Ricerc@Sapienza

In this paper, the feasibility of exploiting the Sun’s gravitational force to design the final
phase (capture and orbit circularisation) to Mercury with a low propellant consumption has
been investigated. The initial conditions, on the eccentricity and argument of pericentre, for
the circularisation phase are obtained from a prime integral of motion, which takes place
when the probe moves over a polar orbit. A numerical analysis has highlighted how these
initial conditions allow, under the third-body effect, an optimal reduction of eccentricity

Low-energy trajectories take advantage of the mutual action of multiple celestial bodies on the spacecraft, and can conclude with ballistic capture about the arrival body, thus allowing significant savings in terms of propellant consumption, if compared to more traditional transfers. Because of the chaotic nature of multibody environments, the design of low-energy trajectories with given constraints can be complex and it is often obtained after a long, iterative, and eventually computationally expensive process.

This research aims at ascertaining the existence and characteristics of natural long-term capture orbits around a celestial body of potential interest. The problem is investigated in the dynamical framework of the three-dimensional circular restricted three-body problem. Previous numerical work on two-dimensional trajectories provided numerical evidence of Conley’s theorem, proving that long-term capture orbits are topologically located near trajectories asymptotic to periodic libration point orbits. This work intends to extend the previous investigations to three-dimensional paths.