# Spacecraft Attitude Dynamics

## AAE59000

3

### Learning Objective:

The development of spacecraft rigid body equations of motion in terms of quaternions, with external torques. Determination of the attitude stability of the resulting rotational motion of the spacecraft. Stabilization techniques presented and the impact determined through numerical simulations.

### Description:

This senior level course in vehicle dynamics is based on the fundamentals from previous courses in particle and rigid body dynamics. Here, the focus is the vehicle orientation,specifically spacecraft. The students acquire the necessary and most fundamental technical competence in natural spacecraft attitude motion and the introduction to attitude control. An ability to formulate these engineering problems and the skills to analyze (as well as solve) them is addressed through homework exercises; this includes extensive computational work and the interpretation of results. The ability to communicate their analysis techniques and orally interpret their results is practiced in the homework as well as structured class discussions. The methodology is emphasized as an engineering skill with applications to other vehicle issues. Depending on the NASA launch schedules during the current semester, the projects/homework are correlated to actual spacecraft/missions. Previous missions are used as examples as well.
Spring 2019 Syllabus

### Topics Covered:

1. Introduction to modern spacecraft dynamics (background and motivation) 2. Fundamental concepts including the mathematical formalism of dyadics and the mechanics of energy and angular momentum; rotational kinematics including direction cosines, Euler angles, and Euler parameters (quaternions) as kinematic variables; coordinate systems and transformations, angular velocity and kinematic differential equations 3. External torques on a spacecraft; gravitational interactions between particles and bodies;center of gravity and centrobaric bodies 4. Simple spacecraft (axisymmetric and unsymmetric) and dynamic differential equations. Torque-free rotational motion; stability analysis; impact of external torques; spin stabilization; gravity gradient stabilization; dual-spinners; mass movement and momentum exchange techniques (momentum wheels, reaction wheels, control moment gyros); three-axis stabilization

### Prerequisites:

AAE 340, AAE 364 (or equivalent)

### Applied / Theory:

https://mycourses.purdue.edu

### Web Content:

Grades, lecture notes, homework assignments, solutions

### Homework:

Initially, approximately one assignment per week; projects assigned later in the semester. Use of calculator and computer required during semester. Absolutely NO late homework will be accepted for any reason.

### Projects:

A Final project will be submitted in lieu of a Final exam.

### Exams:

Three midterm exams.

### Textbooks:

Official textbook information is now listed in the Schedule of Classes. NOTE: Textbook information is subject to be changed at any time at the discretion of the faculty member. If you have questions or concerns please contact the academic department.
Tentative:None required.

### Computer Requirements:

ProEd Minimum computer requirements. Software packages developed specifically for astrodynamics applications may be introduced. However, you will also be required to develop your own programs and/or MATLAB scripts.

TBA

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