This second edition of Applied Orbit Perturbation and Maintenance by Chia-Chun (George) Chao with new inputs from Felix Hoots is a welcome update to an already established astrodynamics text by the primary author.

Building from the fundamental theory of orbit motion through the development of classical elements and complex perturbed trajectories to application to mission analysis problems, the text provides a comprehensive treatise and consideration of appropriate approaches to orbit representation and modelling solutions. The chapters on orbit maintenance of different classical orbits ranging from low-Earth up to higher altitude orbits are particularly useful, most notably station-keeping and collocation of geostationary satellites and will prove beneficial to the modeller and operator/analyst alike in providing background rationale for particular operational strategies.

The chapter on the strategies and long-term stability of end of life disposal orbits is very helpful in explaining the need for, and practical implementation of, measures to limit the proliferation of space debris by removing satellites from crowded orbits once a mission is complete. This topic is further elaborated with a dedicated chapter on space debris, explaining the background history and predicted future evolution of the space object population, outlining some models that are available to the practitioner and relevant disposal strategies, in addition to underlining the need for space surveillance and tracking.

Finally, the appendices are a very useful source of orbital theory ranging from third body gravitational perturbation through solar radiation pressure impact and simplified solutions to both conservative and non-conservative force influence on trajectories.

This book is recommended to both undergraduates and postgraduate students and is a very valuable reference for mission designers and those involved in the day-to-day operations of satellites and is an excellent primer for any aspiring astrodynamicists.