In-Situ Radioisotope Sterilization for Backward and Forward Contamination - Enabling low-mass, Low-Complexity Solutions for Planetary Protection

The quest to protect planetary bodies from contamination by Earth life and to shield Earth from potential extraterrestrial life forms is a critical concern for NASA's planetary science missions. The Mars Sample Return and other decadal missions targeting the icy moons of the outer solar system are flagship missions prioritized by NASA. However, they face significant cost and complexity issues from stringent planetary protection needs. Current planetary protection measures involve complex sterilization processes, redundant seal containments, lengthy quarantines, power, and special handling procedures, all adding significant mass and cost to the missions. Our proposal introduces a paradigm-shifting radioisotope-based sterilization system. Unlike traditional methods that use heat or chemicals, which can damage samples and leave residues, this innovative technology utilizes primary ionizing radiation to sterilize nucleic acids (DNA and RNA) and prions without affecting the bulk material. This method is particularly advantageous for long-duration missions, as it allows for sterilization over the extended return trip from Earth (forward contamination) and returning from Earth (backward contamination). The long duration allows for a low-activity, low hazard radiation source. This approach provides a low-mass, low-complexity, low-cost solution for robust planetary protection. In addition, our sterilization techniques can target multiple types of radioisotopes, which can be used either to sterilize a surface or a volume based on the type and energy of radiation. This technology would add a new tool to the planetary protection toolbox and help NASA and emerging commercial companies comply with planetary protection rules at a low cost and minimal impact on conops.