Interplanetary mission design with applications to guidance and optimal control of aero-assisted trajectories
Abstract
A method for finding optimal aerogravity-assist tours of the solar system is developed using indirect methods. Two cost functionals are used in the optimization; finding the minimum required maximum lift-to-drag ratio, with and without a convective heating-rate path constraint, and the path which provides the minimum total stagnation point convective heat load. It is found that using present or near-future thermal protection system materials will suffice for certain aerogravity assist trajectories at Mars. Minimum heat load optimal trajectories are found for aerocapture maneuvers at Uranus and Neptune. With a large radius, and short rotational periods, atmospheric rotation must be taken into account to accurately model the system dynamics. Investigation of the 2018 Inspiration Mars free-return opportunity is conducted. A broad search over 100 years of Mars free-return trajectories is catalogued, and a Pareto front analysis is employed to find the overall best trajectories in the timespan. The geometry is explored further with the use of a time-free ephemeris to see where minimal energy transfer arcs between Earth and Mars occur, and see if the 2018 opportunity is one such transfer. It turned out that both the 2017 and 2064 candidates found from the 100-year search were the closest to minimum energy, highlighting the rarity of the Inspiration Mars opportunity, and gives a motivating push to fly this mission.
Degree
Ph.D.
Advisors
Longuski, Purdue University.
Subject Area
Aerospace engineering
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