International institutions have increasingly recognised that the unregulated use of near-Earth space threatens its long-term sustainability. The increase in launch activities, combined with the accumulation of uncontrolled objects, poses a significant risk to the current and future exploration of space. Meanwhile, traffic in the cislunar environment is expected to grow. The cislunar region offers major scientific and technological opportunities, but it is also characterised by a strong nonlinear dynamics driven by the coupled Earth-Moon (EM) gravitational influence. To prevent a debris problem in cislunar space, it is essential to implement a space situational awareness framework together with carefully planned, low-cost End-of-Life (EoL) disposal solutions. In this paper, EoL design is parametrised with respect to variables that could play a dominant role in the disposal dynamics, with the aim of identifying the aspects that determine low-cost and robust disposal options. We propose to study the dynamics of spacecraft departing for their EoL phase from two Near-Rectilinear Halo Orbits (NRHOs) in the EM system: one in EM-L1 and one in EM-L2. These orbits have been selected as a reference for the analysis due to their particular relevance to future missions. By following Unstable Manifold (UM) trajectories in the coupled Circular Restricted Three Body Problem (CR3BP) and carefully tuning the system’s governing parameters, all four of the disposal options which can be adopted in cislunar space can be achieved: no-return heliocentric escape, controlled lunar impact, Earth re-entry and graveyard orbit insertion. These parameters include, for example, the phase angle identifying the initial satellite location and the relative position between the EM and Sun-Earth (SE) systems at departure. The analysis then focuses on three of the four disposal options mentioned above, namely heliocentric disposal, lunar impact, and Earth re-entry. All three can be achieved with manoeuvrer costs on the order of 50 m/s and transfer times ranging from days to months, provided that specific dynamical parameters are carefully selected. Furthermore, for both the heliocentric disposal and lunar impact options, solutions involving limited corrective manoeuvrers, rather than relying solely on the natural dynamics of the system, are also proposed in order to mitigate some of the limitations associated with disposal options based solely on the transfers natural dynamics. The outcomes of this analysis are key settings that enable operators to define the appropriate initial conditions for a desired EoL scenario. Ultimately, one of the cases studied is analysed also in an ephemeris-based dynamical model, preliminary showing how the results obtained using the approximated dynamics relate to those found considering a more realistic approach.
Dynamics-driven End-of-Life Disposal Trajectories for Spacecraft Operating in Cislunar Space
Elisa Maria Alessi;
2026
Abstract
International institutions have increasingly recognised that the unregulated use of near-Earth space threatens its long-term sustainability. The increase in launch activities, combined with the accumulation of uncontrolled objects, poses a significant risk to the current and future exploration of space. Meanwhile, traffic in the cislunar environment is expected to grow. The cislunar region offers major scientific and technological opportunities, but it is also characterised by a strong nonlinear dynamics driven by the coupled Earth-Moon (EM) gravitational influence. To prevent a debris problem in cislunar space, it is essential to implement a space situational awareness framework together with carefully planned, low-cost End-of-Life (EoL) disposal solutions. In this paper, EoL design is parametrised with respect to variables that could play a dominant role in the disposal dynamics, with the aim of identifying the aspects that determine low-cost and robust disposal options. We propose to study the dynamics of spacecraft departing for their EoL phase from two Near-Rectilinear Halo Orbits (NRHOs) in the EM system: one in EM-L1 and one in EM-L2. These orbits have been selected as a reference for the analysis due to their particular relevance to future missions. By following Unstable Manifold (UM) trajectories in the coupled Circular Restricted Three Body Problem (CR3BP) and carefully tuning the system’s governing parameters, all four of the disposal options which can be adopted in cislunar space can be achieved: no-return heliocentric escape, controlled lunar impact, Earth re-entry and graveyard orbit insertion. These parameters include, for example, the phase angle identifying the initial satellite location and the relative position between the EM and Sun-Earth (SE) systems at departure. The analysis then focuses on three of the four disposal options mentioned above, namely heliocentric disposal, lunar impact, and Earth re-entry. All three can be achieved with manoeuvrer costs on the order of 50 m/s and transfer times ranging from days to months, provided that specific dynamical parameters are carefully selected. Furthermore, for both the heliocentric disposal and lunar impact options, solutions involving limited corrective manoeuvrers, rather than relying solely on the natural dynamics of the system, are also proposed in order to mitigate some of the limitations associated with disposal options based solely on the transfers natural dynamics. The outcomes of this analysis are key settings that enable operators to define the appropriate initial conditions for a desired EoL scenario. Ultimately, one of the cases studied is analysed also in an ephemeris-based dynamical model, preliminary showing how the results obtained using the approximated dynamics relate to those found considering a more realistic approach.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
