The Flight to Neptune and its Moons Triton and Nereid as a Demonstration of the Possibility of using Low-Thrust Engines in Missions to Giant Planets

The paper suggests a possible scenario of a flight to Neptune’s moons Triton and Nereid. At the moment, Triton and Nereid remain among the least studied moons in Solar system. A detailed study of Triton can confirm a number of theories about its origin. The study of Nereid, the third largest satellite of Neptune with the greatest eccentricity among all known moons, will help to better understand the evolution of the Neptune moon system and confirm or refute the hypothesis that Triton was captured by Neptune’s gravity and seriously destroyed the original system of its moons. A significant problem in the study of giant planets and their satellites is the lack of effective space transport systems that allow delivering a large payload over such long distances. One of the most promising solutions to this problem is the use of propulsion systems with low thrust, ensuring the implementation of the flight with minimal expenditure of the working fluid. The scenario allows a spacecraft with low-thrust engines to reach Neptune by performing two gravity assist maneuvers near Earth and one gravity assist maneuver near Jupiter. The flyby of Triton and Nereid is carried out within the framework of one mission and make possible to explore the surface of both moons from a distance of 10 thousand km. The achievement of this task is carried out by using a modern ion propulsion system with a specific impulse of 3500 s and a thrust of 0.15 N. It is shown that with an initial mass of 850 kg and a mission duration of 29 years, the total cost of the propellant will not exceed 350 kg.