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Front Matter (R1-R12)

Executive Summary (1-10)

1 Introduction (11-21)

2 Policies and Practices in Planetary Protection (22-35)

3 Future Mars Exploration: The Rolling Wave (36-40)

4 Environments on Mars Relative to Life (41-68)

5 Expanding Our Knowledge of the Limits of Life on Earth (69-90)

6 Advances in Technologies for Life Detection and Bioburden Reduction (91-104)

7 Assessing Non-Living Contaminants of Concern (105-110)

8 A Path Forward for Planetary Protection in the 21st Century (111-123)

9 Transition Process and Time Line (124-128)

Appendix A Biographical Sketches of Committee Members and Staff (129-134)

Appendix B Recommendations from Two Previous NRC Reports on Forward Contamination (135-137)

Appendix C Summary of Procedures Currently Used to Assess Bioburden in Spacecraft Assembly Clean Rooms and on Spacecraft (138-139)

Appendix D History of Recommended Values for Probability of Growth (140-140)

Appendix E Approaches to Bioburden Reduction for Lander Missions to Mars (141-143)

Appendix F Ambiguities in Geomorphic Interpretation: Martian Gullies (144-147)

Appendix G Spacecraft Propellant and By-Products as Potential Contaminants (148-151)

Appendix H Acronyms and Abbreviations (152-154)