Speaker
Description
This exploratory study investigates the optimisation of Earth-departure inclination angle for low-energy Earth-Moon transfer in the context of Danish-led Máni mission which is in the ongoing process of Phase A/B1. Using ESA MIDAS-SALTO, the ballistic Earth-Moon flyby leg under the three body dynamics of Sun, Earth and Moon in the ICRF. Initial states are generated via SALTO Lunar-Lambert guess strategy to minimise the delta-V budget ($\Delta v$). In order to emphasise the inclination effect of the transfer, we take the range of the inclination angle between $0^\circ$ and $70^\circ$ having a step of $5^\circ$ with the constant of RAAN and argument of periapsis at $0^\circ$ and assume that the satellite has an electric propulsion with an impulsive-equivalent model. Results show two distinctive regimes, firstly, from the inclination range from $5^\circ$ to $40^\circ$ , the optimised $\Delta v$ decreases smoothly as the inclination increases having a mean of $0.447 \text{km/s}$ and slope of $-1.8\text{m/s/deg}$ indicating predictable launch-window selections. On the other hand, from $40^\circ$ to $70^\circ$, the $\Delta v$ of the transfer becomes non-monotomic and high-variance with the mean $\Delta v$ of $0.338\text{km/s}$ despite an increasing number of geometric alternatives from $100$ at $40^\circ$ to $150$ at $70^\circ$. Following this result, this gives a transition to a fully three-dimensional, Kozai-Lidov-like regime which phase-space windows increase dynamical accessibility with the increasing number of geometrical alternatives while decreasing optimisation robutness with a high-variance of the delta-V within the range between $40^\circ$ and $70^\circ$. Conclusively, this implies that more alternatives for the launch window introduce the decreasing trend of the optimisation robustness, and the $<40^\circ$ inclination regime gives us stable launch-window to balance the geometrical accessibility with the operational and optimised feasibility for the mission.