Protecting the Environment of Celestial Bodies: The Need for Policy and Guidelines, published in 2011, 81 pages. This IAA Study on Protecting the Environment of Celestial Bodies (PECB) aims to provide an overview of existing methods of planetary protection and their feasibility from the perspective of biological, chemical, legal, economic and other viewpoints. By doing so, the Study goes deliberately beyond the interpretation of “Planetary Protection” by COSPAR (Committee on Space Research), which is generally used as a set of methods for protecting the planets from biological contamination to avoid compromising future astrobiological research. In view of limits on the size of this volume, the Study concentrates mainly on the Moon and Mars environments. It is fully recognized, however, that the environments of other celestial bodies, including asteroids that may be visited by manned spacecraft before a mission to Mars, are also worthy of consideration.