The goal of this book is to serve both as a practical technical
reference and a resource for gaining a fuller understanding of the state
of the art of spacecraft momentum control systems, specifically looking
at control moment gyroscopes (CMGs). As a result, the subject matter
includes theory, technology, and systems engineering. The authors
combine material on system-level architecture of spacecraft that feature
momentum-control systems with material about the momentum-control
hardware and software. This also encompasses material on the theoretical
and algorithmic approaches to the control of space vehicles with CMGs.
In essence, CMGs are the attitude-control actuators that make
contemporary highly agile spacecraft possible. The rise of commercial
Earth imaging, the advances in privately built spacecraft (including
small satellites), and the growing popularity of the subject matter in
academic circles over the past decade argues that now is the time for an
in-depth treatment of the topic. CMGs are augmented by reaction wheels
and related algorithms for steering all such actuators, which together
comprise the field of spacecraft momentum control systems. The material
is presented at a level suitable for practicing engineers and those with
an undergraduate degree in mechanical, electrical, and/or aerospace
engineering.