Configuration optimization design method for stabilized drag ballon spacecraft: Configuration Optimization for Stabilized Drag Balloon

In the deorbiting mission using drag balloons, there are several challenges, such as the diversity of deorbiting targets, complex disturbances in Low Earth Orbit (LEO), irregular windward areas, and the coupling of windward area with attitude and configuration. These issues make it difficult to quickly obtain drag balloon configurations that meet both deorbiting time and stability requirements, leading to repetitive iterations in engineering design and low computational efficiency. This presents obstacles to establishing deorbiting standards and achieving standardized, serialized, and scalable designs. This paper proposes an optimization design method for stable drag balloon configurations. The method enables the rapid determination of drag balloon configurations for any deorbiting target, ensuring compliance with the deorbiting time constraint while maintaining good shape and attitude stabilities. Key configuration parameters include radius, lobe number, and installation offset. Firstly, a surrogate-model-based predictor with bisection corrector is developed to efficiently estimate the required self-adaptive area. Secondly, a finite-element-based method is used to compute the projected area of arbitrarily shapes, optimizing radius and lobe number while satisfying area constraints, taking into account both shape stability and cost. Finally, a nonlinear analysis identifies feasible installation offset domains by evaluating the number and stability of attitude equilibrium points. This study provides a foundation for the configuration design and practical implementation of drag balloons.