Developing Biological ISRU: Implications for Life Support and Space Exploration

I.I. Brown, C.C. Allen, D.H. Garrison, S.A. Sarkisova, C. Galindo Jr., D.S. McKayNASA JSC, Mail code KA, 2101 NASA Road One, Houston, TX, 77058Introduction: Our ultimate goal in space is to be able to go anywhere, at any time with whatevercapabilities to accomplish any task or job we choose to undertake. We are light-years away from achievingsuch a goal, largely because we must drag everything we need in space with us from the bottom of a verydeep gravity well – the Earth’s surface. As long as this paradigm prevails, we will remain mass- and power-limited in space and thus, capability-limited as well.In-situ production of consumables (In-Situ Resource Utilization-ISRU) will significantly facilitatecurrent plans for human exploration and colonization of the solar system, especially by reducing thelogistical overhead such as recurring launch mass. The production of oxygen from local materials isgenerally recognized as the highest priority process for lunar and Martian ISRU, for both human metabolicand fuel oxidation needs. The most challenging technology developments for future lunar settlements maylie in the extraction of elements (O, Fe, Mn, Ti, Si, etc) from local rocks and soils for life support systems[LSS], including extraterrestrial greenhouses, and the production of propellants.However, while the majority of physico-chemical methods proposed for O2 extraction fromlunar/Martian regolith [1] are intended to supply LSS only with oxygen, they are not able to contribute toother important processes such as CO2 sequestration and/or food production..On the other hand Biological Life Support System as the European Micro-Ecological Life SupportSystem Alternative (MELiSSA) [2]. is a net consumer of ISRU products without a net return to in-situtechnologies, e.g. to extract elements, as a result of complete closure of MELiSSA. That is why theinvestigation of more efficient air bioregeneration techniques based on the metabolism of lower orderphotosynthetic organisms with ability to dissolve (weather) in situ rocks appears to be very timely andrelevant. Cyanobacteria (CB) are known as effective producers of O2, proteins, vitamins, andimmunomodulators [3] and some of those possess litholitic capabilities [4]Method: We have been using several species of siderophilic CB isolated from iron-depositing hotsprings in Yellowstone National Park [5] and grown in a special photoreactor to dissolve (weather)stimulants of lunar regolith. Such parameters as elements released from stimulants, their accumulation incells, biomass production and oxygen evolution are continuously monitored.Main findings: 1) supplementing very dilute media for cultivation of CB with analogs of lunar orMartian regolith effectively supported the proliferation of CB; 2) O2 evolution by siderophiliccyanobacteria cultivated in diluted media but supplemented with iron-rich rocks was higher than O2evolution by same strain in undiluted medium; 3) preliminary data suggest that organic acids produced byCB are involved in iron-rich mineral dissolution; 4) the CB studied can accumulate iron on and in theircells; 4) sequencing of the cyanobacterium JSC-1 genome revealed that this strain possesses molecularfeatures which make it applicable for the cultivation in special photoreactors on Moon and Mars.Conclusion: As a result of pilot studies, we propose, to develop a concept for semi-closed integratedsystem that uses CB to extract useful elements to revitalize air and produce valuable biomolecules. Such asystem could be the foundation of a self-sustaining extraterrestrial outpost (Hendrickx, De Wever et al.,2005; Handford, 2006). A potential advantage of a cyanobacterial photoreactor placed between LSS andISRU loops is the possibility of supplying these systems with extracted elements and compounds from theregolith. In addition, waste regolith may be transformed into additional products such as methane, biomass,and organic and inorganic soil enrichment for the cultivation of higher plants.References: [1] Schrunk BG, , Sharpe D., Cooper BL, Thangavelu M. (2007) The Moon: resources,future development, and settlement. 2nd ed. Springer, 561 p. [2] [3] Hendrickx, L., H. De Wever, et al.(2006). Research in Microbiology 157(1): 77-86. [3] Brown I.I. et al. (2008) 37th COSPAR ScientificAssambly, # F41-0010-08. [4] Brown I.I. et al. (2007) in: Algae and Cyanobacteria in ExtremeEnvironments. Springer:Israel. 425-442.[4]