Planning Considerations Related to the Organic Contamination of Martian Samples and Implications for the Mars 2020 Rover

Table of Contents 1. Executive Summary 2. Introduction 2.1. Introduction to the Mars 2020 OCP 2.1.1. Mars and the potential for habitability 2.1.2. Charge to the OCP 2.1.3. Introduction to the proposed Mars 2020 Mission 2.1.4. Definition of “organic contamination” 2.1.5. A note about units 2.2. Previous work on organic contamination control of acquired samples 2.3. Key concepts 2.3.1. Terrestrial microbial life forms (alive or dead) as sources of organic molecular contaminants 2.3.2. Analytical method limits of detection and contamination limits 2.3.3. Not all contaminants are equal 2.3.4. Contamination control versus contamination knowledge 2.4. Science and PP objectives both drive need for organic analyses 3. Sample-Based Investigations and Measurements 3.1. Need for early survey measurements 3.2. Potential analytical methods for returned samples 3.3. Survey versus targeted analytical methods 3.4. Survey analytical methods 4. Sample-Based Contaminants of Concern 4.1. General considerations 4.1.1. Selection criteria for choosing contaminants of concern 4.1.2. S/N threshold for acceptable contamination 4.1.3. Limits for TOC, individual molecules, or particles 4.1.4. Alive versus dead microbial contamination 4.1.5. The possibility of reproduction of Earth-sourced microbial contaminants in sealed sample tubes 4.2. Considerations related to specific contaminants 4.2.1. Which contaminants? 4.2.1.1. Tier-I contaminants 4.2.2. Allowable levels of contamination