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Synthetic biology can greatly accelerate the development of human space exploration, to the point of allowing permanent human bases on Mars within our lifetime. Among the technological issues to be tackled is the need to provide the consumables required to sustain crews, and using biological systems for the on-site production of resources is an attractive approach. However, all organisms we currently know have evolved on Earth and most extraterrestrial environments stress the capabilities of even terrestrial extremophiles. Two challenges consequently arise: organisms should survive in a metabolically active state with minimal maintenance requirements, and produce compounds of interest while relying only on inputs found in the explored areas. A solution could come from the tools and methods recently developed within the field of synthetic biology. The societal implications are complex: there are implications with synthetic biology and human space colonization independently, and together there are potentially more issues. Establishing colonies relying to a large extent on modified organisms and transferring the developed technologies to terrestrial applications raises a wide range of critical ethical questions and unprecedented societal impacts, on Earth as well as on colonized planetary bodies. The scenario of humans as a multi-planet species should be addressed now, as technologies aimed at making it happen are already under development. Here we give a brief overview of the synthetic biology technologies that are being developed to aid human space exploration, before discussing the impacts of proposed medium-term scenarios on the evolution of our society.

[1]  Alexander A. Tikhomirov,et al.  Biological life support systems for a Mars mission planetary base: Problems and prospects , 2007 .

[2]  Andrew C Schuerger,et al.  Growth of Serratia liquefaciens under 7 mbar, 0°C, and CO2-enriched anoxic atmospheres. , 2013, Astrobiology.

[3]  R. Helm,et al.  Engineering Desiccation Tolerance inEscherichia coli , 2000, Applied and Environmental Microbiology.

[4]  A. Casadevall,et al.  A new synthesis for antibody-mediated immunity , 2011, Nature Immunology.

[5]  R. Lenski,et al.  Microbial genetics: Evolution experiments with microorganisms: the dynamics and genetic bases of adaptation , 2003, Nature Reviews Genetics.

[6]  T. Lyons,et al.  Directed evolution of a filamentous fungus for thermotolerance , 2009, BMC biotechnology.

[7]  M. Ohmori,et al.  Growth of terrestrial cyanobacterium, Nostoc sp., on Martian Regolith Simulant and its vacuum tolerance , 2008 .

[8]  W. Nicholson,et al.  Growth of Carnobacterium spp. from permafrost under low pressure, temperature, and anoxic atmosphere has implications for Earth microbes on Mars , 2012, Proceedings of the National Academy of Sciences.

[9]  G. Muyzer,et al.  Application of bacteria as self-healing agent for the development of sustainable concrete , 2010 .

[10]  C. Cockell,et al.  Experimental methods for studying microbial survival in extraterrestrial environments. , 2010, Journal of microbiological methods.

[11]  R. Dahlgren,et al.  Volcanic ash soils : genesis, properties and utilization , 1993 .

[12]  Carlton C. Allen,et al.  Bio-Weathering of Lunar and Martian Rocks by Cyanobacteria: A Resource for Moon and Mars Exploration , 2008 .

[13]  A. Kereszturi,et al.  Results on the survival of cryptobiotic cyanobacteria samples after exposure to Mars-like environmental conditions , 2013, International Journal of Astrobiology.

[14]  G. Horneck The microbial case for Mars and its implication for human expeditions to Mars , 2008 .

[15]  Tilman Spohn,et al.  Adaptation of an Antarctic lichen to Martian niche conditions can occur within 34 days , 2014 .

[16]  Michele Perchonok,et al.  Guidelines and Capabilities for Designing Human Missions , 2003 .

[17]  Robert Verpoorte,et al.  Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering , 2011, Applied Microbiology and Biotechnology.

[18]  Barbara Negri,et al.  Plant bioregenerative life supports: The Italian CAB Project , 2007 .

[19]  W. Nicholson,et al.  Exploring the Low-Pressure Growth Limit: Evolution of Bacillus subtilis in the Laboratory to Enhanced Growth at 5 Kilopascals , 2010, Applied and Environmental Microbiology.

[20]  Robert M. Zubrin The Economic Viability of Mars Colonization , 2018 .

[21]  D. Ewing The directed evolution of radiation resistance in E. coli. , 1995, Biochemical and biophysical research communications.

[22]  Max Mergeay,et al.  From the deep sea to the stars: human life support through minimal communities. , 2007, Current opinion in microbiology.

[23]  S. Shanmugasundaram,et al.  Uninduced ammonia release by the nitrogen‐fixing cyanobacterium Anabaena , 1986 .

[24]  Andrew C. Schuerger,et al.  Low pressure and desiccation effects on methanogens: Implications for life on Mars , 2011 .

[25]  Stephen J. Hoffman,et al.  Human Exploration of Mars: The Reference Mission of the NASA Mars Exploration Study Team , 1997 .

[26]  Remy Chait,et al.  Building a morbidostat: an automated continuous-culture device for studying bacterial drug resistance under dynamically sustained drug inhibition. , 2013, Nature protocols.

[27]  Laurent Poughon,et al.  HUMEX, a study on the survivability and adaptation of humans to long-duration exploratory missions, part II: Missions to Mars , 2006 .

[28]  R Gerzer,et al.  HUMEX, a study on the survivability and adaptation of humans to long-duration exploratory missions, part I: lunar missions. , 2003, Advances in space research : the official journal of the Committee on Space Research.

[29]  Bérangère Farges,et al.  Simulation of the MELiSSA closed loop system as a tool to define its integration strategy , 2009 .

[30]  Robert M. Zubrin,et al.  The case for Mars : the plan to settle the red planet and why we must , 1996 .

[31]  Madhu Thangavelu,et al.  Bio-regenerative life support system development for Lunar/Mars habitats , 2012 .

[32]  K. Lehto,et al.  Characterization of growth and photosynthesis of Synechocystis sp. PCC 6803 cultures under reduced atmospheric pressures and enhanced CO2 levels , 2005, International Journal of Astrobiology.

[33]  L. Rothschild,et al.  Elucidating Microbial Adaptation Dynamics via Autonomous Exposure and Sampling , 2013 .

[34]  L. Rothschild,et al.  Earth analogs for Martian life. Microbes in evaporites, a new model system for life on Mars. , 1990, Icarus.

[35]  W. Nicholson,et al.  Evolution of Bacillus subtilis to enhanced growth at low pressure: up-regulated transcription of des-desKR, encoding the fatty acid desaturase system. , 2012, Astrobiology.

[36]  James Newcomb,et al.  Scenarios for the future of synthetic biology , 2008 .

[37]  G. Perani Military technologiesand commercial applications: Public policies in NATO countries , 1997 .

[38]  Terence Hwa,et al.  Need-based activation of ammonium uptake in Escherichia coli , 2012, Molecular systems biology.

[39]  J. Boling,et al.  EXTREMOPHILES FOR ECOPOIESIS: DESIRABLE TRAITS FOR AND SURVIVABILITY OF PIONEER MARTIAN ORGANISMS , 2007 .

[40]  R. Dahlgren,et al.  Chapter 5 Mineralogical Characteristics of Volcanic Ash Soils , 1993 .

[41]  A. Arkin,et al.  Towards synthetic biological approaches to resource utilization on space missions , 2015, Journal of The Royal Society Interface.

[42]  R. Goldman,et al.  EXPERIMENTAL EVOLUTION OF ULTRAVIOLET RADIATION RESISTANCE IN ESCHERICHIA COLI , 2011, Evolution; international journal of organic evolution.

[43]  Mark Nelson,et al.  Closed Ecological Systems, Space Life Support and Biospherics , 2010 .

[44]  Annick Wilmotte,et al.  Microbial ecology of the closed artificial ecosystem MELiSSA (Micro-Ecological Life Support System Alternative): reinventing and compartmentalizing the Earth's food and oxygen regeneration system for long-haul space exploration missions. , 2006, Research in microbiology.

[45]  Charles S. Cockell,et al.  Use of cyanobacteria for in-situ resource use in space applications , 2010 .

[46]  G. Horneck,et al.  Opportunities and constraints of closed man-made ecological systems on the moon , 1994 .

[47]  J. Collins,et al.  Synthetic Biology Moving into the Clinic , 2011, Science.

[48]  U. Linne,et al.  Microalgae as bioreactors for bioplastic production , 2011, Microbial cell factories.

[49]  P. Silver,et al.  Sun-driven microbial synthesis of chemicals in space , 2011, International Journal of Astrobiology.

[50]  Royston Goodacre,et al.  Metabolomics-assisted Synthetic Biology This Review Comes from a Themed Issue on Analytical Biotechnology Edited Metabolite and Metabolic Engineering , 2022 .

[51]  V. Gavrilovic,et al.  Genome shuffling of Lactobacillus for improved acid tolerance , 2002, Nature Biotechnology.

[52]  P. Hallenbeck Microbial Technologies in Advanced Biofuels Production , 2012, Springer US.

[53]  Andrea Klug,et al.  Man Made Closed Ecological Systems , 2016 .

[54]  George H. McArthur,et al.  The role of synthetic biology for in situ resource utilization (ISRU). , 2012, Astrobiology.

[55]  C. Cockell Synthetic geomicrobiology: engineering microbe–mineral interactions for space exploration and settlement , 2011, International Journal of Astrobiology.

[56]  Wendy Schackwitz,et al.  Directed Evolution of Ionizing Radiation Resistance in Escherichia coli , 2009, Journal of bacteriology.

[57]  Nathan E Lewis,et al.  Microbial laboratory evolution in the era of genome-scale science , 2011, Molecular systems biology.

[58]  J. Keasling,et al.  Microbial engineering for the production of advanced biofuels , 2012, Nature.

[59]  Jay D Keasling,et al.  Metabolic engineering of microbial pathways for advanced biofuels production. , 2011, Current opinion in biotechnology.

[60]  Jacques Arnould,et al.  Planetary protection issues related to human missions to Mars , 2008 .

[61]  M. Marinova,et al.  The physics, biology, and environmental ethics of making mars habitable. , 2001, Astrobiology.

[62]  K. Timmis,et al.  Chaperonins govern growth of Escherichia coli at low temperatures , 2003, Nature Biotechnology.

[63]  M. Hirai,et al.  Pathway-Level Acceleration of Glycogen Catabolism by a Response Regulator in the Cyanobacterium Synechocystis Species PCC 68031[W] , 2014, Plant Physiology.

[64]  Farren J. Isaacs,et al.  Programming cells by multiplex genome engineering and accelerated evolution , 2009, Nature.

[65]  J. Allen,et al.  Biosphere 2: The Human Experiment , 1991 .

[66]  P. Rettberg,et al.  The BOSS and BIOMEX space experiments on the EXPOSE-R2 mission: endurance of the desert cyanobacterium Chroococcidiopsis under simulated space vacuum, Martian atmosphere, UVC radiation and temperature extremes. , 2013 .

[67]  Charles S Cockell,et al.  Geomicrobiology beyond Earth: microbe-mineral interactions in space exploration and settlement. , 2010, Trends in microbiology.

[68]  Kathryn Denning,et al.  Astrobiology and society: building an interdisciplinary research community. , 2012, Astrobiology.

[69]  P. Silver,et al.  Engineering Cyanobacteria To Synthesize and Export Hydrophilic Products , 2010, Applied and Environmental Microbiology.

[70]  Robert E. Jinkerson,et al.  Genetic Engineering of Algae for Enhanced Biofuel Production , 2010, Eukaryotic Cell.

[71]  Jo‐Shu Chang,et al.  Direct conversion of Spirulina to ethanol without pretreatment or enzymatic hydrolysis processes , 2013 .

[72]  G. Reitz,et al.  Adaptation of Bacillus subtilis cells to Archean-like UV climate: relevant hints of microbial evolution to remarkably increased radiation resistance. , 2010, Astrobiology.

[73]  J. P. Harrison,et al.  The limits for life under multiple extremes. , 2013, Trends in microbiology.

[74]  A. Incharoensakdi,et al.  Enhancement of hydrogen production by the filamentous non-heterocystous cyanobacterium Arthrospira sp. PCC 8005 , 2012 .

[75]  L. Rothschild,et al.  A powerful toolkit for synthetic biology: Over 3.8 billion years of evolution , 2010, BioEssays : news and reviews in molecular, cellular and developmental biology.

[76]  D. Dykhuizen Chemostats used for studying natural selection and adaptive evolution. , 1993, Methods in enzymology.

[77]  D. L. De Vincenzi Planetary protection issues and the future exploration of Mars , 1992 .

[78]  K. Lehto,et al.  Suitability of different photosynthetic organisms for an extraterrestrial biological life support system. , 2006, Research in microbiology.

[79]  N. Frigaard,et al.  Cyanobacterial biomass as carbohydrate and nutrient feedstock for bioethanol production by yeast fermentation , 2014, Biotechnology for Biofuels.

[80]  S. Baum Is Humanity Doomed? Insights from Astrobiology , 2010 .

[81]  E. Tajika,et al.  Atmospheric collapse and transport of carbon dioxide into the subsurface on early Mars , 2006 .

[82]  Roger D. Launius,et al.  Societal Impact of Spaceflight , 2012 .

[83]  Martin Fussenegger,et al.  Emerging biomedical applications of synthetic biology , 2011, Nature Reviews Genetics.

[84]  Y. Hua,et al.  Expression of Deinococcus radiodurans PprI enhances the radioresistance of Escherichia coli. , 2003, DNA repair.

[85]  F Gòdia,et al.  MELISSA: a loop of interconnected bioreactors to develop life support in space. , 2002, Journal of biotechnology.

[86]  C P McKay,et al.  Planetary protection issues in advance of human exploration of Mars. , 1989, Advances in space research : the official journal of the Committee on Space Research.

[87]  Christopher A. Voigt,et al.  Realizing the potential of synthetic biology , 2014, Nature Reviews Molecular Cell Biology.

[88]  James M Graham,et al.  The biological terraforming of Mars: planetary ecosynthesis as ecological succession on a global scale. , 2004, Astrobiology.

[89]  L. Rothschild,et al.  Sustainable life support on Mars – the potential roles of cyanobacteria , 2015, International Journal of Astrobiology.

[90]  Geoffrey A. Landis,et al.  A Chemical Approach to Carbon Dioxide Utilization on Mars , 1997 .

[91]  Jeffrey C Way,et al.  Engineering cyanobacteria to generate high-value products. , 2011, Trends in biotechnology.

[92]  Federico Maggi,et al.  Space agriculture in micro- and hypo-gravity: A comparative study of soil hydraulics and biogeochemistry in a cropping unit on Earth, Mars, the Moon and the space station , 2010 .

[93]  Andrew Steele,et al.  Mars methane detection and variability at Gale crater , 2015, Science.

[94]  D. Ming,et al.  Volatile and Organic Compositions of Sedimentary Rocks in Yellowknife Bay, Gale Crater, Mars , 2014, Science.

[95]  Philippe Marlière,et al.  Chemical evolution of a bacterium's genome. , 2011, Angewandte Chemie.

[96]  Jason G Matheny,et al.  Reducing the Risk of Human Extinction , 2007, Risk analysis : an official publication of the Society for Risk Analysis.

[97]  M. Radman,et al.  Oxidative Stress Resistance in Deinococcus radiodurans , 2011, Microbiology and Molecular Reviews.

[98]  Ahmad S. Khalil,et al.  Synthetic biology: applications come of age , 2010, Nature Reviews Genetics.

[99]  Charles S Cockell,et al.  Trajectories of martian habitability. , 2014, Astrobiology.

[100]  Timothy S. Ham,et al.  Production of the antimalarial drug precursor artemisinic acid in engineered yeast , 2006, Nature.

[101]  A E Drysdale,et al.  Life support approaches for Mars missions. , 2003, Advances in space research : the official journal of the Committee on Space Research.

[102]  M. Fussenegger,et al.  Synthetic biology advancing clinical applications. , 2012, Current opinion in chemical biology.

[103]  Mario Pagliaro,et al.  The Future of Glycerol , 2008 .

[104]  G. Massa,et al.  PLANT-GROWTH LIGHTING FOR SPACE LIFE SUPPORT: A REVIEW , 2007 .

[105]  A E Drysdale,et al.  The minimal cost of life in space. , 2004, Advances in space research : the official journal of the Committee on Space Research.

[106]  J. Keasling,et al.  Engineering a mevalonate pathway in Escherichia coli for production of terpenoids , 2003, Nature Biotechnology.

[107]  J. Gitelson Biological life-support systems for Mars mission. , 1992, Advances in space research : the official journal of the Committee on Space Research.

[108]  Robert M. Zubrin,et al.  Mars Direct: Combining Near-Term Technologies to Achieve a Two-Launch Manned Mars Mission , 1990 .

[109]  K. Shanmugam,et al.  Isolation and characterization of nitrogenase-derepressed mutant strains of cyanobacterium Anabaena variabilis , 1986, Journal of bacteriology.

[110]  Tetsuya Tokano,et al.  Water on Mars and Life , 2005 .

[111]  W. Verstraete,et al.  Influence of urea and calcium dosage on the effectiveness of bacterially induced carbonate precipitation on limestone , 2010 .