NASA must protect Earth's biosphere even if Mars samples hold mirror life – motivating planetary protection with new scenarios like mirror life - survey of recent research relevant to a Mars sample return - and how to keep Earth's biosphere 100% safe with a miniature telerobotic lab above GEO, and protect other biospheres 100% with sterile robotic explorers

Abstract

In the late 2020s to 2030s, China, and NASA / ESA and Japan plan to return samples from Mars. We need to keep Earth’s biosphere safe from any Martian microbes. Japan’s agency JAXA has the simplest mission, to return samples from the top few centimeters of Mars’s innermost moon Phobos. JAXA can safely return unsterilized samples without any precautions, because any microbes already withstood ejection from Mars, most recently, 700,000 years ago. Then on Phobos they were sterilized similarly to martian meteorites arriving at Earth today from that ancient impact.JAXA warned this meteorite argument is not valid for samples from the Martian surface. NASA’s draft EIS incorrectly says any life from Jezero crater can get here faster and better protected in a meteorite than in a sample tube. Surface dirt and dust can’t get here at all.NASA’s EIS also proposes to return its samples to a Biosafety Level 4 facility. However, the European Space Foundation study in 2012 set size limits well beyond capabilities of a BSL-4 and indeed beyond any current air filter capabilities.We can avoid all these issues and keep Earth 100% safe by sterilizing samples before they get here, with the equivalent of a few hundred million years of Mars surface ionizing radiation. This has virtually no effect on geology, while terrestrial contamination in Perseverance’s samples makes most astrobiology impossible.We can greatly increase science value with contamination free samples in a sterile container returned to a martian gravity centrifuge in an unmanned satellite above GEO, to start Sagan’s “vigorous program of unmanned exobiology”. This is a review of central results in planetary protection literature, with new worst case scenarios such as mirror life, to encourage space agencies to ensure Earth’s biosphere is adequately protected when they return samples from Mars.