Challenging space missions include those at very low altitudes, where the atmosphere is source of aerodynamic drag on the spacecraft. To extend the lifetime of such missions, an efficient propulsion system is required. One solution is Atmosphere-Breathing Electric Propulsion (ABEP) that collects atmospheric particles to be used as propellant for an electric thruster. The system would minimize the requirement of limited propellant availability and can also be applied to any planetary body with atmosphere, enabling new missions at low altitude ranges for longer times. IRS is developing, within the H2020 DISCOVERER project, an intake and a thruster for an ABEP system. The article describes the design and simulation of the intake, optimized to feed the radio frequency (RF) Helicon-based plasma thruster developed at IRS. The article deals in particular with the design of intakes based on diffuse and specular reflecting materials, which are analysed by the PICLas DSMC-PIC tool. Orbital altitudes $h=150-\text{250}\text{km}$ and the respective species based on the NRLMSISE-00 model (O, ${\mathrm{N}}_2$, ${\mathrm{O}}_2$, He, Ar, H, N) are investigated for several concepts based on fully diffuse and specular scattering, including hybrid designs. The major focus has been on the intake efficiency defined as ${\eta }_c={\dot{N}}_{out}∕{\dot{N}}_{in}$, with ${\dot{N}}_{in}$ the incoming particle flux, and ${\dot{N}}_{out}$ the one collected by the intake. Finally, two concepts are selected and presented providing the best expected performance for the operation with the selected thruster. The first one is based on fully diffuse accommodation yielding to ${\eta }_c<0.46$ and the second one based on fully specular accommodation yielding to ${\eta }_c<0.94$. Finally, also the influence of misalignment with the flow is analysed, highlighting a strong dependence of ${\eta }_c$ in the diffuse-based intake while, for the specular-based intake, this is much lower finally leading to a more resilient design while also relaxing requirements of pointing accuracy for the spacecraft.

具有挑战性的太空任务包括那些在非常低的高度，大气是航天器气动阻力的来源。为了延长此类任务的寿命，需要高效的推进系统。一种解决方案是大气呼吸电推进 (ABEP)，它收集大气粒子以用作电动推进器的推进剂。该系统将最大限度地减少对有限推进剂可用性的要求，也可以应用于任何有大气层的行星体，从而使新任务能够在低空范围内进行更长时间。IRS 正在 H2020 DISCOVERER 项目中为 ABEP 系统开发进气口和推进器。这篇文章描述了进气口的设计和模拟，经过优化以供给 IRS 开发的基于射频 (RF) Helicon 的等离子体推进器。本文特别讨论了基于漫反射和镜面反射材料的进气口设计，PICLas DSMC-PIC 工具对其进行了分析。轨道高度$H=150-\text{250}\text{公里}$ 以及基于 NRLMSISE-00 模型（O， ${\mathrm{N}}_2$, ${\mathrm{哦}}_2$, He, Ar, H, N) 研究了基于完全漫反射和镜面散射的几个概念，包括混合设计。主要关注点是定义为的进气效率${\eta }_C={\dot{N}}_{○你吨}∕{\dot{N}}_{\mathrm{一世}n}$， 和 ${\dot{N}}_{\mathrm{一世}n}$ 传入粒子通量，和 ${\dot{N}}_{○你吨}$由入口收集的那个。最后，选择并介绍了两个概念，为所选推进器的操作提供最佳预期性能。第一个基于完全扩散的调节，屈服于${\eta }_C<0.46$ 第二个基于完全镜面调节屈服于 ${\eta }_C<0.94$. 最后，还分析了与流动错位的影响，强调了对${\eta }_C$ 在基于漫射的进气口中，对于基于镜面的进气口，这要低得多，最终导致更具弹性的设计，同时也放宽了对航天器指向精度的要求。