PPS05-01

Room:106

Time:May 27 14:15-14:30

Examination of Mission Strategy and Spacecraft System to Study Martian AtmosphericEscape
MATSUOKA, Ayako1∗ ; SEKI, Kanako2 ; TERADA, Naoki3 ; YOKOTA, Shoichiro1 ; YAMAZAKI, Atsushi1 ;ABE, Takumi1 ; IMAMURA, Takeshi1 ; KAWAKATSU, Yasuhiro1 ; FUTAANA, Yoshifumi4 ; HIRAHARA, Masafumi2 ;ISHISAKA, Keigo5 ; KUMAMOTO, Atsushi3 ; KURIHARA, Junichi7 ; NAKAGAWA, Hiromu3 ; SAKANOI, Takeshi6 ;TAGUCHI, Makoto8 ; OGOHARA, Kazunori9
1

ISAS/JAXA, 2 STEL, Nagoya Univ., 3 Dept. Geophys., Grad. Sch. Sci., Tohoku Univ., 4 IRF, Sweden, 5 Toyama Pref. Univ.,
Planet. Plasma Atmos. Res. Cent., Tohoku Univ., 7 Cosmosciences, Hokkaido Univ., 8 College of Science, Rikkyo Univ.,
9
School of Engineering, The Univ. of Shiga Prefecture
6

The atmospheric escape from Mars is considered to be closely associated with the evolution of the Martian atmosphere as wellas the existence of the water on Mars. We are now investigating a project to study the global feature and the physical processof the atmospheric escape from Mars. It is expected to consist of two orbiters; the mother satellite is aimed to make in-situ
observation of plasma and thin atmosphere at about 150 km altitude, and atmospheric imaging at the apo-apsis of 3RM altitude.
The daughter satellite is the solar-wind monitor. We are planning to make simultaneous observation of the atmospheric escapeby the interaction with the solar wind by these two satellites. Now we are examining the quantitative measurement targets tofully understand the Martian atmospheric escape. At the same time, the sorts and performance of scientific instruments on theseorbiters are examined. And furthermore, the preliminary spacecraft design, orbit design and mission plan to achieve the scientificgoal are investigated.
Keywords: Mars, Planetary atmosphere, Solar wind, Planetary Magnetic Field, Plasma

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PPS05-02

Room:106

Time:May 27 14:30-14:50

MARS PLATE-TECTONIC-BASEMENT
DOHM, James1∗ ; MARUYAMA, Shigenori2 ; MIYAMOTO, Hideaki1 ; NIIHARA, Takafumi1
1

UMUT, 2 TiTech

Introduction: The Hadean-age-equivalent (>4.0 Ga) Martian basement complex has heretofore been difficult to characterize.
This is due to extensive modification by the Late Heavy Bombardment and subsequent impacts, as well as chemical alterationof the primary rocks (including weathering rinds, clay minerals, Al/Fe oxides/hydroxides, sulfates, and evaporite deposits). Obscuration of a felsic basement includes erosion of the terrain predominantly through wind and water activity, as well pervasive
mantling by wind- (e.g., aeolian), water- (e.g., fluvial, alluvial, colluvial, glacial, periglacial), and volcanic- (airfall deposits, lava
flows materials, fine-grained volcanic spherules transported by wind) related materials.
Yet, unlike the Hadean rocks that have been obliterated on Earth, the Hadean-age-equivalent ancient Martian basement is stillpreserved. This is because an Earth-like phase of Mars, including an active dynamo and hypothesized plate tectonism, terminatedsufficiently early in its evolutional stage to archive early Mars rocks, early solar system history, and possibly evidence of earlylife. New evidence for plate tectonism includes a systematic, spatial arrangement of landforms, referred to as the Claritas subduction zone region that is strikingly similar to the plate-tectonic-modified landscapes of the western US that resulted from plate
migration and subduction, including the subduction of the denser mafic Farallon Plate beneath the lighter felsic North American
Plate. We will present this finding and additional evidence for a Hadean-age-equivalent phase of plate tectonism on Mars and its
implications. For greater details see [1].
[1] Dohm, J.M., Spagnuolo, M.G., Williams, J.-P., Viviano-Beck, C.E., Karunatillake, S., Alvarez, O., Anderson, R.C.,
Miyamoto, H., Baker, V.R., Fairen, A., Mahaney, W.C., Hare, T.M., Robbins, S.J., Niihara, T., Yin, A., Judice, T., Olsen,N., Maruyama, S., 2015. The Mars Plate-Tectonic-Basement hypothesis. 46th Lunar and Planetary Science Conference, Abstract 1741.

Keywords: mars, plate tectonics, basement, felsic

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PPS05-03

Room:A03

Time:May 28 09:00-09:15

Early Evolution of Martian Atmosphere and Hydrosphere: Constraints from Isotopic
Compositions
KUROKAWA, Hiroyuki1∗ ; KUROSAWA, Kosuke2 ; USUI, Tomohiro3
1

Dept. of Phys., Nagoya University, 2 Planet. Explor. Res. Ctr., Chiba Institute of Technology, 3 Dept. of Earth & Planet. Sci.,
Tokyo Institute of Technology

Current Mars has a cold and dry surface environment with a small amount of water-ice observed at the polar regions (Christensen, 2006). On the contrary, increasing evidence suggests that the early Mars once sustained a warm climate with a large
amount of liquid water (e.g., Di Achille & Hynek, 2010). Though impact erosion and thermal/nonthermal escape are accepted
to have possibly contributed to the loss of the early atmosphere and hydrosphere (Lammer et al., 2008), the timing of the escapeand the relative importance of each process are poorly constrained.
The thermal/nonthermal escape induces isotopic fractionation that leaves behind heavier isotopes in the atmosphere and hydrosphere, whereas the impact erosion removes a fraction of atmosphere without the isotopic fractionation. The early evolutionof the atmosphere and hydrosphere is constrained by the isotopic data of the martian meteorite Allan Hills 84001 (ALH 84001),
which records a high hydrogen isotope ratio (D/H = ∼2-4 times the Martian primordial water) of 4.1 Ga surface water (Boctor etal., 2003; Greenwood et al., 2008). The high D/H ratio suggests that a larger amount of water was lost during the first 0.4 billion
years than the later periods by the thermal/nonthermal escape (Kurokawa et al., 2014). On the other hand, the isotope ratios ofnoble gases at 4.1 Ga show unfractionated values, implying that the atmosphere was lost after 4.1 Ga (Mathew & Marti, 2001;
Jakosky & Phillips, 2001). Estimates of atmospheric nitrogen isotope composition of ALH 84001 varies in previous studies(Miura & Sugiura, 2000; Mathew & Marti, 2001).
We calculate the evolution of the total amounts of the atmosphere and hydrosphere and their isotopic compositions individually, considering the impact erosion and thermal/nonthermal escape. First, we calculate the evolution of the total atmosphericpressure due to the impact erosion using a stochastic bombardment model (Kurosawa et al., 2013). We calculate the surface
age using the cumulative number of impacts and an empirical curve obtained from the lunar craters (Chyba, 1991). The erosion
efficiency at each impact is calculated using a modified sector blow-off model (Vickery & Melosh, 1990). The momentum ofan expanding silicate vapor is calculated using the entropy method (e.g., Ahrens & O’Keefe, 1972; Kurosawa et al., 2012) andthermodynamic data for forsterite (Sekine et al., 2012). Second, we calculate the evolution of the isotope ratios of the minor
volatile elements (D/H, 15 N/14 N, 38 Ar/36 Ar) due to the thermal/nonthermal escape following the evolution of the total pressure.
We assume the escape rates of the ion pick-up, sputtering, and photochemical escape given by Jakosky et al. (1994) and Pepin(1994) for oxygen, nitrogen, and argon. Hydrogen is lost by the Jeans escape whose escape rate is regulated by the loss of oxygen(Liu & Donahue, 1976). The fractionation factor of hydrogen is assumed to be 0.016 (Krasnopolsky et al., 1998; Krasnopolsky
2000). We adapt the fractionation factors of other species (nitrogen and argon) tabulated in Jakosky et al. (1994).
The total pressure decreases in several orders of magnitude during the first several hundred million years which corresponds tothe heavy bombardment period, whereas the degree of pressure reduction is relatively insignificant after this period. The nitrogenand argon isotope ratios start to increase as the total pressure decreases. On the contrary, the D/H ratio increases independentlyof the total atmospheric pressure because the major reservoir of hydrogen is the hydrosphere.
Comparing our results with the isotopic data at 4.1 Ga recorded in the martian meteorite ALH 84001, we propose a scenariothat the loss of atmosphere and hydrosphere had proceeded before 4.1 Ga. An efficient isotopic fractionation of atmosphericnitrogen and noble gases due to the thermal/nonthermal escape started after the impact erosion of the thick early atmosphere
during the heavy bombardment period.
Keywords: Mars, atmosphere, hydrosphere, isotope, impact, atmospheric escape

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PPS05-04

Room:A03

Time:May 28 09:15-09:30

Spectral observation of mesospheric CO2 ice clouds in the Martian mid-low latitude using
PFS onboard Mars Express
SATO, Yuki1 ; KASABA, Yasumasa1∗ ; AOKI, Shohei2 ; GIURANNA, Marco2 ; NAKAGAWA, Hiromu1 ;KURODA, Takeshi1 ; SATO, Takao M.3
1

Tohoku Univ., 2 IAPS/INAF, 3 ISAS/JAXA

Mars is the only known planet where CO2 ice clouds can be observed. CO2 , main component of Martian atmosphere, cancondense and form ’CO2 ice clouds’ in the coldest region; in the troposphere above polar night and in the mesosphere aroundequator. CO2 ice has narrow spectral emission peak feature at 4.3 um. Unfortunately, polar cloud in the lower altitude is below
thick atmosphere and this spectral feature can not be detected by strong CO2 gas absorption. However, mesospheric cloud in
low-mid latitude is enough high. Dayside nadir observation of OMEGA aboard the Mars Express spacecraft first detected suchfeature.
In this study, we attempted to detect the spectral feature of mesospheric CO2 ice clouds in low-mid latitude at 4.3 um band by
Planetary Fourier Spectrometer (PFS) onboard Mars Express. In this wavelength, its spectral resolution is ˜1,000, about 10 times
higher than that of OMEGA. It enables us to resolve the spectral features of CO2 ice clouds with enough resolution to estimate
their particle size comparing with synthetic spectra. We confirmed that PFS could detect this spectral profil on the orbits where
OMEGA detected CO2 ice clouds. In the PFS spectral resolution, we identified two spectral types, i.e., ’single-peak case’ at 4.25
um and ’double-peak case’ at 4.25 and 4.28 um, which were not resolved by OMEGA.
Based on this confirmation, we statistically surveyed the CO2 ice features in all PFS data in 2004-2014 which covers MY
27-32. We identified 272 single-peak cases and 9 double-peak cases. Spatial and seasonal distributions of CO2 ice clouds agreed
with the previous studies. In spatial distribution, CO2 ice clouds were detected in the latitude range of 20 degS to 20 degN andthe longitude range of 100 degW to 30 degE and around 170 degE. In seasonal variation, almost all of CO2 ice clouds weredetected just after spring equinox (Ls : 0-30 deg).
In these samples, the spectral peak in the single-peak case and the first peak of double-peak case was centered at 4.252 um.
From this observed feature, we derived the typical particle size of CO2 ice clouds by the comparison with the synthetic spectra
derived by a radiative transfer model with the assumption that cloud particles were made of pure CO2 ice and had sphericalshape. Refractive index of CO2 ice is from experimental one. Although the observed single-peak feature was reproduced by
the model, the peak wavelength appeared at ˜4.27 um, shifted to 0.02 {Y=mu}m longer position than the observed one. Suchshift of the peak position could not be reproduced by various particle parameters, including radius, size variance, and column
density. In addition, the synthetic spectra could not reproduce the double-peak structure observed by PFS. We proposed threepossible cases to explain these discrepancies; (1) the uncertainty of the refractive indices, (2) non-spherical particle shape, and(3) different core material in CO2 ice. For (1), we simply assumed that the model refractive index could be shifted 20 nm toward
shorter wavelength. After that, we got satisfied agreement between the observed and model spectrum. Based on the matching ofboth spectrum, effective radii of observed CO2 ice cloud were constrained in the range between 0.63 to 1.0 um. This is the firstquantitative estimation of the CO2 ice clouds using 4.3 um feature of CO2 ice. The effective radii obtained by our model follows
the line of CRISM observation (0.5-2.0 um) but slightly small compared with that of previous works. For (2) and (3), they canpotentally produce double-peak features observed by PFS. It means that non-spherical haze with a core material might be actual
characteristics of the Martian mespheric CO2 ice cloud.

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PPS05-05

Room:A03

Time:May 28 09:30-09:45

Cyclic step on ice: experiments and theoretical study aiming to spiral troughs on Mars’
North Polar ice cap
YOKOKAWA, Miwa1 ; IZUMI, Norihiro2∗ ; NAITO, Kensuke3 ; YAMADA, Tomohito2 ; GREVE, Ralf4
1
3

Faculty of Information Science and Technology, Osaka Institute of Technology, 2 Faculty of Engineering, Hokkaido University,
University of Illinois, at Urbana-Champaign, 4 Institute of Low Temperature Science, Hokkaido University

The spiral troughs observed on the Mars’ North Polar Layered Deposits (NPLD) contain a detailed stratigraphic record of
surface processes in Mars’ recent polar history. SHARAD radar data showed that the troughs have migrated towards the northduring the accumulation of the uppermost ˜600 m of NPLD, and Smith et al. (2013) concluded that the spiral troughs should bea kind of cyclic steps formed by katabatic wind blowing on the ice cap. Cyclic steps are spatially periodic bedforms where eachwavelength is delineated by an upstream and downstream hydraulic jump. They migrate upstream keeping the same wavelength.
Cyclic steps have been reported from various environments on the Earth, such as fluvial and deep-sea settings, and in various bed
materials, such as bedrock, non-cohesive sediments, and cohesive sediments. While the formation of cyclic steps on bedrock or
beds composed of sediment is a mechanical process, the formation of cyclic steps on ice is not only a mechanical but thermodynamic process. There have not been many studies on the thermodynamics of the formation of cyclic steps on ice to authors’knowledge. In this study, we conducted a series of experiments on the formation of cyclic steps on ice due to flowing water overit. In addition, we performed a linear stability analysis of the water-ice interface and show that the formation of cyclic steps canbe explained by the results of the analysis in part.
The experiments were conducted in the cold chamber owned by the Institute of Low Temperature Science, Hokkaido University. We have conducted 8 cases of experiments by the use of the experimental apparatus that consists of a flume, a cooling systemof the flume, and a circulating system of water. We kept the ice temperature to be below zero degrees in Celsius, the flowing
water temperature to be from 0.2 to 2 degrees in Celsius, and the room temperature to be about 5 degrees in Celsius. As a result,
it is found that trains of steps are formed when the Froude number is larger than a value around unity. Those steps are associatedwith hydraulic jumps, and steps mostly migrate in the upstream direction. Based on these diagnoses and the morphologic feature,these steps can be evaluated as cyclic steps on ice bed.
We performed a linear stability analysis on instability of interface between flowing water and ice, and made physical explanation of the formation of cyclic steps. According to the results of the analysis, the interface becomes unstable when the Reynolds
number is relatively large under the condition that the heat flux from ice is sufficiently weak, that is to say, the temperature at
the ice bottom is not so low, and the ice thickness is sufficiently large. In addition, the unstable region in the wave number Reynolds number plane hardly depends on the heat transfer coefficient of air normalized by the heat diffusivity of water and theflow depth.
We compared the results of experiments and the analysis, and found that the experimental data fall on the unstable region bothin the wave number - Reynolds number plane and the wave number - Froude number plane where interfacial instability takes
place. This indicates that at least the experimental results are consistent with the analytical results. The critical Froude number
derived from the analysis is approximately unity in the range of small slope angles, and slightly increases with the slope angle.
In the experiments, cyclic steps are not formed in the case of the Froude number smaller than unity while cyclic steps are formed
in all the case of the Froude number larger than unity. In terms of the critical Froude number, the experimental results are well
explained by the analysis.
Keywords: cyclic step, ice, spiral troughs

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PPS05-06

Room:A03

Time:May 28 09:45-10:00

Life search plan on Mars surface and the significanceYAMAGISHI, Akihiko1∗ ; SATOH, Takehiko2 ; MIYAKAWA, Atsuo1 ; YOSHIMURA, Yoshitaka3 ; HONDA, Hajime4 ;SASAKI, Satoshi5 ; IMAI, Eiichi4 ; USUI, Tomohiro6 ; MIYAMOTO, Hideaki7 ; FUJITA, Kazuhisa8
1Tokyo Univ. Pharm. Life Scie., Dep. Applied Life Scie., 2 ISAS/JAXA, 3 Tamagawa Univ., 4 Nagaoka Inst. Tech., 5 Tokyo Univ.
Tech., 6 Tokyo Inst.Tech., 7 The Univ. Tokyo, 8 JAXA

The view of active Mars has been emerged based on the recent findings of the exploration and high-resolution imaging of Mars.
The finding includes the Recurring Slope Linear (RSL), where the presence of liquid water is most provable. We are planning totest the view of Mars still active and the presence of current life at the most promising place on the Mars surface.
Thought the 1970’s Viking mission reported the detection of catalytic reaction that could be attributed to life (Levin and Straat1977), negative conclusion was made based on the level of organic compound lower than the detection limit. In 2000’s, theresults of Viking mission was reevaluated(Glavin, et al.2001; Navarro-Gonzalez, 2006), and found that the detection limit oforganic compound, 106 -107 cells/g soil, is not sufficient to detect the microbes with lowest microbe density (i.e. deep see water,
Atacama desert, Antarctic desert soil) 104 cells on Earth.
SAM (Sample Analysis at Mars) onboard the NASA’s Rover MSL (Mars Scientific Laboratory) Curiosity has detected organic
compound in the Gale Crater, though its origin is not clear. SAM detected chlorinated methane 4 micro gram/g Martian soil
(Ming et al. 2014). If we assume the amount corresponds to the total organic carbon and the ratio of total organic carbon andmicrobes similar to those at Atacama Desert (Connon et al. 2007), the 4 x 104 cells/g soil is expected for the Gale Crater.
We developed the fluorescence microscope system to detect the microbe. We are targeting the most provable place with liquidwater. We will use fluorescence microscope and fluorescence pigment that can detect organic compounds and can differentiate itfrom organic compounds surrounded by membrane, the latter being most provably ”cells”. We named the system Life Detection
Microscope, LDM.
If we were to find life on Mars surface, life will be examined, and totally new knowledge of life extending the knowledge ofterrestrial life will be obtained, transforming the Biology to New and so to speak Real Biology.
In the next stage of exploration, genetic material DNA and amino acid will be analyzed. If the Martian life uses genetic
material different from DNA or the DNA different from ACGT, it is life emerged independently. If the life on Mars turned out topossess the same DNA (ACGT) as terrestrial life, phylogenetic analysis of Martian life will be conducted. The Martian life may
be unrelated to terrestrial life, if there is no homology between genes of the two life forms. If there is homology between genes,
phylogenetic tree will tell us whether the life emerged only on Earth and transported to Mars, or the life emerged only on Marsand transported to Earth. In the last case, life may have emerged on the third celestial body and transported to Earth and Mars.
If the life could not be found by LDM, the current scheme on origin of life has to be reconsidered. A. If life emerged both on
Mars and Earth, what is the condition supported life only on Earth. B. If life emerged only on Earth, what is the critical factor thatprevented the emergence of life on Mars. C. If life emerged only on Mars, why it is extinct on Mars. D. If the life emerged on thethird celestial body, what prevented the settling of life on Mars. Prebiotic conditions on Mars and Earth have to be reevaluated.
References
1. Levin G. V. and Straat., P. A. 1977, J. Geophys. Res., 82, 4663-4667.
2. Glavin, D. P. et al. 2001, Earth Planet Sci. Lett. 185, 1-5.
3. Nabarro-Gonzalez, R. et al. 2006, Proc. Natl. Acad. Sci. 103, 16089- 16094.
4. Ming, D. W. et al. 2014, Science, 343, DOI:10.1126/science.1245267
5. Connon, S. A et al. 2007, J. Geophys. Res. 112, G04S17, doi:10.1029/ 2006JG000311

Keywords: Fluorescence microscope, Fluorescence pigment, Origin of life, Phylogenetic tree

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PPS05-07

Room:A03

Time:May 28 10:00-10:15

Life-Detection Microscope (LDM) onboard 2020 Mars Mission MELOS
SATOH, Takehiko1∗ ; YAMAGISHI, Akihiko2 ; MIYAKAWA, Atsuo2 ; SASAKI, Satoshi3 ; FUJITA, Kazuhisa1 ;LDM, Team1
1

JAXA, 2 Tokyo University of Pharmacy and Life Science, 3 Tokyo University of Technology

Life-Detection Microscope (LDM) is the primary science payload onboard the MELOS rover which we propose to launch in2020. LDM is designed to achieve a sensitivity (104 cells per gram soil) which is two orders of magnitude better than the Viking
Lander experiments. The strategy to achieve this high sensitivity includes: 1) cells, if exist, are dyed with SYTO24, PI, andCDMA pigments; 2) the fluorescence from dyed cells (excited with blue light at 488 nm) is imaged with 1 um/pixel resolution;3) the field of view in one image is 1 mm2 ; and 4) 2 mm3 volume of Martian soil is scanned.
LDM consists of 3 components: Sample-Handling System (SHS), Fluorescence Microscope (FluM), and Driver and Data
Processor (DDP). To receive soil sample from the robotic arm of the rover, one ”empty” sample container is selected and is
moved to the sample inlet position (X and Y movements in SHS). After receiving the soil sample, the dye is injected and then thecontainer lid is closed so that the rapid evapolation of the solvent under the atmospheric pressure (6 hPa) of Mars is avoided. A
set of regolith and dust images in white light are acquired before ”fluorescence” mode is started. In ”fluorescence” mode, a set ofimages with different focal depths (0 to 0.1 mm) are acquired at each of 20 (X, Y) positions, achieving scan of desired volume (2mm3 ) of soil sample. The images are examined for suspicious objects and small sections of images which include such objects,
if any, are stored in the rover’s data recorder for later downlink to the earth.
We will report progress in development of LDM and will discuss the operation strategy of LDM in the mission period on Mars.
Keywords: Mars, Life, Microscope, Fluorescence, Soil, Rover

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PPS05-08

Room:A03

Time:May 28 10:15-10:30

Exploration of carbonate and clay mineral on Mars: clues for climate, atmosphere, anddeep hydrosphere of early Mars
SEKINE, Yasuhito1∗ ; USUI, Tomohiro2 ; SHIBUYA, Takazo3 ; KADOYA, Shintaro1 ; CHO, Yuichiro4 ;KAMEDA, Shingo4 ; TACHIBANA, Shogo5 ; WATANABE, Sei-ichiro6
1

University of Tokyo, 2 Tokyo Institute of Technology, 3 JAMSTEC, 4 Rikkyo University, 5 Hokkaido University, 6 Nagoya University
High-resolution remote sensing data of Mars Noachian terrains show the widespread existences of clay minerals formed bygroundwater circulations [1]. This suggests that hydrothermal activity in deep crusts may have played a major role in hydrological cycles on early Mars [1], which is contrast to those on current Earth and might be similar to those occurred on Europa or
Enceladus [2, 3]. To date, however, Mars rovers have performed analyses at outcrops of sedimentary rocks formed mainly by
open water activity [4, 5]. Lack of knowledge on the nature of groundwater activity obscures us to understand a whole picture ofhydrological cycles, aqueous geochemistry, and habitability on early Mars.
Recent observations and models suggest that there are some locations where groundwater upwelled on the surface of earlyMars [6]. These include one of the deepest craters on Mars, McLaughlin Crater, which exhibits layered deposits of carbonatesand Mg-Fe-bearing phyllosilicates on the crater floor [6]. The proposed mineral assemblages suggest the occurrence of geochemistry between CO2-bearing, alkaline groundwater and ultramafic rocks [6]. This implies that the outcrops of McLaughlin
Crater could serve as a unique window to look into the nature of groundwater activity and its interactions with the atmosphere ofearly Mars.
Here we propose a Mars rover mission to perform geological and geochemical analyses of outcropped carbonates and clay
minerals on McLaughlin Crater. Geological observations of the outcrops would determine the formation processes of these layered deposits. The aqueous geochemical conditions (e.g., the composition, redox state, and pH of groundwater, water-rock ratio,
and temperature) would be determined based on results of detailed chemical and mineralogical compositions of the outcrops.
These observational data enable us to constrain redox potentials of groundwater, which could support deep biosphere on Mars.
In addition, we can estimate the partial pressure of atmospheric CO2 equilibrated with the groundwater. This, in turn, meansthat our mission will be able to answer the long-standing question whether early Mars had a dense CO2 atmosphere, which will
provide critical insights into the habitable zone [7] and formation process of terrestrial planets in the solar system and beyond.
[1] Ehlmann et al., 2011, Nature, 479, 53. [2] Hsu et al., 2015, Nature, in press. [3] Zolotov and Kargel, 2009, in Europa, Univ.
Arizona Press. [4] Squyres et al., 2004, Science, 306, 1709. [5] Vaniman et al., 2014, Science, 343, 1243480. [6] Michalski etal., Nature Geosci., 6, 133. [7] Kasting et al., 1993, Icarus, 101, 108.

Keywords: Mars, exploration, geochemistry, carbonate, hydrothermal activity, atmosphere

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PPS05-09

Room:A03

Time:May 28 10:30-10:45

MEMS pirani pressure sensor for the Mars Organic Molecule Analyzer ( MOMA) of the
ExoMars Mission
ADACHI, Tomoko1∗ ; SOUTHARD, Adrian2 ; BROWN, Gary3 ; JOHNSON, Christopher3 ; GONNSEN, Zach4 ;RIEMANN, Lisa5 ; AREVALO, Ricardo3 ; PINNICK, Veronica3 ; DANELL, Ryan3 ; BRINCKERHOFF, William3 ;MAHAFFY, Paul3
1
3

Dept. of Physics, Catholic University of America, Washington, DC, 2 University Space Reserch Association, Columbia, MD,
NASA Goddard Space Flight Center, Greenbelt, MD, 4 MICROTELL LLC., Winterville, NC, 5 AS and D Inc., Greenbelt, MD

The Mars Organic Molecule Analyzer, MOMA is a collaborative mission by European Space Agency, and NASA Goddard
Space Flight Center. MOMA is a key analytical instrument aboard the ExoMars rover, set to launch in 2018. The rover will
search for past and present evidence of martian life The twin rovers Spirit and Opportunity have confirmed that water was longstanding on the surface of Mars long ago. The Curiosity rover found aromatic, organic compounds in the mudstone at the bottomof a possible ancient lake. Mars Science Laboratory scientists found that chlorobenzene was formed during the reactions inside
the Sample Analysis (SAM) instrument from martian chlorine and carbon during the heating of perchlorates known to be present
in martian soil. The ExoMars rover will sample martian soil/rock at depths of up to 2 meters, deeper than any instrument before
it. The rover collect the sample and analyze them by MOMA. The MOMA has two operation modes: Gas Chromatograph-Mass
Spectrometry (GC-MS); and Laser Desorption-Mass Spectrometry (LD-MS). (Please see the image) LD-MS employ laser desorption ionization to avoid the need to heat the sample, thereby preventing perchlorate reactions, which complicate identificationof compounds in the sample. GC-MS will identify the chirality of organic molecules, improving understanding of how thesemolecules were formed.
The MEMS (microelectro-mechanical system) pirani pressure sensor is a critical component that will be used to ensure the ion
trap mass spectrometer0s time sensitive operation in the LD-MS mode. It employ a high voltage for ionizations, and knowing
the pressure of the MS chamber by miliseconds time scale is critical. The pressure data is used for the telemetry of the MS
operation. Also the pirani pressure sensor has a critical function that pressure changes as a discontinuous inlet and pump work
together to sample the Mars atmosphere in LD-MS mode. It also has to work at ambient temperatures varying from -20 to 80
degrees Celsius and be calibrated for both carbon dioxide for sampling martian atmosphere and helium during use of the gas
chromatograph. The MEMS pirani sensor provides better than 0.1 mtorr accuracy over the critical pressure range from 1 mtorr
to 0.1 mtorr and has a usable pressure range from 0.1 mtorr to 0.1 torr. This paper will focus on the characterization of the pirani
sensor and its electrical interface and modeling ideas of a next generation of MEMS pressure sensor for future planetary andspace missions.
Keywords: Robotic Rover Mission on Mars, MEMS pirani pressure sensor, Organic molecule analysis, Ion Trap, Laser Desorption Mass Spectroscopy, Gas Chromatograph Mass Spectroscopy

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PPS05-10

Room:A03

Time:May 28 11:00-11:15

Possible landing sites on Mars for an in-situ K-Ar dating by future Japan’s Mars rover
mission
MIURA, Yayoi N.1∗ ; CHO, Yuichiro2 ; MOROTA, Tomokatsu3 ; MIYAMOTO, Hideaki4 ; USUI, Tomohiro5 ;KAMEDA, Shingo2 ; SUGITA, Seiji6 ; OKAZAKI, Ryuji7
1

ERI, Univ. Tokyo, 2 Rikkyo Univ., 3 Nagoya Univ., 4 Univ. Museum, Univ. Tokyo, 5 Tokyo Inst. Tech., 6 Univ. Tokyo, 7 Kyushu
Univ.
Mars shows a variety of surface features affected by geologic processes. Though the crater-based dating has estimated surface
ages, ranging from nearly 4.5 Ga age to recent, the absolute ages have not been determined for Martian samples except a mudstone at Gale crater by the Curiosity rover mission (4.21 ± 0.35 b.y.) and meteorites that come from somewhere on Mars. The
authors have been developing an in-situ K-Ar dating system for future Japan’s landing mission on Mars (e.g., Cho et al., 2014,2015). In this paper, aims of the chronologic investigation using the system onboard a Mars rover/lander and appropriate landingsites are discussed.
Studies of impact crater densities present three representative eras for geologic history of Mars; Noachian, Hesperian andAmazonian (e.g., Tanaka, 1986). Abundant water should have existed early in Martian history (likely the Noachian and a part of
the Hesperian), but most of them disappeared. In order to understand habitable environment, climate changes and atmosphere
evolution of Mars it is important to determine the absolute ages of geologically-well-defined Noachian/Hesperian samples. Considering crater chronology, mineralogy, geological setting and engineering requirements (altitude, latitude and thermal inertia),
we propose three regions that are covered by Hesperian volcanic rocks as candidates of chronologic investigation; Syrtis Major
Planum, north-east side of Tharsis and peripheral area of Amazonis Planitia. Crater counting based on CTX and HRSC images
applied to five specific areas in Syrtis Major provides ages ranging in 3.0 - 3.6 Ga (where the model by Hartmann and Neukum,2001 is adopted). Among which, two areas reveal resurfacing evidences; the crater frequency gives older ages of 3.7 - 3.8 Ga
for the sizes >1 km in diameter and the thickness of the younger lava (for the sizes <1 km) is estimated to be ~ 40 m. Syrtis
Major, having gentle slope and less abundant dust, is a highly recommended region for the landing site. Further information suchas local morphology and shock and alteration phenomena should also be considered.

Keywords: Mars, Mars exploration, K-Ar dating, chronology, Hesperian, Syrtis Major

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PPS05-11

Room:A03

Time:May 28 11:15-11:30

Remote sensing of Martian surface events by Electro-magnetic and Sonic Wave observation aboard a Martian rover
YAMAMOTO, Masa-yuki1∗ ; SATO, Mitsuteru2 ; ISHISAKA, Keigo3 ; TAKAHASHI, Yukihiro2 ;KAMOGAWA, Masashi4 ; OGOHARA, Kazunori5 ; MIYAMOTO, Hideaki6
1

Kochi University of Technology, 2 Hokkaido University, 3 Toyama Prefectural University, 4 Tokyo Gakugei University, 5 Universityof Shiga Prefecture, 6 The Unversity of Tokyo

In order to detect many kinds of surface events on Mars, a small instrument with electro-magnetic and sonic wave receivers
has been considered as one of the remote sensing equipments onboard a future Japanese Mars rover.
By combining the observation of 3-axes electro-magnetic waves and sonic waves, precise identification of the events source
coordinates with respect to the rover position can be realized because of the phase difference of each detecting waves and large
difference of the speed of light (c) and sound (Cs). The observation plan has been discussed as a remote sensing instrument for
distribution measurement of Martian discharge events (like lightning and thunder on the Earth), however, it can also be applied
for the Martian surface studies as a very unique equipment, moreover, the size, weight, and power resources for the instrument issmall and suited for installing on the small rover system planned to land the Mars.
On the Mars, as a result of the most recent research activities mainly by the NASA MSL (Opportunity) rover and several
orbiters, many possible surface events like fluid motion on the edge of craters, so called RSL (Recurring Slope Lineae) seen asa narrow dark-tones streak activities depending on the Martian season change. Moreover, some scientists reported the possible
regions of gas eruption from the surface of the Mars.
Here, we will introduce the recent progress of the instrumentation design and environment test results of the electro-magnetic
and sonic wave observation instruments for the future exploration by landing explorer on the Mars.
Keywords: Mars, Electro-magnetic wave, Sonic wave, Surface events, Rover, Remote sensing

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PPS05-12

Room:A03

Time:May 28 11:30-11:45

Characterization of Martian Regolith: Toward 2020s Mars Exploration Missions
USUI, Tomohiro1∗ ; YAMAGISHI, Akihiko2 ; SATO, Takehiko3 ; MIYAMOTO, Hideaki4 ; KAMEDA, Shingo5 ;FUJITA, Kazuhisa3 ; SEKINE, Yasuhito4 ; TACHIBANA, Shogo6 ; WATANABE, Sei-ichro7
1
5

Tokyo Institute of Technology, 2 Tokyo University of Pharmacy and Life Science, 3 ISAS, JAXA, 4 The University of Tokyo,
Rikkyo University, 6 Hokkaido University, 7 Nagoya University

Mars once had surficial liquid water (paleo-ocean/lake) and shows a promising sign of current subsurface water/ice. The
existence of hydrosphere and cryosphere makes Mars the unique accessible habitable planet next to the Earth. The water-rockinteraction between the lithosphere and hydrosphere/cryosphere through the history of Mars has produced a variety of surface
rocks (regolith) containing sheet-silicates, phosphates, sulfates, and carbonates, which are closely linked to climate and thepotential for life on Mars. This study characterizes the physico-chemical properties (chemical composition, mineral abundance,
reflectance feature, and geometric distribution) of Martian regoliths. We further present a way to leverage the database on Martian
regoliths as a tool for interpreting remote sensing analyses by onboard instruments (e.g. Life Detection Microscope) for Mars
exploration missions in 2020s.
Keywords: Mars, regolith

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PPS05-13

Room:A03

Time:May 28 11:45-12:00

Geological implications of landing-site candidates of the MELOS mission
MIYAMOTO, Hideaki1∗ ; KOMATSU, Goro2 ; USUI, Tomohiro3 ; DOHM, James1 ; HEMMI, Ryodo1 ;NIIHARA, Takafumi1 ; LUYUAN, Xu1 ; KAMEDA, Shingo5 ; SATOH, Takehiko6 ; YAMAGISHI, Akihiko4
1

University of Tokyo, 2 IRSPS, 3 TiTech, 4 Rikkyo University, 5 ISAS/JAXA, 6 TUPLS

Ancient Mars is now considered to have had environment somewhat similar to that of Earth in terms of the existence of large
bodies of water, a wide range of surface oxidation states, appearances of variety of chemical components potentially building
blocks of life, and a magnetic field. Endogenic activities have continued even until very recently, and recent water-related geological features indicate prolonged existence of an aquifer system, where a habitable environment may exist for a significant
period of time. Occasional releases of volatiles from such an aquifer system may ultimately account for the inconclusive result(not unambiguous denial) of metabolism-detection instrument onboard Viking landers. Japanese MELOS Mars mission is proposed to carry an in-situ life detection package onboard a 150kg-sized rover, as well as a visible-near IR camera and a Ground
Penetrating Radar system to perform geological investigation.
Because the primary purpose of the MELOS mission is to perform the Life Detection Microscope (LDM) instrument experiment, which is designed to detect less than 10ˆ4 cells in 1 gram clay, orders of magnitude higher than previous attempts performed
by Viking landers, landing-site candidates of the MELOS mission are selected in terms of the possibility of the existence of nearsurface water and recent geological and hydrological activities including the possible release of volatiles (specifically, relatively
high water activity (Aw>0.6), a relatively higher maximum environmental temperature (T>250), and an existence of gradientsof free energy). We propose Melas chasma as a prime candidate because of the existence of recurring slope lineae (RSL), wheretraces of possible liquid water and seasonal flow have been reported, as well as the fact that Valles Marineris provides the best
exposures of the ancient geologic history of Mars. The latter includes: (1) Melas chasma being the widest and deepest partof the Valles Marineris; (2) it being connected to the outflow channels; (3) Interior Layered Deposits (ILDs) showing various
sulfates deposits, suggesting the existence of abundant past water; and (4) various phyllosillicates having been detected among
the canyon units. As for the current volatile release, we find Tharsis/Elysium Corridor region is the best candidate, which shows
evidence of long-lived water enrichment and recent geologic activity, including recent venting that could bring materials fromthe subsurface to the surface environment. In this talk, we examine the morphologic characteristics of these features and discussgeological context of the candidate landing sites.

Keywords: Mars, MELOS, life detection, water, current activity

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PPS05-14

Room:A03

Time:May 28 12:00-12:15

Meteorological Instruments of Mars EDL
OTOBE, Naohito1∗ ; HASHIMOTO, George2 ; SENSHU, Hiroki3 ; NAKAYOSHI, Makoto4 ; KURIHARA, Junichi5
1

Fukuoka Univ, Faculty of Science, 2 Department of Earth Sciences, Okayama University, 3 Planetary Exploration ResearchCenter, Chiba Institute of Technology, 4 Tokyo University of Science, Fuculty of science and technology, 5 Graduate School of
Science, Hokkaido University

Mars Exploration plan is started for Landing at 2020.
Landing to Mars surface, Moving with Rover, and Searching Life itself.
We, Melos Meteorological Sub Working group, also proposal some instruments.
Those are including Thermometer, Anemometer, Barometer, Radiation Meter, Radiation Thermometer and Navigation camera,
LIDAR, Particle counter.
We call first 5 instruments basic instruments set, and last 3 instruments Dust sensors.
This presentation is to introduce developing and testing sate of progress of these sensors.
[Thermometer] We use 3 different color thermos-sensors. Difference of radiative absorption makes difference temperature of
sensor. Sensible heat is calculated it’s difference. And 1 thermo-sensor is heated, for calculating wind velocity.
[Barometer] This instruments is in TRL-5. Using Impedance of Cristal
Oscillator is changing with friction of atmosphere.
If we know the air components, the friction is a function of Pressure, so it works as a barometer.
[Radiation Thermometer] Thermocouple seeing to the surface of Mars. It can measure Surface temperature.
[Anemometer] Same as Thermometer. But we use 4 couple of sensor, for calculating wind direction.
[Navigation Camera] This is a BUS-equipment to monitor around the rover. We use this camera to detect dust-devils.
[LIDAR] Counting the back scatter of LASER, We obtain a sum of cross-section of dusts along LASER path. Resolution
along path is around 1m.
[Particle Counter] Small In-situ sensor, mechanism is similar to LIDAR.
Counting the scatter of light within very small (0.5x2x1mm) region.
This can measure number of particle for separated to 5 bin of size.
State of developing is very different each other, some is only discussion,
The others are tested with Mars like environment, Mars Environment Simulation Chamber settled in PERC/Chiba Institute ofTechnology).

Keywords: Mars, Meteology

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PPS05-15

Room:A03

Time:May 28 12:15-12:30

Assessment of Mars surface environment for a exploration program: application of CReSS
to Martian atmosphere
SUGIYAMA, Ko-ichiro1∗ ; ODAKA, Masatsugu2 ; NAKAJIMA, Kensuke3 ; TAKAHASHI, Yoshiyuki O.4 ;OTOBE, Naohito5 ; NISHIZAWA, Seiya6 ; HAYASHI, Yoshi-yuki4 ; HASHIMOTO, George7 ; HASEGAWA, Kouichi8 ;SAKAKIBARA, Atsusi8 ; TSUBOKI, Kazuhisa91ISAS/JAXA, 2 Hokkaido University, 3 Kyushu University, 4 Kobe University, 5 Fukuoka University, 6 RIKEN Advanced Institutefor Computational Science, 7 Okayama University, 8 chuden CTI, 9 Nagoya University
A Mars surface exploration program is now planned by space engineering and planetary science communities in Japan. To
support designing the landing module and observation instruments and ensure safety mission operation, evaluation of plausible
range of meteorological conditions at proposed landing site is required. For mesoscale assessment of Mars surface environment,
we are now trying to apply ”Cloud Resolving Storm Simulator (CReSS)” (Tsuboki and Sakakibara, 2002) to Martian atmosphere.
CReSS is a numerical model based on quasi-compressible system (Klemp and Wilhelmson, 1978). To apply CReSS to Martian
atmosphere, radiative transfer scheme (Takahashi et al., 2006) used by planetary atmospheric general circulation model DCPAM(Takahashi et al. 2012) is introduced. The surface topography, albedo, and thermal inertia are adopted from Mars Global Surveyor observation data. The terrestrial calendar included in CReSS, which defines the length of year, month, hour, and minute,is modified to be suitable for Mars’ rotation and orbital period.
To examine the model performance, we perform some idealized numerical experiments without the surface topography and effects of large-scale circulation. At first, we perform comparing experiments to the result of one-dimensional radiative-convective
calculations (DCPAM-1D) with almost same experimental setting, and find that the simulated diurnal variations of surface temperature and heat budget at the surface are consistent with those of DCPAM-1D. Next, we perform experiments with solar
radiative condition at the landing sites of NASA’s rover, Spirit and Opportunity. We find that the simulated vertical temperature
profiles near the surface in daytime are consistent with the data of NASA’s rover if using mixing length of sub-grid scale turbulence parameterization given by Deardorff et al. (1980) which is commonly adopted in previous studies (e.g. Spiga et al., 2010).
Following the idealistic experiments mentioned above, we begin to perform more realistic numerical experiments at proposed
landing sites. In the experiments, the surface topography and effects of large-scale circulation are considered. In order to consider
the effects of large-scale circulation, simulation data of DCPAM is used as initial and boundary conditions.
In this presentation, we show outline of our numerical model and some results of numerical experiments.

Keywords: Martian atmosphere, planetary exploration, numerical modeling, cloud resolution model

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PPS05-16

Room:A03

Time:May 28 12:30-12:45

Scientific significance of sample return from Martian moons
TACHIBANA, Shogo1∗ ; WATANABE, Sei-ichiro2 ; SEKINE, Yasuhito3 ; USUI, Tomohiro4
1

Dept. Natural History Sciences, Hokkaido University, 2 Division of Earth and Planetary Sciences, Nagoya University, 3 Dept.
Earth and Planetary Science, The University of Tokyo, 4 Dept. Earth and Planetary Sciences,Tokyo Institute of Technology

The asteroid explorer Hayabusa2 began a six-year round trip in December 2014 to return surface samples of a near-Earthcarbonaceous-type asteroid 1999 JU3 following Hayabusa’s successful return of the first asteroid samples to Earth. Hayabusa2
will arrive at 1999 JU3 in mid-2018, and fully investigate and sample the asteroid at three locations during its 18-month stay.
The samples from 1999 JU3 will be delivered to the Earth in December 2020. Primitive small bodies are the evolved remnantsof planetesimals that were the building blocks of planets, and detailed on-site observation by a spacecraft and analyses of returnsamples will provide direct evidence of planetesimal formation and dynamical and chemical evolution of the solar system.
Moreover, such small bodies could have delivered volatile components to rocky planets in the early solar system.
Sample return missions to primitive small bodies such as main belt asteroids, Jovian Trojan asteroids, icy satellites, and comets
require a timescale of decades, and it is important to plan short-term exploration missions to primitive bodies. Here we proposea sample return mission to Martian moons (Phobos and Deimos), of which characteristics resemble those of C-type or D-type
asteroids. If they are captured main-belt asteroids, their surfaces have not been heated as much as near-Earth asteroids are.
Martian moons are thus likely to preserve more primitive materials such as ice, which is one of possible constituents responsible
for their low bulk-densities. If they are remnants of building blocks of Mars, the returned samples will provide us the first anddirect information on the formation of Mars, the bulk chemistry of Mars, and the isotopic compositions of volatile elements as
a starting point of Martian environmental evolution. Isotopic compositions of returned samples will be a key to address thisissue on the origin of Martian moons. Surface regolith of Martian moons may contain ejecta from the Martian surface and/or
the escaped Martian atmosphere, and the returned samples may enable us to put constraints on the crustal and environmental
evolution of Mars. The remote-sensing observation of Martian atmosphere and surface from the spacecraft can also be done
from the spacecraft. In this presentation, we will describe the outline and scientific rationales of the sample return mission from
Martian moons.
Keywords: Mars, Satelite, Phobos, Deimos, Sample return

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PPS05-P01

Room:Convention Hall

Time:May 27 18:15-19:30

Magnetic anomaly mapping on the Martian surface with the SVM method
YAMAGUCHI, Masao1∗ ; TSUNAKAWA, Hideo1 ; TAKAHASHI, Futoshi2
1

Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2 Faculty of Sciences, Kyushu University

Although Mars has no global magnetic field of the core dynamo origin at present, strong magnetic anomalies of the crustal
origin have been detected by the satellite observation (Acuña et al., 1998). All of the Martian magnetic fields mapped so far werenormalized at relatively high altitudes, 400 km using magnetometer data (Acuña et al., 2001; Connerney et al., 2005), and 185
km by electronreflectometer data (Lillis et al., 2008). These magnetic anomalies often show systematic patterns such as magnetic
stripes. Connerney et al. (2005) reported several lineated magnetic anomalies of ∼25-degree wavelength in the Meridiani region,
suggesting possible existence of plate tectonics in the early Mars. As described above, magnetic anomalies may have information
about tectonic processes of the ancient Mars associated with magnetization acquisition. Thus it is important for understanding
the Martian evolution to compare the Martian magnetic anomalies with surface features, that is, topography, geology and soon. Regarding the comparison purpose, the previous maps normalized at high altitudes are inappropriate due to poor spatial
resolution. The magnetic field observed by a satellite at a 400 km altitude is effectively a convolution of the neighboring crustal
magnetic fields within ∼800 km in diameter (∼13 degrees on Mars). In addition, it is difficult to detect fine structures of thecrustal magnetic fields at high altitudes due to rapid attenuation of short wavelength components with respect to altitude. To
overcome such difficulties we have applied the surface vector mapping (SVM) method, which is originally developed to map
the lunar magnetic anomalies at the surface (Tsunakawa et al., 2014), to those of Mars. To check applicability, the regional
SVM method has been tested for the Terra Sirenum region in the southern hemisphere. Based on the radial components at thesurface inferred by the SVM method, we reproduce the magnetic fields at 200 km altitude to show good consistency with theprevious maps (Purucker et al., 2000). The SVM map of radial components shows elongated magnetic anomalies of ∼3-degree
wavelength which is much shorter than that in the previous map (Connerney et al., 2005). We also apply the regional SVM
method to the Meridiani Planum near the equator, where plate tectonics was suggested by Connerney et al. (2005). Although a
few elongated magnetic anomalies are detected on the SVM map, the overall patterns of magnetic anomalies are so complicatedthat it seems difficult to find something to support the Martian plate tectonics.
Keywords: Mars, magnetic anomaly, Martian surface

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PPS05-P02

Room:Convention Hall

Time:May 27 18:15-19:30

Interannual analyses of the longitudinal distributions of Martian water ice clouds, dust
and temperature by MRO-MCS
NOGUCHI, Katsuyuki1∗ ; YAMAYA, Makiko1 ; FUJIO, Asami1 ; KURODA, Takeshi2 ; HAYASHI, Hiroo3
1

Nara Women’s Univeristy, 2 Planetary Plasma and Atmospheric Research Center, Tohoku University, 3 FUJITSU FIP CORPORATION
We investigated the longitudinal distributions of dust and clouds with temperature and their correlations in the Martian atmosphere by using Mars Reconnaissance Orbiter Mars Climate Sounder (MRO-MCS) multi-year measurements. Results show thatthe water ice clouds concentration around Hellas Planitia (30-60S, 50-100E) decreased during late autumn and early spring in thesouthern hemisphere (Ls=70-110 deg), and temperature and the dust concentration in the same region increased simultaneously.
The results suggest that the heatup by dust sublimated water ice clouds to decrease the concentration of water ice clouds. The
decrease of water ice clouds and the corresponding behaviors of temperature and dust were clearly observed in three Mars Years(MY29-31), suggesting the strong interannual repeatability.
Keywords: Mars, water ice clouds, dust, temperature, MRO, MCS

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PPS05-P03

Room:Convention Hall

Time:May 27 18:15-19:30

Local time dependence of dust in the Martian atmosphere by the PFS onboard Mars Express
OSONO, Takuma1∗ ; KASABA, Yasumasa1 ; AOKI, Shohei2 ; GIURANNA, Marco2 ; NKAGAWA, Hiromu1 ;SATO, Takao3 ; SATO, Yuki1 ; KURODA, Takeshi1
1

Tohoku University, Department of Geophysics, Planetary Atmosphere Physics Laboratory, 2 Istituto di Astrofisica e Planetologia
Spaziali (IAPS), Istituto Nazionale di Astrofisica (INAF), 3 Institute of Space and Astronautical Science (ISAS)

This study tries to evaluate the local time dependence of dust optical depth using Planetary Fourier Spectrometer (PFS) onboard the Mars Express (MEx) in the Martian Year (MY) 27-30.
Dust in the Martian atmosphere is a major heat source by the absorption of solar radiation, and affects the thermal structureand global scale circulation. Thermal Emission Spectrometer (TES) onboard Mars Global Surveyer (MGS) have revealed theseasonal and latitudinal variation of dust optical depth (e.g., Smith et al., 2004). Mars Reconnaissance Orbiter (MRO) haveshown its vertical structure (Heavens et al., 2014). However, due to the lack of the coverage of local time by previous spacecraft,its diurnal variation is still under debate.
Only a few previous studies reported the diurnal variations of dust optical depth. Formisano et al. (2001) investigated the
local time (LT) dependence of dust optical depth using infrared interferometer Spectrometer (IRIS) onboard the Mariner 9. They
showed that the dust optical depth decreased from 1.0 at 7.5 LT to 0.4 at 12.5 LT, and increased to 1.0 at 17.5 LT. The originof its variation was suggested as dust devil. Martin and Tamppari. (2007) used Infrared Thermal Maping (IRTM) on board theViking orbiters, and demonstrated that the dust optical depth gradually decreased from 10 LT to 16 LT. They also suggested that
there was no correlation to dust devil occurrence.
We analyzed the local time dependence of dust optical depth by PFS aboard MEx. Dust optical depth was retrieved in the 9 µm
wavelength band (Grassi et al., 2005). The MEx has an advantage of wider local time coverage than that of previous spacecraft.
This paper shows a tentative results in MY 27-30. We selected quiet days, and excluded the data sets associated with active days
including global dust storm (ex. Ls 260o - 360o in MY28).
We focused on the periods from Ls 0o - 180o which showed little seasonal variations of dust opacity. The local time dependence was investigated for every Ls 20o step. The region that local dust storm occurs frequently (latitude: >60o ) was not used.
In the initial analysis by the PFS data, the dust optical depth increased in afternoon, from 13 LT to 20 LT, as Formisano et al.
(2001). And, there are some seasons which showed the decrease of dust optical depth from 9 LT to 16 LT, but not all. In the PFS
team, dust opacity data set is now revision by a new method and criteria for the reduction of retrieval error. Since local time and
Ls is coupled in MEx data sets, we will also validate the PFS result with simultaneous other spacecraft observations at different
LT. In the meeting, we will present the renewed analysis results.

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PPS05-P04

Room:Convention Hall

Time:May 27 18:15-19:30

Algorithm for identifying fluorescently-labeled single-celled organisms and minerals in
microscopic images
DEMURA, Hirohide1∗ ; KANEDA, Yuya1 ; MOMOCHI, Terumasa1 ; MATSUMOTO, Takeyuki1 ; MIYAMOTO, Hideaki5 ;YOSHIMURA, Yoshitaka4 ; MIYAKAWA, Atsuo2 ; SATOH, Takehiko3 ; YAMAGISHI, Akihiko2
1

The University of Aizu, 2 Tokyo University of Pharmacy and Life Science, 3 Institute of Space and Astronautical Science, Japan
Aerospace Exploration Agency, 4 College of Agriculture, Tamagawa University, 5 The University Museum, The University ofTokyo
We’ve made a study for an algorithm of identifying single-celled organisms as Life on Mars. We’ll report its results.
Keywords: Mars, Microscope, Algorithm, Life, Single-celled organisms, fluorescently-labeled

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PPS05-P05

Room:Convention Hall

Time:May 27 18:15-19:30

Behavior of glycerol solution under Martian environment
NISHIZAWA, Masataka1 ; FUKADA, Kakeru1 ; SATOSHI, Sasaki1∗ ; MIYAKAWA, Atsuo2 ; SATO, Takehiko3 ;IMAI, Eiichi4 ; HONDA, Hajime4 ; YOSHIMURA, Yoshitaka5 ; YAMAGISHI, Akihiko2
1
4Tokyo University of Technology, 2 Tokyo University of Pharmacy and Life Sciences, 3 Japan Aerospace Exploration Agency,
Nagaoka University of Technology, 5 Tamagawa University

Microscopic detection of possible bacterial cells on Mars using life detection microscope (LDM) is planned in MELOS (Mars
Exploration for Living Organisms) project. One candidate solution for the fluorescent dyes is 66.7% glycerol. Under Martian
atmosphere, evaporation of water from the solution is expected. Estimation of evaporation flux and resulting behaviors (masschange, cooling, convention, bubbling etc.) should be essential for the design of sample handling system (SHS) and imaging
procedure. Observation of solution mass change, convection, bubbling of the solution sealed in the 7 hPa chamber was performed.
Convection was analyzed from the thermographic images. Measurement of water activity was also performed with and without
the model sand samples. Following results were obtained: (1) Glycerol concentration changed after water evaporation. Freezing
temperature should, therefore, increase and solution freezing might occur. The amount of evaporated water depended on the holediameter of the sealing cap, indicating that even incomplete sealing was effective. (2) The solution showed heterogenious density
distribution as a result of evaporation. Convection, which was infavorable for the image capturing, due to the nonuniform density
was observed. (3) Sand attached-water showed various water activity, which changed according to the material and size of thesand particles.
The 66.7% glycerol solution containing fluorescent dyes also successfully stained cultured bacteria, organic materials, andmicroorganisms in Marian soil simulant and natural environmental samples. We also developed the formula and conditions topreserve the fluorescence pigment before and after landing on Mars and during the microscopic observation.
Reference
M. Nishizawa et al. (2013) Fluorescent Dye Handling System for MELOS1 Life Detection Microscope. In International
Astrobiology Workshop 2013, p. 47. LPI Contribution No. 1766, Lunar and Planetary Institute, Houston.
Keywords: MELOS, LDM, glycerol solution

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