Alternative approach to the DART mission by the use of gravity assist maneuvers with the Moon and solar sails

<jats:title>Abstract</jats:title><jats:p>The formation of our Solar System and planetary defense strategies are among the priorities to be investigated in the next years by the space science community. As <jats:italic>in-situ</jats:italic> missions to small bodies (as comets and asteroids) are options to conduct these investigations, this paper proposes a combination of methodologies to produce low-cost transfers to near-earth asteroids (NEAs). Low-cost trajectories derived from retrograde periodic orbits around <jats:inline-formula><jats:alternatives><jats:tex-math>$${L}_{1}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>L</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:math></jats:alternatives></jats:inline-formula> are taken as a starting point for the escape of the Earth-Moon system and, as the vehicle exits the sphere of influence of Earth, the deployment of an adjustable solar sail guarantees the interception of the target in a predetermined position and time of flight. Different sail loadings (164, 61 and 30 g/m<jats:sup>2</jats:sup>) are tested and a case study to the NEA 65,803 Didymos is presented. The results show economies in the velocity increments required by the mission up to 8.48%, although a longer time of flight might be needed depending on the sail loading.</jats:p>