INSIGHTS INTO THE PAST MINERALOGY & FLUVIAL ACITIVTY OF MARS WITH WATSEN

Tim Tomkinson

S.D.Wolters, A.Hagermann, A.F.Bohman, A.T.Sund, J.K.Hagene and M.M.Grady

Orbital results

Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite (OMEGA) onboard Mars

Express (0.3 - 1 km/pixel)

Targeted CRISM hyperspectral

survey: ~18 m/pixel.

Murchie et al, 2007 - Hot spring deposits at Mauna Kea - colours represent

differentphyllosilicate phases.

VNIR & IR spectrometers

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Identified Phyllosilicates – Fe, Mg and Al bearing smectites, kaolinite, chlorite etc…

Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard Mars Reconnaissance Orbiter (multispectral survey: 100-200 m/pixel)

Geological Martian history

J-P. Bibring et al. 2006

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

WatSen

Instrument design•ATR spectrometer (NEO)•Optical microscope (NEO)•Humidity sensor (OU)•Instrument and Ground Support (Navsys)

Testing•IR database using commercial ATR spectrometer (OU)•Environmental chamber (OU)

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Dimensions of trailing mole: •Diameter 26 mm•Length 158 mm

Mass: 180 gPower average: 1.2 W (peak < 3 W)

Design specifications

IR Source Microscope Optics Microscope sensor

IR sensor

LVF Filter

Ge focusing OpticsDiamond windowSampleGe Collimating Optics

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

ATR spectrometer

•Wavelength Range: 5.5 to 10.8 µm

54 martian analogue samples have been measured

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

The ATR sensor operates by measuring the energy changes that occur to the totally internally reflected infrared beam, upon contact with the sample, from stretching, bending and vibration of intra-molecular bonds. Evanescent wave typically penetrates

to a depth of a few micrometers (μm).

Montmorillonite_3_02.06.07_ATRMontmorillonite_1_02.06.07_ATRMontmorillonite_2_02.06.07_ATR

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Montmorillonite

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Saponite54285_3_02.06.07_ATRSaponite54285_1_02.06.07_ATRSaponite54285_2_02.06.07_ATR

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Saponite

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Spectral results

IR spectra of powdered dry basalt taken with a Fourier Transform Infrared Spectrometer (FTIR) at 295 K and 268 K, and water-saturated basalt at 268 K.

IR spectra of powdered samples of Shergotty, Nakhla and Chassigny, along with a basalt, augite, olivine and dolomite. The spectra were acquired using an ATR at 295 K, and are offset for clarity.

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Optical Microscope•Magnification (centre, edge): 0.5x, 0.33x

•Pixel size: (centre, edge): 7.2x7.2,~11x11 µm

•Field of view (horizontal, vertical): 14.5x8.5 mm

•Resolution (centre, edge): 18, 32 µm

•Pixel count: 1316*1048

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Humidity sensor

Will be used to monitor the moisture in the subsurface

surroundings of WatSen.

Functional tests:• Temperature Range: >-60°C• Pressure: 5 mbar

It should be noted that it is not clear to what extent the moisture in thebore hole will equilibrate with the atmosphere.

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

OU Environment Test Chamber

Variables:• Substrate• Environment

• Water content• Temperature• Pressure• Atmosphere

Measurements from WatSen• Spectra• Images• Humidity

Tests Overview

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Proposed future missions• Marco Polo

•Moon Lightweight Interior and Telecoms Experiment (MoonLITE)

•Instrumented projectiles (seismometer, heat flow probe and volatile detector)•Survive high speed impact ~ 300 m/s•Penetrate surface ~ few metres•An alternative to soft landing•Lower cost and low mass => multi-site deployment mission

•Near Earth Object (NEO) mission

•Lander and orbiter

•VolDet (WatSen) replacing humidity sensors for thermal

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary

Summary

Primary Objective: to detect water within martian soil by measuring humidity and IR spectral characteristics of the subsurface material.

Secondary Objective: to determine the mineralogy and mineral chemistry of near surface soils, and to determine how mineralogy changes with depth.

Phyllosilicate detection – WatSen - Instrumentation – Test plan – Future missions - Summary