SALT-LOVING (HALOPHILIC) MICROORGANISMS GROW IN HYPERSALINE ENVIRONMENTS WITH MULTIPLE EXTREME CONDITIONS. AMONG HALOPHILES THE MOST EXTREMOPHILIC ARE THE HALOARCHAEA WHICH ARE OF ADDITIONAL INTEREST DUE TO THEIR CLASSIFICATION AS MEMBERS OF ARCHAEA THE THIRD DOMAIN OF LIFE. THEIR STUDY IS CONTRIBUTING TO THE UNDERSTANDING OF THE NATURE AND CHARACTERISTICS OF SOME OF THE MOST PRIMITIVE AND ANCIENT MICROORGANISMS ON EARTH AND THEIR POLYEXTREME ENVIRONMENTS IN WHICH THEY EVOLVED. THEY HAVE BEEN ISOLATED FROM EXTREME ENVIRONMENTS LIKE DEEP LAKE ANTARCTICA SALAR DE UYUNI BOLIVIA AND GREAT BASIN DESERTS OF WESTERN USA AND SURVIVE LAUNCHES INTO THE STRATOSPHERE. THESE STUDIES ARE IMPORTANT FOR GUIDING OUR ASSESSMENT OF THE POTENTIAL HABITABILITY OF MARS OTHER PLANETS IN OUR SOLAR SYSTEM AND EXTRASOLAR PLANETS DETECTED IN THE GALAXY. STUDY OF HALOARCHAEAL EVOLUTION FITS INTO NASA'S 2015 ASTROBIOLOGY STRATEGIC PRIORITIES INCLUDING EVOLUTION OF EARLY LIFE AND INCREASING COMPLEXITY AND CO-EVOLUTION OF LIFE AND THE ENVIRONMENT AND EXOBIOLOGY RESEARCH EMPHASIS AREAS OF EARLY EVOLUTION OF LIFE AND THE BIOSPHERE AND BIOSIGNATURES AND LIFE ELSEWHERE.