[P-PS02_28AM2] Mars

[PPS02-07] 火星生命探査顕微鏡を用いた生命探査のための着陸地点候補

*宮本 英昭¹、臼井 寛裕²、小松 吾郎³、Dohm James²、新原 隆史⁴、小熊 みどり¹、佐藤 毅彦⁵、山岸 明彦⁶ (1.東京大学、2.東京工業大学、3.国際惑星科学研究大学院、4.国立極地研究所、5.宇宙科学研究所、6.東京薬科大学)

キーワード：火星, 生命探査, 顕微鏡, 着陸地点, 水

Mars explorations of past decades indicate that ancient Mars had environment somehow similar to that of Earth. Existence of large bodies of water, chemical building blocks of life, a wide range of oxidation states, and a magnetic field indicate that Mars would have been habitable. Recent studies of microbes in extreme environments show that some terrestrial microbes have possibilities for surviving and proliferating under the current martian environment, if these are placed in some specific conditions such as with sufficient shield from UV light (attained only at more than several centimeters below the surface) and with the existence of gradients of free energy. Such environmental conditions likely exist at some specific locations even the present Mars. For this reason, we are developing a new instrument called LDM (Life Detection Microscope), which is designed to detect less than 10^4 cells in 1 gram clay, orders of magnitude higher than previous attempts performed by Viking landers. To maximize the chances of the detection of organisms, the landing sites should be carefully selected in terms of the possibility of the existence of near-surface water, as well as recent geological activities and release of volatiles. Traces of possible liquid water flow have been reported at a number of locations including those recognized as the recurring slope lineae, seasonal flows on slopes of several craters, and anastomosing slope streaks. These are proposed to be the result of small and continuous seeps of subsurface brine water, which could persist for a longer period providing a habitable environment. In this talk, we examine the morphologic characteristics of these features and discuss their origins in the line of geological contexts for selecting appropriate landing sites for the LDM instrument.