ASTROBIOLOGY Volume 14, Number 11, 2014 News & Views ª Mary Ann Liebert, Inc. DOI: 10.1089/ast.2014.1227 A New Analysis of Mars ‘‘Special Regions’’: Findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2) John D. Rummel,1 David W. Beaty,2 Melissa A. Jones,2 Corien Bakermans,3 Nadine G. Barlow,4 Penelope J. Boston,5 Vincent F. Chevrier,6 Benton C. Clark,7 Jean-Pierre P. de Vera,8 Raina V. Gough,9 John E. Hallsworth,10 James W. Head,11 Victoria J. Hipkin,12 Thomas L. Kieft,5 Alfred S. McEwen,13 Michael T. Mellon,14 Jill A. Mikucki,15 Wayne L. Nicholson,16 Christopher R. Omelon,17 Ronald Peterson,18 Eric E. Roden,19 Barbara Sherwood Lollar,20 Kenneth L. Tanaka,21 Donna Viola,13 and James J. Wray22 Abstract A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003). Results have also been gleaned from the Mars Science Laboratory (launched in 2011). In addition to Mars data, there is a considerable body of new data regarding the known environmental limits to life on Earth—including the potential for terrestrial microbial life to survive and replicate under martian envi- ronmental conditions. The SR-SAG2 analysis has included an examination of new Mars models relevant to natural environmental variation in water activity and temperature; a review and reconsideration of the current parameters used to define Special Regions; and updated maps and descriptions of the martian environments recommended for treatment as ‘‘Uncertain’’ or ‘‘Special’’ as natural features or those potentially formed by the influence of future landed spacecraft. Significant changes in our knowledge of the capabilities of terrestrial organisms and the existence of possibly habitable martian environments have led to a new appreciation of 1Department of Biology, East Carolina University, Greenville, North Carolina, USA. 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA. 3Altoona College, Pennsylvania State University, Altoona, Pennsylvania, USA. 4Department of Physics and Astronomy, Northern Arizona University, Flagstaff, Arizona, USA. 5New Mexico Tech, Socorro, New Mexico, USA. 6Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, Arkansas, USA. 7Space Science Institute, Boulder, Colorado, USA. 8German Aerospace Center, Institute of Planetary Research, Berlin, Germany. 9Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA. 10Institute for Global Food Security, School of Biological Sciences, Queen’s University Belfast, Belfast, UK. 11Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, Rhode Island, USA. 12Canadian Space Agency, Saint-Hubert, Quebec, Canada. 13University of Arizona, Tucson, Arizona, USA. 14Southwest Research Institute, Boulder, Colorado, USA. 15Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA. 16Department of Microbiology and Cell Science, University of Florida, Merritt Island, Florida, USA. 17Department of Geological Sciences, The University of Texas at Austin, Austin, Texas, USA. 18Queen’s University, Kingston, Ontario, Canada. 19Department of Geoscience and NASA Astrobiology Institute, University of Wisconsin, Madison, Wisconsin, USA. 20University of Toronto, Toronto, Ontario, Canada. 21U.S. Geological Survey, Flagstaff, Arizona, USA. 22School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA. 887 888 RUMMEL ET AL. where Mars Special Regions may be identified and protected. The SR-SAG also considered the impact of Special Regions on potential future human missions to Mars, both as locations of potential resources and as places that should not be inadvertently contaminated by human activity. Key Words: Martian environments— Mars astrobiology—Extreme environment microbiology—Planetary protection—Exploration resources. Astrobiology 14, 887–968. 1. Introduction erations. MEPAG’s 2006 analysis was based on results from Viking, Mars Global Surveyor (MGS), and initial results from ince the beginning of human activity in space science Odyssey (ODY, launched in 2001), Mars Express (MEX, and exploration, there has been an appreciation of the S launched in 2003), and the Mars Exploration Rovers (MER, potential negative outcomes of transferring life from one launched in 2003). Now, however, a new body of highly planet to another. Given the unknown consequences of con- relevant data about Mars exists from both the ongoing surveys tact between two biospheres and the fundamental value of of ODY, MEX, and MER—spacecraft which are still active as studying a possible new life-form in isolation from terrestrial of mid-2014—as well as extensive data from the Mars Re- life, thoughtfulness and caution are warranted. Those ideas connaissance Orbiter (MRO, launched in 2005), the Phoenix are reflected in both the United Nations Space Treaty of 1967 mission (PHX, launched in 2007), and initial results from the (United Nations, 1967) and in the International Council for Mars Science Laboratory (MSL, launched in 2011). In ad- Science’s Committee on Space Research (COSPAR) Plane- dition, valuable research has been conducted since 2006 from tary Protection Policy (COSPAR, 2011), which serves under ground-based, laboratory, analog, and International Space the United Nations treaty as a consensus standard for avoiding Station studies. harmful biological contamination. The ‘‘Special Regions’’ concept is a component of the COSPAR Planetary Protection 1.1. Terminology and definitions Policy for Mars that was derived in 2002 (Rummel et al., 2002). Special Regions are regions ‘‘within which terrestrial The terminology adopted for this study was intended to be organisms are likely to replicate’’ as well as ‘‘any region consistent with the original MEPAG SR-SAG study (Beaty which is interpreted to have a high potential for the existence et al., 2006). Accordingly, the following words are intended of extant martian life.’’ Robotic missions planning to have to have the same meaning as before: direct contact with such Special Regions are given planetary protection categorization IVc, with stringent cleanliness 1.1.1. Propagate. To propagate means to reproduce via constraints on the portions of the mission that could contact cell division, generally accompanied by a biomass increase. such regions. The avoidance of the contamination of Special Other kinds of activity, including cell maintenance, thicken- Regions is also the focus of the ‘‘Principles and Guidelines for ing of cell walls (as one aspect of growth), and mechanical Human Missions to Mars’’ (COSPAR, 2011) that are also part dispersal by eolian processes are not sufficient to indicate of COSPAR’s current policy. propagation. While the original COSPAR definition of Special Regions (Rummel et al., 2002) conveyed the concept in qualitative 1.1.2. Special Regions. COSPAR defines Special Re- terms, its proposed translation into (mostly) quantitative gions as ‘‘a region within which terrestrial organisms are terms was accomplished by a two-step process that occurred likely to replicate’’ and states that ‘‘any region which is in- over the course of 2005–2008. The first step was preparation terpreted to have a high potential for the existence of extant of a technical analysis by a Mars Exploration Program Anal- martian life forms is also defined as a Special Region’’ ysis Group (MEPAG) Special Regions Science Analysis (COSPAR, 2011). At present there are no Special Regions Group (SR-SAG; Beaty et al., 2006); this analysis was carried defined by the existence of extant martian life, and this study out in 2005–2006, with most of the technical information concentrates only on the first aspect of the definition. being of early 2006 vintage. The second step involved CO- SPAR’s development of policy in response to that report. This 1.1.3. Non-Special Regions. A martian region may be two-step process resulted in the acceptance (by COSPAR’s categorized as Non-Special if the temperature and water Bureau and Council) of the current Special Region definition availability will remain outside the threshold parameters by COSPAR at the Montreal Assembly in July 2008. CO- posited in this study for the time period discussed below (see SPAR additionally recommended (Kminek et al., 2010) that Section 1.4: Constraints). All other regions of Mars are des- the quantitative definitions of Special Regions be reviewed on ignated as either Special or Uncertain. a 2-year cycle. This study is the first such review since the 2008 definitions were adopted. 1.1.4. Uncertain Regions. If a martian environment can There were two major reasons for undertaking the review simultaneously demonstrate the temperature and water avail- at this