NASA and ESA will need to sterilize Mars samples to protect Earth's biosphere, because of the many years to complete the legal process and then build a receiving facility to the legally approved design - recommendation to study unsterilized samples telerobotically in a safe orbit above GEO, and return sterilized sub-samples to Earth immediately - PLEASE READ LATEST VERSION AT: https://osf.io/rk2gd
Authors: Walker Robert 
Published: July 2020

PLEASE READ LATEST VERSION AT: https://osf.io/rk2gdThanks! You can dowload previous versions here from the dropdown - but I had to start a new project due to an upload glitch.========NASA plans to return samples from Mars by 2031. They believe there is no surface life in Jezero crater, but can’t rule out life in microhabitats such as are commonly found in Mars analogue deserts on Earth. Life might survive in a swansong biosphere, a relic from a more habitable early Mars. NASA agrees it needs to protect Earth from the possibility of native Martian life in these samples.Most of our laws to protect Earth’s biosphere didn’t exist in 1969. The Apollo sample return procedures had no legal process, and were first made public on the day of launch. During internal review, the experts Vishniac and Sencer told NASA its procedures would not protect Earth, but NASA overruled them on the grounds that their recommendations would postpone the launch date. Today, NASA’s proposal will get full public legal process.The European Space Foundation sample return study from 2012 requires 100% containment of starvation stressed nanobacteria. These pass through 0.1 micron nanopores, far beyond testing limits for HEPA and ULPA filters. We find such technology doesn't exist yet, even as experimental filters in laboratories.The sample return facility is estimated to cost ~$500 million of public funds. NASA need to know their proposed design is legally permitted to start the build. The requirements could change through to the end of the 8+ years legal process. Adding 11+ years for the build, we find an earliest date of 2039 to return unsterilized samples, with further delays likely.However samples can be sterilized at a level sufficient for planetary protection while preserving geological interest, evidence for past life, and ability to detect present day life. This becomes an unrestricted sample return; a relatively simple process under the Outer Space Treaty.Perseverance's primary objective is past life, rather than present day life. We propose the ESA fetch rover adds a dust sample, a capability dropped from Perseverance, to search for dust-storm resistant Martian propagules. These could be transported from distant parts of Mars.We also suggest the ESA fetch rover is modified to dig an extra sample of dirt including the brine layers Curiosity discovered centimetres below the surface of sand dunes. Did Viking detect complex chemistry or native life in the 1970s?If there is a significant chance of viable present day life in these samples, we suggest returning to a satellite in a stable inclined orbit above GEO in Earth's Laplace plane or "ring plane". This orbit has many advantages for protection of Earth, the Moon, and other satellites. Sterilized subsamples can be returned to Earth immediately for geological studies, and preliminary astrobiological work.Should signs of life be found, either in the sterilized samples or in orbit, scientists can send instruments already designed to search for life in situ on Mars, teleoperated in the orbital facility with close to zero latency. Decisions about what to do next depend on what they discover.This article examines specific worst case scenarios for Martian life, such as a blue-green algae with everything flipped as in a mirror: DNA spirals anticlockwise, and amino acids, carbohydrates, sugars, are all in their mirror forms. Synthetic biologists have started a step-by-step process to flip a terrestrial cell to mirror life. They warn of a risk that mirror life could gradually transform parts of terrestrial ecosystems to indigestible mirror organics, giving it a competitive advantage. Synthetic mirror life needs containment to a higher level of safety than conventional biosafety laboratories. To keep Earth safe, mirror cells will depend on chemicals only available in the laboratory. To achieve a similar level of safety for Martian mirror life, we might have to leave it in orbit.In some scenarios we look at, Martian life is harmless or even beneficial. However in worst case scenarios Mars's biosphere can never mix safely with ours. Quarantine of astronauts returning from Mars can also be insufficient to protect our biosphere in some scenarios.Any discoveries from early missions like Perseverance can only be a first step to inform future searches. Our future possibilities, and opportunities, depend on whether there is life on Mars and what it's like. Answering this seems a top priority for space colonization enthusiasts, and astrobiologists alike.With a combined effort, future astronauts in orbit around Mars can conduct rapid surveys of proposed potential habitats, controlling surface robots with low latency telepresence. This would help resolve these questions as fast as possible.This article concludes that the complex laws already in place to protect Earth’s biosphere are both understandable and necessary.