Three recent developments have greatly increased interest in the search for life on Mars. The first is new information about the Martian environment including evidence of a watery past and the possibility of atmospheric methane. The second is the possibility of microbial viability on Mars. Finally, the Vision for Space Exploration initiative included an explicit directive to search for the evidence of life on Mars. These scientific and political developments led NASA to request the NRC's assistance in formulating an up-to-date integrated astrobiology strategy for Mars exploration. Among other topics, this report presents a review of current knowledge about possible life on Mars; an astrobiological assessment of current Mars missions; a review of Mars-mission planetary protection; and findings and recommendations. The report notes that the greatest increase in understanding of Mars will come from the collection and return to Earth of a well-chosen suite of Martian surface materials.Table of Contents


Front Matter
Executive Summary
1 Introduction
2 The Present State of Knowledge About Mars and Possible Life
3 Biosignatures and Abiotic Chemistry
4 Characteristics of Sites for Astrobiological Investigation
5 Methodologies for Advancing Astrobiology
6 Astrobiological Assessment of Current Mars Mission Archictecture
7 Planetary Protection for Mars Missions
8 Findings and Recommendations
Appendix A Martian Features Mentioned in Text
Appendix B Glossary
Appendix C Objectives for Developing a Further Understanding of Biosignatures