In order to extend the orbital lifetime of spacecraft operating in Very-Low Earth Orbit (VLEO), Atmosphere-Breathing Electric Propulsion (ABEP) can be employed for atmospheric drag compensation. The concept is based on the ingestion of rarefied atmospheric particles to be used as propellant for an electric thruster, thereby removing the need for onboard propellant. The present paper aims to design and analyse a passive ABEP intake optimised for the RF Helicon-based Plasma Thruster (IPT), which is selected as the most promising system due to its electrodeless design, as it removes the issue of thruster corrosion, and reduced susceptibility to atmospheric variations. This is achieved by implementing the analytical model, referred to as the Balancing Model (BM), along with its main performance parameters. The Direct Simulation Monte Carlo (DSMC) solver dsmcFoam+ is thus employed to simulate the transmission probability of cylinders and hexagonal prisms with non-zero entrance velocity, yielding a mean percentage error of 2% when compared to independent DSMC results. In addition, a novel DSMC transmittance investigation of square prisms is performed. Various design configurations are optimised for circular and hexagonal intakes based on the functional requirements of the thruster, leading to a maximum collection efficiency of 45% for a cylindrical intake with a hexagonal honeycomb. The optimal intake is hence simulated via DSMC, showing a good accuracy with the BM with or without intermolecular collisions, yielding a percentage error of 0.22% in the former case and 5.53% in the latter one. The variation of incidence flow angle, accommodation coefficient and thruster transmission probability is finally investigated, and the results are validated by the agreement shown with values retrieved from the literature.

为了延长在超低地球轨道（VLEO）中运行的航天器的轨道寿命，可以采用大气呼吸电力推进（ABEP）来补偿大气阻力。该概念基于摄入稀薄的大气颗粒，用作电动推进器的推进剂，从而消除了对机载推进剂的需求。本论文旨在设计和分析针对基于 RF Helicon 的等离子推进器 (IPT) 优化的被动 ABEP 进气口，该系统因其无电极设计而被选为最有前途的系统，因为它消除了推进器腐蚀问题，并减少了对大气变化的敏感性。这是通过实施称为平衡模型 (BM) 的分析模型及其主要性能参数来实现的。因此，直接模拟蒙特卡罗 (DSMC) 求解器 dsmcFoam+ 用于模拟具有非零入口速度的圆柱体和六角棱镜的传输概率，与独立的 DSMC 结果相比，产生的平均百分比误差为 2%。此外，还进行了方形棱镜的新型 DSMC 透射率研究。根据推进器的功能要求，针对圆形和六角形进气口优化了各种设计配置，使带有六角形蜂窝的圆柱形进气口的最大收集效率达到 45%。因此，通过 DSMC 模拟了最佳摄入量，无论有无分子间碰撞，BM 都显示出良好的准确度，在前一种情况下产生 0.22% 的百分比误差，在后一种情况下产生 5.53% 的百分比误差。入射流角的变化，