Warning: before landing

WARNING! READ THIS CAREFULLY BEFORE LANDING! Under the regulations described here, much of Mars is probably suitable for human expeditions because it is too cold and dry for surface materials to become contaminated by terrestrial microbes, provided spacesuits and equipment minimise leakage. Some human contamination is unavoidable. Surface-operation guidelines prevent greater contamination by setting limits for landing, habitat use, extravehicular activity (EVA) and in-situ resource utilisation (ISRU). Any unexplored Martian site must be assessed by robotic scouts before the crew approaches it. A robotic component travelling with the crew can obtain the necessary information. Biological planetary protection safeguards Solar System bodies from contamination by terrestrial life, allowing scientific investigation of potential habitats, and protects Earth from potentially harmful biological contamination from other bodies. Forward contamination means terrestrial microbes and organic matter contaminating another body; backward contamination means extraterrestrial life contaminating Earth, if such life exists. Protecting Earth from possible Martian biological contamination is the highest planetary-protection priority in Mars exploration. Some contamination by human explorers is unavoidable: every activity in a surface mission cannot be performed within a completely closed system. The crew and their life-support systems will inevitably encounter Martian materials. Restrictions include defining safety zones demonstrated to be safe for people. Astronauts may enter only areas shown to be safe. Robotic exploration must establish the safety of areas around habitats before EVA is permitted. Special Regions may be accessed only with clean, sterilised equipment to avoid contamination. Collected samples may be transferred only under appropriate controls to prevent contamination towards Earth. During and after the mission, quarantine facilities must be available for the whole crew and individuals if contact with a Martian life form is even suspected (Conley and Rummel; COSPAR 2009; NASA 2020, as cited in the original). If a spacecraft risks a hard landing or impact that could biologically contaminate a Special Region, the entire landing system must be sterilised as Category IVc, a Special Region landing. For Category IVa missions—landers not searching for Martian life—the bioburden must be limited to 300,000 bacterial spores on surfaces from which spores could reach the Martian environment. Heat-tolerant parts must be sterilised at 114 °C. Higher-risk missions, including Category IVc, require a much higher level of sterilisation.