35322 - Spacecraft Attitude Dynamics and Control (2nd cycle)

Learning outcomes

In the two-years Masters Degree in Aerospace Engineering, this course is aimed at providing students with an introduction to the subject of spacecraft attitude dynamics, determination and control. The first part of the course is dedicated to an introduction to the space environment and the description of attitude dynamics. In the second part of the course the various techniques of attitude determination and control are introduced.

Course contents

Introduction to the Space Environment

• Planetary and Earth Magnetic Fields;
• Atmospheres and their effect on satellites;
• Ionospheres;
• the Sun and the Solar Wind;
• Interaction between the Solar Wind and the magnetospheres;
• Space Radiations: sources and typical energies; effects on human body and on on-board electronic systems.
  Mitigation strategies for electronic systems.

 

Elements of attitude dynamics

• Attitude Parameterization with respect to an intertial reference frame: Euler axis and angle, quaternions, Euler angles;
• Spacecraft attitude propagation:
• Dynamic Equations: Euler rigid body equations
• Kinematic Equations in terms of quaternions and Euler angles
• Description of various external torques;
• Disturbance torque: Gravity gradient, Aerodynamic Torque, Solar Radiation Pressure Torque, Residual magnetic dipole Torque;
• Control torque: Momentum/Reaction Wheels torque (modification to Euler's Equations); Magnetic Control Torque; Thrusters Control Torque;
• Analytic solution to the attitide dynamics of the torque-free rigid body motion; particular solution for gyroscopic bodies. Integrals of motion and physical meaning of their equations; qualitative descrition of the attitude motion of a gyroscopic body

Elements of attitude determination

• Deterministic Methods:
• For Spin stabilized spacecraft
• For Three-axis Stabilized spacecraft

• Recursive Methods (estimation filters):
• Linear Estimation of a state vector;
• Introduction to recursive methods
• The Kalman Filter: equations and practical design aspects

Elements of attitude control

• Passive Control:

          - Spin Stabilization;

          - Gravity Gradient Stabilization;

• Active Control:

          - Momentum/Reaction Wheels control;

          - On-Off Control, thruster systems.

Readings/Bibliography

Course notes distributed by the lecturer

Teaching methods

Lectures are mostly held by the course teacher.  In lecturing hours the subjects are presented by the lecturer, including the explicit demonstration of all mathematical formulas introduced and to the presentation of the methods to solve the problems given in the practicing hours. The proposed exercises require the use of pocket calculators for the solution of the mathematical end engineering problems given by the lecturer

Assessment methods

The examination is oral and usually constists of three questions on various subjects. In the course of the exam it will be assessed the ability to the student to resolve new problems or at least to set up the correct resolutive strategy.  The assessment of such ability has a fundamental weight in the attribution of the final marks.  The student must pass in at least two of the three questions placed by the lecturer in order to pass the examination.

Teaching tools

LCD projector, overhead projector and PC are used in addition to the standard blackboard.

Office hours

See the website of Paolo Tortora