Aero-assist Technology In Manned Mars Exploration Mission

As the space technology continuously evolves and space exploration deepens,manned Mars exploration has become a hot spot of research in aerospace field.Due to its complexity and danger,manned Mars exploration produces a lot of challenges for current technologies,such as how to reduce propellant mass and increase payload mass,and how to bring astronauts back to Earth in case of mission failure.Therefore new technologies would be crucial for a successful mission and aero-assist technology is one of these new technologies,due to its potential to greatly enhance the mission.Using the manned Mars exploration as the backdrop of this dissertation,two crucial aesro-assist technologies are investigated,i.e.,aerocapture and aero-gravity assist.The research on aerocapture technology first discusses the basic idea of aerocapture,the associated advantages over traditional capture technology,and multiple constraints during the aerocapture phase.The guidance algorithms for Analytical Predictor-Corrector(APC)and Terminal Point Control(TPC)are then deduced.Based on manned Mars exploration,simulations for aerocapture technology are carried out.The results show that aerocapture can significantly increase the payload mass of the mission in different scenarios;Those two algorithms can accurately and reliably guide the aerocapture process while satisfy the heat flux constraint,total heat load constraint and g-load constraint,in the presence of multiple uncertainties.The research on aero-gravity assist(AGA)technology focuses on its application in the design of free return trajectories.The relevant concepts about free return trajectories are introduced first,and then it's proposed that AGA technology be used in the design of free return trajectories,because of the inherent shortcoming of gravity assist.The computaion models for trajectory design are introduced and a three-phase atmospheric flight model are proposed,in which the atmospheric flight is divided into descent phase,level flight phase and ascent phase,and is described by atmospheric flight angle and flight path angle.Mars free return trajectories are used as an example and "Earth-Mars-Earth","Earth-Mars-Venus-Earth","Earth-Venus-Mars-Earth" sequences are examined,in which the benefits of AGA technology on flight time,fuel consumption and hyperbolic excess velocity are investigated.The results show that the three-phase model can accurately describe the AGA maneuver and AGA technology can greatly enhance the performance of free return trajectories in terms of departure and arrival flight time and fuel consumption,etc.The results of this research show that aero-assist technologies like aerocapture and AGA have great advantages over current technologies and they are of great significance for future manned Mars exploration missions.