Near-Earth Asteroid Capture via Using Lunar Flyby plus Earth Aerobraking

Capturing Near-Earth Asteroids (NEAs) in the Earth-Moon system is a potential method of future space exploration and resource utilization. In order to make the captured NEA easily rendezvoused by spacecrafts, it is expected to capture the asteroid in a low-energy and low-inclination orbit. Lunar flyby and Earth aerobraking have been proved to be effective energy-saving methods in asteroid retrieval missions. Based on the Earth aerobraking capture strategy, if a lunar flyby process is performed before the asteroid enters the atmosphere, the thermal ablation of the asteroid in the atmosphere is expected to be alleviated. This paper proposes a lunar flyby plus Earth aerobraking method to capture an NEA. Using Geostationary Transfer Orbit (GTO) as the target orbit, the efficiency of three different capture strategies (direct capture strategy, Earth aerobraking capture strategy and lunar flyby plus Earth aerobraking capture strategy) are compared. Compared to the Earth aerobraking capture strategy, simulation results show that the main advantage of the lunar flyby plus Earth aerobraking capture strategy is that the mass loss ratio can be reduced (15 real asteroids are used as examples and mass loss ratio can be reduced by 0.98–3.39%). For example, for an asteroid with a diameter of 5 m, the mass is about 170.17 tons (with a density of 2.6g/cm3), reducing the mass loss ratio by 1% means that 1701.7 kg of the asteroid materials can be saved. Meanwhile, if the asteroid has a suitable phase for lunar flyby, while reducing the mass loss ratio, the fuel consumption can also be reduced. Furthermore, the conditions that do not require maneuvering between the lunar flyby and Earth aerobraking are preliminarily discussed. During the preliminary design stage of asteroid retrieval missions, compared with the Earth aerobraking capture strategy, lunar flyby plus Earth aerobraking capture strategy provides a potentially effective option for reducing the mass loss and the fuel consumption.

Modeling and Simulation of Asteroid Capture Using a Deformable Membrane Capture Device

The National Aeronautics and Space Administration have recently been investigating a mission concept known as the Asteroid Redirect Mission, aimed at collecting a large amount of asteroid material and transporting it into lunar orbit for inspection by human astronauts. Of the two mission options that have been considered, one involves the capture of an entire near-Earth asteroid in the 10-m class by a robotic spacecraft. The spacecraft would first make contact with the asteroid through a deformable membrane, before securing it inside a large flexible bagging mechanism. In this paper we describe the development and implementation of a model designed for simulation of the capture process, which includes a low-complexity representation of the interaction dynamics.