Preventing the Forward Contamination of Mars

	Spacecraft Access and Special Regions,	63
	Summary,	63
	References,	64
5	EXPANDING OUR KNOWLEDGE OF THE LIMITS OF LIFE ON EARTH	69
	Modern Views of Microbial Diversity,	69
	Modern Technology and Microbial Ecology,	70
	Organisms at the Limits of Life,	72
	Life in Extreme Environments,	73
	Probability of Growth on Mars,	84
	Summary,	85
	References,	86
6	ADVANCES IN TECHNOLOGIES FOR LIFE DETECTION AND BIOBURDEN REDUCTION	91
	Examples of Methods for Assessing Total Viable Cell Count,	91
	Examples of Methods for Estimating Biodiversity,	94
	Methods for Reducing Bioburden,	99
	Summary,	102
	References,	103
7	ASSESSING NONLIVING CONTAMINANTS OF CONCERN	105
	Types of Contaminants,	106
	Determination of Acceptable Levels of Contamination,	108
	Summary,	109
	References,	109
8	A PATH FORWARD FOR PLANETARY PROTECTION IN THE 21st CENTURY	111
	Expanding the Purpose of Planetary Protection: Safeguarding of Indigenous Life as Well as Protection of Mission Science?,	112
	Programmatic Support,	112
	Needed Research and Reconnaissance,	115
	Transition to a New Approach,	117
	Interim Requirements,	118
	References,	123
9	TRANSITION PROCESS AND TIME LINE	124
	Approach,	124
	Implementation Time Line,	126
	APPENDIXES
	A Biographical Sketches of Committee Members and Staff	131
	B Recommendations from Two Previous NRC Reports on Forward Contamination	135
	C Summary of Procedures Currently Used to Assess Bioburden in Spacecraft Assembly Clean Rooms and on Spacecraft	138
	D History of Recommended Values for Probability of Growth	140
	E Approaches to Bioburden Reduction for Lander Missions to Mars	141
	F Ambiguities in Geomorphic Interpretation: Martian Gullies	144
	G Spacecraft Propellant and By-Products as Potential Contaminants	148
	H Acronyms and Abbreviations	152

Table of Contents

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