Low-Energy, Low-Thrust Transfers to the Moon

The low-thrust version of the low energy transfers to the Moon exploiting the structure of the invariant manifolds associated to the Lagrange point orbits is presented in this paper. A method to systematically produce low-energy, low-thrust transfers executing ballistic lunar capture is discussed. The coupled restricted three-body problems approximation is used to deliver appropriate first guess for the subsequent optimization of the transfer trajectory within a complete four-body model using direct transcription and multiple shooting strategy. It is shown that less propellant than standard low energy transfers to the Moon is required. This paper follows previous works by the same authors aimed at integrating together knowledge coming from dynamical system theory and optimal control problems for the design of efficient low-energy, low-thrust transfers.