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Author
Title An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion
URL
Publication Date
Date Accessioned
Degree PhD
Discipline/Department Aerospace Engineering
Degree Level doctoral
University/Publisher University of Kansas
Abstract Solar sails use the endless supply of the Sun's radiation to propel spacecraft through space. The sails use the momentum transfer from the impinging solar radiation to provide thrust to the spacecraft while expending zero fuel. Recently, the first solar sail spacecraft, or sailcraft, named IKAROS completed a successful mission to Venus and proved the concept of solar sail propulsion. Sailcraft experimental data is difficult to gather due to the large expenses of space travel, therefore, a reliable and accurate computational method is needed to make the process more efficient. Presented in this document is a new approach to simulating solar sail spacecraft trajectories. The new method provides unconditionally stable numerical solutions for trajectory propagation and includes an improved physical description over other methods. The unconditional stability of the new method means that a unique numerical solution is always determined. The improved physical description of the trajectory provides a numerical solution and time derivatives that are continuous throughout the entire trajectory. The error of the continuous numerical solution is also known for the entire trajectory. Optimal control for maximizing thrust is also provided within the framework of the new method. Verification of the new approach is presented through a mathematical description and through numerical simulations. The mathematical description provides details of the sailcraft equations of motion, the numerical method used to solve the equations, and the formulation for implementing the equations of motion into the numerical solver. Previous work in the field is summarized to show that the new approach can act as a replacement to previous trajectory propagation methods. A code was developed to perform the simulations and it is also described in this document. Results of the simulations are compared to the flight data from the IKAROS mission. Comparison of the two sets of data show that the new approach is capable of accurately simulating sailcraft motion. Sailcraft and spacecraft simulations are compared to flight data and to other numerical solution techniques. The new formulation shows an increase in accuracy over a widely used trajectory propagation technique. Simulations for two-dimensional, three-dimensional, and variable attitude trajectories are presented to show the multiple capabilities of the new technique. An element of optimal control is also part of the new technique. An additional equation is added to the sailcraft equations of motion that maximizes thrust in a specific direction. A technical description and results of an example optimization problem are presented. The spacecraft attitude dynamics equations take the simulation a step further by providing control torques using the angular rate and acceleration outputs of the numerical formulation.
Subjects/Keywords Aerospace engineering; Finite Element Method; Propagation; Sailcraft; Solar Sail; Spacecraft; Trajectory
Contributors Taghavi, Ray (advisor); Farokhi, Saeed (cmtemember); Keshmiri, Shawn (cmtemember); Zheng, Zhongquan Charlie (cmtemember); Yimer, Bedru (cmtemember)
Language en
Rights Copyright held by the author.
openAccess
Country of Publication us
Record ID handle:1808/19374
Repository ku
Date Retrieved
Date Indexed 2020-08-13
Issued Date 2015-05-31 00:00:00

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