AI 中文总结
研究评估用于月球南极 PNT 和地对地球中继任务的郁金香形轨道星座，与 ELFO 星座比较，分析六卫星基线和五卫星变体在特定区域的性能，其满足相关指标，航天器保持地球视线，机动成本低。
AI 中文摘要
本几何研究评估了一种紧凑的七瓣、6:5 共振郁金香形轨道星座，用于月球南极的定位、导航和授时（PNT）以及地对地球中继服务。将郁金香形轨道与椭圆月球冻结轨道（ELFO）星座在 NASA LunaNet 服务区域 2（SV2）上进行比较，该区域覆盖南纬 -75 度以南的月球纬度。比较了六卫星郁金香基线与最低成本的五卫星变体；两者使用相同的三体轨道，仅在卫星数量和沿轨道相位上有所不同。性能根据三个初始运行能力 C（IOC-C）指标进行评分：视线（LOS）链路可用性、月球增强导航系统（LANS）精度几何稀释（GDOP）低于 6，以及每日舱外活动（EVA）可用 PNT 窗口。两个郁金香星座在 SV2 上均满足所有三个 IOC-C 指标。六卫星配置大幅满足要求：最差点每日 GDOP 可用性为 75%，每日 EVA 支持时间为 18 小时。五卫星变体也通过了，但余量较小：可用性为 44%，EVA 支持时间为 10 小时。与 ELFO 配置不同，郁金香形星座中的每艘航天器都保持与地球的连续视线，为直接单跳地球中继提供持续的几何机会。由于所有航天器共享单个三体轨道，初始相位调整和故障后重构简化为相邻轨道之间的沿轨道漂移机动，筛选级估计表明机动成本较低。
英文摘要
This geometric study evaluates a compact seven-petal, 6:5-resonant tulip-shaped orbit constellation for lunar south-pole positioning, navigation, and timing (PNT) and direct-to-Earth relay services. The tulip-shaped orbits are compared against elliptical lunar frozen orbit (ELFO) constellations over the NASA LunaNet Service Volume 2 (SV2), covering lunar latitudes south of -75 degrees. We compare a six-satellite tulip baseline with a minimum-cost five-satellite variant; both use the same shared three-body orbit and differ only in satellite count and along-track phasing. Performance is scored against three Initial Operating Capability C (IOC-C) metrics: line-of-sight (LOS) link availability, Lunar Augmented Navigation System (LANS) geometric dilution of precision (GDOP) below 6, and daily extravehicular activity (EVA) usable-PNT windows. Both tulip constellations satisfy all three IOC-C metrics across SV2. The six-satellite configuration meets requirements with wide margin: 75% worst-point daily GDOP availability and 18 hours of daily EVA support. The five-satellite variant also passes, but with thinner margin: 44% availability and 10 hours of EVA support. Unlike the ELFO configurations, each spacecraft in the tulip-shaped constellation maintains continuous Earth line of sight, providing persistent geometric opportunity for direct single-hop Earth relay. Because all spacecraft share a single three-body orbit, initial phasing and post-failure reconstitution reduce to along-track drift maneuvers between neighboring orbits, with screening-level estimates indicating low maneuver cost.
Comments9 pages, 6 figures
