Front Matter -- Preface -- Acknowledgment of Reviewers -- Contents -- Summary -- 1 Introduction -- 2 Current Knowledge of the Radiation Environment -- 3 Radiation Effects -- 4 Shielding Approaches and Capabilities -- 5 Strategy for Radiation Risk Mitigation -- 6 Findings and Recommendations -- Appendixes -- A Statement of Task -- B Biographies of Committee Members -- C Committee Meeting Agendas and Speakers -- D Glossary and Acronyms.