Karwas, Alex A.
An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion.
Degree: PhD, Aerospace Engineering, 2015, University of Kansas
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.
Advisors/Committee Members: Taghavi, Ray (advisor), Farokhi, Saeed (cmtemember), Keshmiri, Shawn (cmtemember), Zheng, Zhongquan Charlie (cmtemember), Yimer, Bedru (cmtemember).
Subjects/Keywords: Aerospace engineering; Finite Element Method; Propagation; Sailcraft; Solar Sail; Spacecraft; Trajectory
Figure 5.1 Definition of Sailcraft Azimuth Angle… …105
Figure 6.2 Azimuth Angle of Sailcraft for Thrust Maximization… …106
Figure 6.3 Azimuth Angular Rate of Sailcraft for Thrust Maximization… …107
Figure 6.4 Azimuth Angular Acceleration of Sailcraft for Thrust Maximization… …RHS
Right Hand Side
Solar Radiation Pressure
Sailcraft Trajectory Analysis…
to Zotero / EndNote / Reference
APA (6th Edition):
Karwas, A. A. (2015). An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion. (Doctoral Dissertation). University of Kansas. Retrieved from http://hdl.handle.net/1808/19374
Chicago Manual of Style (16th Edition):
Karwas, Alex A. “An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion.” 2015. Doctoral Dissertation, University of Kansas. Accessed January 25, 2021.
MLA Handbook (7th Edition):
Karwas, Alex A. “An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion.” 2015. Web. 25 Jan 2021.
Karwas AA. An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion. [Internet] [Doctoral dissertation]. University of Kansas; 2015. [cited 2021 Jan 25].
Available from: http://hdl.handle.net/1808/19374.
Council of Science Editors:
Karwas AA. An Unconditionally Stable Method for Numerically Solving Solar Sail Spacecraft Equations of Motion. [Doctoral Dissertation]. University of Kansas; 2015. Available from: http://hdl.handle.net/1808/19374