reformulated as an optimization problem using mixed-integer linear programming. MILP-MPC formulation simultaneously considers multiple objectives and constraints such as fuel consumption, maneuver planning, and collision avoidance for mitigating collision risks. Simulation results demonstrate the effectiveness of the proposed MILP-MPC framework compared to the real-time telemetry in achieving accurate station-keeping and collision-free operation while optimizing fuel consumption. The proposed controller increases the satellite lifetime by reducing the thruster firing time.