As international lunar exploration initiatives accelerate, the volume of spacecraft operating in cislunar space
is expected to rise substantially in the coming decade. This growth highlights the urgent need for clear and
effective end-of-life (EoL) policies for missions operating in the Earth–Moon system. In low Earth orbit (LEO),
both U.S. and European regulatory frameworks—including NASA’s safety directives, the Federal Communication Commission’s 5-year disposal requirement adopted in 2022, and the corresponding European guidelines
endorsed in 2023—now mandate de-orbiting within five years. Comparable regulatory pressure is anticipated for
higher-altitude geocentric regimes and, increasingly, for lunar orbits and cislunar trajectories, where uncontrolled
spacecraft can pose both short- and long-term hazards, including potential collisions, debris generation, surface contamination, or unanticipated Earth return due to the complex dynamical interplay in the Earth–Moon environment.
In this context, the present work aims to demonstrate and characterize how spacecrafts on libration-point and mean-motion resonance orbits can efficiently plan an end-of-life via de-orbitation and precise lunar
impact. Using the circular restricted three-body problem (CR3BP) framework, we show that the unstable
invariant manifolds naturally associated with these orbits can provide low-energy return pathways that can be
exploited to remove spacecraft from their operational trajectories. The objective is to assess if this disposal
solution is feasible for every studied case and how these solutions, characterized by the ?V and time needed
to reach the lunar surface, compare across the set.
To ensure that disposal trajectories are environmentally and programmatically acceptable, we evaluate all
candidate return paths against an updated lunar exclusion map previously introduced in our 2025 IAC publication. This map incorporates international guidelines for the protection of heritage landing sites, zones of high
scientific interest, and regions containing volatile-rich or otherwise valuable resources.
To build a representative understanding of disposal feasibility across the cislunar phase space, we selected a diverse set of 29 periodic orbits drawn from the publicly available JPL Three-Body Periodic Orbit Catalog as well as some stable and unstable mean-motion resonance (MMR) orbits currently populated: Tiandu-1 (3:1), DRO-B (3:2), IBEX (3:1), and TESS (2:1). This set encompasses a wide variety of families spanning a broad range of geometries, linear stabilities, and orbital periods.
Each orbit is uniformly sampled at a one-hour interval. For every sample point, we computed the minimum norm impulsive maneuver required to inject the spacecraft onto the corresponding branch of the unstable
manifold leading to a safe disposal trajectory, with the constraint that the complete re-entry or disposal must
occur within a three-year horizon. Across all orbits and all sampling points, the required impulsive maneuvers
span twelve orders of magnitude in ?V, demonstrating both the sensitivity of the cislunar dynamical landscape
and the abundance of naturally accessible escape pathways. Many segments of these studied orbits require very
small maneuvers, whereas others—depending on the orbital geometry or stability index—demand significantly
larger and are sometimes impossible to produce during an impulsive burn. This variability is explicitly quan-
tified, providing operators with a full spectrum of ?V options along each orbit and enabling redundancy and
flexibility in maneuver planning.
By integrating these elements—CR3BP dynamics, unstable invariant manifold-based disposal, protected-
region filtering, and comprehensive minimum ?V determination—this study provides a robust end-of-life
strategy through a systematic assessment of phase-dependent disposal accessibility maps under a fixed time
horizon for spacecraft operating in libration-point and lunar mean-motion resonance orbits in the Earth–Moon
system. This procedure allowed us to identify where disposal is feasible, infeasible, and operationally attractive
in each of the orbits covered in the set.
In addition, this framework is being proven relevant, not only for long-duration missions using near-rectilinear
halo, like the Gatewa, but also for stable resonant graveyard candidate orbits or unstable resonant bands.
By doing so, this framework supports future policy development by demonstrating that a three-year disposal
limit—shorter than existing LEO requirements—remains technically achievable for a wide variety of cislunar
missions.