Non-Spherical Gravity Terms

Author: Tianjiang Shuo

Website: https://cislunarspace.cn

Definition

The part of a celestial body's gravitational field that deviates from spherical symmetry, described by higher-order terms in a spherical harmonic expansion. For DRO orbit determination in cislunar space, lunar non-spherical gravity terms affect 7-day orbit prediction accuracy by up to about 30 m and must be included in the dynamical model. Higher-order terms have smaller perturbation magnitudes.

Application Value

在轨道设计阶段，可usingThis轨道类型构建候选轨道池，为星座部署和任务轨道选择provides参考。在轨运行时，This轨道特性可used for轨道维持策略设计，降低推进剂消耗。在轨道转移规划中，其稳定流形结构可指导低能量转移走廊的搜索。

Related Concepts

• 运行轨道库（Operational Orbit Library）
• 月球自由返回轨道（Lunar Free-Return Orbit, LFO）
• 临界轨道（Critical Orbit）
• 准周期远距离逆行轨道（Quasi-Periodic Distant Retrograde Orbit, QPDRO）

References

• 黄逸丹等2024 基于地基测量数据的月球DRO轨道定轨精度分析