Atmospheric Water Experiment for a Small Orbiter at Mars (AWESOM) Paul Hayne 1, Matt Siegler 1,2, Imran Mehdi 1, Erich Schlecht 1, Goutam Chattopadhyay 1, and David Paige 3 1 Jet Propulsion Laboratory – Caltech, 2 Planetary Science Institute, 3 UCLA

Overview Possible liquid-water features recently observed on Mars indicate potentially habitable environments Submillimeter (microwave) spectroscopy is a powerful technique for observing water vapor and constraining its concentration and isotopic composition Recent developments at JPL have led to miniaturized instruments compatible with cubesats

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McEwen et al., 2013 Ojha et al., 2014 “Recurring slope lineae” (RSL)

Hypotheses: 1.Spring and summer temperatures get warm enough to melt subsurface (salty) ice 2.Deliquescence draws H 2 O vapor out of the atmosphere gradually, until droplets form

Could Evaporation at RSL Generate H 2 O Plumes? Mumma et al., 2003 (Not water)

Seasonal (background) Water Vapor Smith, 2002  Continuous coverage at all local times needed in order to detect (or rule out) water plumes Time

Why Microwaves? MIRO (Rosetta)

Why Microwaves?  Can measure water vapor at ~10 -6 pr-  m!

Heterodyne Instruments (JPL has a long and distinguished history) Earth Science: Atmospheric science, temperature and pressure profiling, cloud physics and dynamics, ozone depletion, wind velocity etc Astrophysics: Study galaxies far away, star formation, star decay, D/H ratio measurement, water detection, C+ detection, HD detection, etc HIFI on Herschel MLS on Aura MIRO on Rosetta (sending data right now!!) STO Planetary Science: Planetary atmospheres and the search for water and life signatures, sounding, etc

Heterodyne Technology Development (1 of 2) JPL continues to lead with MDL fabricated diode MMICS and silicon micro-machining that are robust and enabling Integrated Receiver Front-ends provide compact foot-print and lower mass W-band input waveguide RF input waveguide LO waveguide SHM Tripl er Complete Receiver in silicon package 2-11 GHz IF output GHz mW GHz Integral feedhorn 20 mm Low-parasitic membrane MMICs

Heterodyne Technology Development (2 of 2) Infusion of advanced CMOS technology Enhance functionality with lower mass and power 28 GHz – 35 GHz Frequency Synthesizer for Local Oscillator (LO) Total Power Consumption: Less than 100 mW A Full 2.0 GS/s spectrum analyzer chip in advanced 65nm CMOS is developed in collaboration with UCLA. Integrated 7b digitizers, offset and interleaving calibration functions, clock management system and vector accumulation. 512 channel quadrature output with integrated USB 2.0 controller.

Reduce volume, mass, and power consumption! Investigate simplified testing and calibration schemes Approx. 20 cm SHM Tripler PA X3 Sextupler X6 VCO Antenna > 50x Reduced Volume size Challenges for Cubesat Accommodation

Possible Discoveries Water vapor available for deliquescence? Water vapor plume after RSL activity? Diurnal water vapor variations Water vapor isotopic abundances (origins?) Vertical winds, surface temperatures, pressures

Summary Possibility of liquid H 2 O activity on present-day Mars is real, but controversial Water vapor measurements could resolve debate Microwave spectroscopy is an ideal technique for measuring H 2 O vapor abundance and composition Highly-compact JPL microwave spectrometers are being developed for cubesats