Planetary protection for human exploration of Mars

Human astronauts have unique capabilities that could greatly facilitate scientific exploration of other planets. However, when searching for life beyond Earth, these capabilities can be utilized effectively only if the biological contamination associated with human presence is monitored and minimized. This is termed planetary protection, and is a critical element in human exploration beyond Earth. Planetary protection must be incorporated from the earliest stages of mission planning and development, to ensure proper implementation. Issues involve both “forward contamination”, the contamination of other solar system bodies by Earth microbes and organic materials, and “backward contamination”, the contamination of Earth systems, including astronauts, by biological hazards or potential alien life. Conclusions from a number of international workshops held over the last six years recognize that some degree of forward contamination associated with human astronaut explorers is inevitable. Nevertheless, when humans are exploring space the principles and policies of planetary protection, developed by COSPAR in accordance with the 1967 Outer Space Treaty, still apply. Implementation guidelines include documenting and minimizing contamination of the exploration targets, control at the most stringent levels for locations in which Earth life might grow, and protection of humans from exposure to untested planetary materials. Preventing harmful contamination of the Earth must be of the highest priority for all missions.