Efficient disposal of low lunar orbiters on the lunar surface

Realistic numerical simulations are conducted to explore safe and efficient strategies for End-of-Life lunar spacecraft disposal on the lunar surface. Disposal from three different near-polar, low-altitude, and near-circular orbit types was analyzed to determine if impact locations that minimize the risk to protected regions of the lunar surface can be achieved consistently for low fuel costs using the Moon’s non-spherical gravity field. A total of 300,000 objects were propagated following retrograde disposal burns using a high-fidelity lunar trajectory model, and the disposal burn locations and magnitudes were compared against the resulting likelihoods of decay and lunar surface impact locations. The results identified disposal strategies that could achieve impact in safe locations for 10 m/s of $\Delta V$ or less for all orbit types, much lower than the $\Delta V$ cost to lower the perilune entirely to the lunar surface. A similar simulation-based methodology could be applied to operational lunar satellites to identify disposal strategies based on specific mission conditions. The results of this study support the development of safe and efficient End-of-Life disposal strategies that minimize the accumulation of debris in lunar orbit and extend the operational lifetimes of lunar missions.