Planetary protection considerations for future exploration

Since 1963, an international consensus policy has been in place to control contamination of planets by both terrestrial organisms and organic constituents. The policy, maintained by the Committee on Space Research of the International Council for Science (ICSU, originally the International Council of Scientific Unions) and reflected in a policy of the National Aeronautics and Space Administration, lays out a framework of guidelines for implementing missions while avoiding mission-caused microbial contamination. During the course of structuring today´s active program to explore our solar system, especially in the face of a focus on astrobiology and the search for life, it has become increasingly apparent that planetary protection factors will have a significant impact on future mission design, cost, and complexity. For some missions, the microbial load on the hardware must be limited during manufacturing and building processes, and controlled during assembly, test and launch operations. These limitations can be assured by adopting strict clean room standards, including personnel and operational procedures, re-cleaning with appropriate fluids to maintain cleanliness during pre-launch processing of hardware, and the possible necessity to employ a terminal sterilization process. For these and other missions, it is also necessary to examine the hazards of accidental impacts and other events that may cause the release of organisms in environments where they may grow and thrive. Therefore, various constraints on flight trajectories, orbital altitudes, and dwell times must be considered and implemented during the design phase of such missions.