Combinations of Low Energy Trajectories for a Lunar L2 mission

Abstract

Measurements in the frequency range below 30 MHz, key to a better understanding of the origins of our universe, are one of the last unexplored areas of radio astronomy. Low frequency measurements suffer greatly from disturbance from man-made signals. Therefore, satellite missions are proposed which use the Moon as a shield from these disturbances, by making use of the Earth-Moon L2 Lagrange point. Such missions require large numbers of small satellites. One of the challenges for these missions is getting the satellites into their destination orbit with a very small Delta V budget. This research looks into the use of low energy trajectories for such a mission transfer trajectory.
Low energy trajectories are found on the invariant manifolds of the CR3BP and may be classified into several categories. Different combinations of these categories lead to different types of transfer trajectories. Four possible combinations were considered in this research, and compared to see which one best suits a small satellite mission to the Earth-Moon L2 Lagrange point. One combination has been previously researched in literature, the other three are new options for a transfer to the Earth-Moon L2.
The approach known from literature resulted in transfers with a required Delta V of down to 28 m/s. Using one of the other approaches, this could be reduced to 9 m/s. Additionally, one of the approaches allows for a station-keeping orbit around the Sun-Earth L2 point, which does not only make scheduling of the transfer easier, but also allows for additional mission objectives. These are encouraging results, showing that possibilities exist for the use of low energy trajectories for a lunar L2 mission.