From Siberia to Mars
Because Mars is so similar to Earth, planetary scientists looking for answers to questions like these often use analogous environments on Earth to help them design future Mars missions.  Such terrestrial sites, however remote, are still much more accessible than Mars.  Field studies in such places give us a chance to test and refine instruments and procedures, develop overall concepts and collect baseline data to compare with actual results from Mars.  Perhaps the best terrestrial analogue to the martian permafrost lies in northeastern Siberia.  Freezing conditions have persisted here for over 3 million years.  Although young by martian standards, these are among the oldest continuously frozen localities on Earth.  They also hold something remarkable:  not only organic residues, but also large numbers of viable bacteria (up to 100 million per gram of frozen soil), preserved for 3 million years in ice.
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NASA Ames Research Center, USA.
Friedmann
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Meyer
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D001105:Archaea; D003081:Cold Climate; D018534:Earth, Planet; D018559:Exobiology; D005118:Extraterrestrial Environment; D005580:Fossils; D007391:International Cooperation; D018535:Mars; D012800:Siberia; D014586:USSR; D014481:United States