E. R. Kursinski (U. Arizona) Dual Satellite Chemistry and Climate

Dual Satellite Chemistry and Climate Mission Concept From the Mars Astrobiology & Climate Observatory (MACO)

E. R. Kursinski (U. Arizona)

M. Richardson, C. Newman (Caltech) J. R. Lyons (UCLA) W. Folkner, J. T. Schofield, D. Wu (JPL) D. Ward, A. Otarola, C. Walker (U. Arizona) D. Hinson (SETI) M. Gurwell (Harvard-Smithsonian CfA) P. Bernath (U. York, UK) K. Walker (U. Toronto) J. McConnell (U. York, Canada) Y. Moudden (U. Colorado) J. Barnes, D. Tyler (Oregon State) F. Montmessin, J.L. Bertaux, O. Korablev (CNRS Service d'Aéronomie) F. Forget (Laboratoire de Météorologie Dynamique) P. Elosegui (Institut de Ciències de l'Espai)

Nov 4, 2009 Mars Decadal Survey Mtg Pasadena Mars Atmosphere Group Science Questions Addressed here (from Mischna et al., 2009) Dust: What is the vertical distribution of dust during local/regional/global dust events? What causes initiation, growth and decay of global dust events? Why do some storms remain small while others grow to global scale?

H2O: How does water vapor vary on diurnal, seasonal & annual cycles & what factors contribute? Is the water cycle a “closed” system or is there net transfer of water between hemispheres? What role does the subsurface play & what is the surface vapor flux on these timescales? What is the vertical distribution of water in the atmosphere, both as vapor and ice? Trace gas chemistry: What are the distribution & abundance of trace gases? What are the sources & sinks? Do they indicate current of past presence of life? What roles do subsurface activities play in controlling trace chemistry? Is the composition consistent with photochemical models? What processes (homogeneous or heterogeneous) are missing? Upper atmosphere: How do processes in the upper atmosphere of Mars affect the lower atmosphere, and vice versa? How well do numerical models reflect these processes? Past climates: Are current erosion processes consistent with a substantially thicker early Martian atmosphere? Could surface liquid water have been sustained during much of Martian history? What are the isotopic ratios of common gases? What does this tell us about atmospheric erosion rates and the possibility of life, past or present? Is there an observable, secular or periodic change in Martian climate (e.g. temperature, atmospheric opacity, water content) over extended periods? Winds: What is the 3-D wind structure of the Martian atmosphere from the surface to upper atmosphere? What is the strength of the global circulation? How do these change diurnally, seasonally and interannually? Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 2 How do we answer these questions? Upper atmosphere: many addressed by MAVEN (2013)

Lower and middle atmosphere: We propose a dual satellite orbiting mission (DSM) concept that uses – mm-wavelength satellite to satellite (sat-sat) occultations as well as solar occultation and thermal emission at mm wavelengths – Thermal IR aerosol sounder – Near-IR Solar occultations (SO).

Unique feature of this mission concept is satellite to satellite occultations – Yield a combination of sensitivity, accuracy and vertical resolution 1 to 2 orders of magnitude beyond radiometers – 2 ~counter-rotating satellites can provide ~30,000 globally distributed, near-entry probe quality profiles each Martian year – Profile near-surface environment, answering and strongly constraining most of the key lower and middle atmosphere Mars science questions  (previously thought unachievable from orbit). – Mission is designed as global field campaign to tightly constrain processes and monitor changes in behavior

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 3 Mission Rationale

Achieving the desired global perspective likely requires an orbiting mission. – Well equipped landed network powerful complement to orbiting mission (Rafkin et al. 2009), but cost will likely limit scope: number of locations, instrument capabilities

Challenge: Probing the near-surface environment to answer majority of Mischna et al. questions are tied to near surface environment. Examples: DUST: (1) how dust storms are initiated, evolve and decay, (2) why some grow to global scale while others remain local. WATER: (3) the exchange of water with surface and subsurface reservoirs (4) Is there a net transfer of water from one hemisphere to the other TRACE GASES: (5) sources and sinks, (6) interactions with subsurface, (7) role of heterogeneous chemistry.

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 4 Mission Rationale (cont’d)

Answering these questions requires profiling dust, water, trace gases, clouds, winds, turbulence and their meteorological context that i) are distributed globally ii) extend routinely right to the surface, i) independent of dust (not possible at IR and shorter wavelengths) ii) Independent of surface emission variations (not possible for thermal emission measurements at any wavelength), iii) few hundred meter or better vertical resolution and high precision (<10%) to resolve the boundary layer variations, iii) separate the seasonal and diurnal cycles achieved with rapidly precessing, high inclination orbits, iv) Sample with sufficient density to address the key science questions Simultaneously profile different variables to constrain interrelationships: 1. Dust, water and trace gases for heterogeneous chemistry 2. Winds, turbulence and dust to determine how dust storms are initiated 3. Winds, turbulence, dust, water and trace constituents to determine transport and constrain location of localized sources. Measure isotopes to constrain 1. present processes and sources 2. past climates and evolution of Mars.

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 5 Dual Satellite Mars Chemistry & Climate Mission Concept Mission concept to characterize  Trace gas chemistry of Mars

 Climate: water, dust, CO2 and wind cycles  Focused on revealing signatures of processes Instrument Suite  Solar occultation near-IR spectrometer  Millimeter-wave Limb Sounder (MMLS) – Satellite-to-satellite occultations, solar occultations, limb emission  Thermal IR Ice & Dust Sounder (MIDS) co-pointed w/ MMLS + IR & visible aerosol particle size & surface frost + Context imager Rapidly precessing, high inclination orbits Proposed as Scout in 2006.  Global coverage for solar occultations in ~44 sols  Received highest science rating  Full diurnal coverage for MMLS & MIDS in 44 sols  Risk: 2 satellites in Scout budget

Sees thru dust Nov 4, 2009 SeeD edustcadal Survey Mars Panel - Caltech Kursinski, et al. 6 mm-wave Satellite to Satellite Occultations Temperature

 Vertical resolution: 60m at 320-360 GHz (1 mm wavelength) X-band RO  Profile to surface: insensitive to dust & surface emissivity MGS  Temperature: <0.5K (0-50km); Pressure: 0.1%

 H2O(0-50 km) concentration & mixing ratio: 1-3%; better Relative humidity: 4-6%, with HDO(0-20 km) 3%, averaging  Profile ppb: H2O2 5; H2CO 0.1; O3 4; SO2 1; OCS 0.3;  Winds: LoS from CO,13CO, C17O, C18O <2.5 m/s Constituents Balanced winds from pressure gradients  Turbulence: via scintillations (“twinkling of a star”)  Coverage: Global; Full diurnal coverage in 44 days ⇒30,000 ~entry probe quality profiles/Mars year ⇒Limb emission 200,000 profiles/yr (between sat-sat occ) ⇒Sol. occ. provide spectroscopic calibration

Temperature variations Amplitude variations Self calibrating, LoS winds Turbulence differential absorption

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 7 Occultation Technique Summary

 An occultation occurs when orbital α motion of Sat1 and Sat2 cause Sat1 to ‘see’ Sat2 rise or set across the limb  This causes the signal path between Sat1 and Sat2 to slice through the atmosphere which acts as a lens that occultation bends the signal path and attenuates the signal via absorption geometry Delay(t) => bending angle(z) => refractivity(z) => density(z) => P(z) => T(z)

" dn 1 bending & 1 ) *(a) da # $ = d$ = 2a dr n(r01 )= exp$' ! ! !(3) 2 2 2 (4) ( 2 2 n dr $ + a a ' a ! rt n r # a % 1 1 " Forward relation Inverse relation x=# x dr dx absorption a=" dx 1 da d$ da $ (a) = k dl = 2 k k = # 1/ 2 2 2 ! 2 2 " " % dr a a da x=a x ! a = 0 a=a0 (a # a0 ) Absorption(t) => optical depth(z) => extinction coef(z,P,T) => constituent(z)

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 8 AATTOOMMMMSS//MMAACCOO DDiiffffeerreennttiiaall AAbbssoorrppttiioonn

Measure occultation signal amplitude simultaneously at 2 or more frequencies, – One closer to line center to measure absorption – Calibration tone farther from line center to ratio out unwanted effects

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 9 Brief History of Mars Dual Satellite Occultation Concept

 GPS-LEO occultations began in 1995, now producing 2,000 daily occultations, – recommended by Earth Decadal Survey of 2007 as operational mission for weather & climate  Earth: Began to develop cm & mm-wave occultation concept in 1998 – as 1998 ESSP mission proposal (not selected) – Selected in 1998 as “ATOMS” NASA IIP  MACO one of 10 Scout concepts given seed money in 2000  Developed concept for 2002 Scout AO but did not fit in budget cap  Developed and submitted proposal for 2006 Scout AO – Received highest science rating – Viewed as high risk => Category 3 rating  Earth: Aircraft-aircraft occultation demonstration selected as NSF MRI in 2007 with NASA providing aircraft time  Proposed MIDP in 2008: not selected as no ride existed for the instrument

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 10 Operational ECMWF system September to December 2008. Averaged over all model layers and entire global atmosphere. % contribution of different observations to reduction in forecast error.

Forecast error contribution (%) GPS RO has significant impact (ranked #5 among all observing systems) in reducing Courtesy: Carla Cardinali forecast errors, despite the small number of and Sean Healy, ECMWF soundings. 22 Oct. 2009 Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 11 Optimized Occultation Geometry The MACO Satellite Orbits

MACO-Lo 70o inclination, 400×450-km orbit. MACO-Hi 55o inclination, 435×1734-km orbit. - High inclinations: daily pole-to-pole coverage. - High rate of precession provides

- Separation of diurnal and seasonal cycles

- pole to pole solar occultation coverage every 44 days (=1/15 year). - The two orbits have identical precession rates to maintain stable occultation coverage over time (both prograde). - Low altitude, short period orbits provide 42 sat-sat occultations per day. - Having 2 different orbital periods yields (desirable) random coverage - These 2 particular orbits provide evenly distributed coverage over the diurnal cycle across the globe - >1 Martian year mission duration for full seasonal sampling - Orbital altitudes > 400 km avoid planetary protection issues

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 12 MACOMACO CoverageCoverage

Table D.1-1: MACO sampling density vs. observation type. 44-day Precession Daily Annual Cycle Observation Type Cycle Prof. Coverage Profiles Coverage Profiles Coverage MACO-Hi to MACO-Lo 42 Global 1850 Global, Diur- 28000 Global, Diurnal, Sea- Occ nal sonal Solar Occ Near-IR and 10 2 latitudes 440 Global 7000 Global, Seasonal mm Limb Emission, IR 750 Global 33000 Global, Diur- 5x105 Global, Diurnal, Sea- nal sonal Limb Emission, mm 360 Global 16000 Global, Diur- 2x105 Global, Diurnal, Sea- nal sonal

MACO radio occultation latitude vs. longitude coverage over a 55 day period ~Martian month MACO movie

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 13 So what can we do with this observing system tool kit…

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 14 Probing the near-surface environment from orbit Simultaneously profile mm-wave variables and dust & ice via thermal IR

Many science questions are tied to understanding near surface environment  Energy: exchange between surf & atmo; separate radiative & sensible heat fluxes  Water: exchange between surface & atmosphere, ID subsurface reservoirs via D/H ratio, transfer between hemispheres via flux & D/H  Dust: lifting, storm trigger events & evolution  Chemistry: tying plumes back to their sources, role of heterogeneous chemistry Answers: near-surface measurements of constituents & dynamics, global & diurnal coverage  Global field campaign: Build up profiles of regional diurnal sampling ~15 times per year to infer exchange of water vapor, energy and momentum between atmosphere and surface  Orbital periods can be chosen to produce random coverage or repeating pattern such as twice per day at ~20 global locations radiosondes on Earth

night day night day

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 15

DDiiuurrnnaall CCyyccllee ooff SSuurrffaaccee EExxcchhaannggee

 Surface exchange is key part of methane, water and energy cycles  Thin atmosphere makes partitioning of radiative and sensible exchange quite different from Earth  Radio occultation provides the sensitivity and vertical resolution to measure diurnal cycle of exchange from space

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 16

Heterogeneous Chemistry

Explanation for rapidly loss of methane & oxidized surface?  Dissociative electron attachment (DEA) reactions – Involves generation of electric fields via saltation and dust lifting followed by ion recombination chemistry How do we evaluate whether it is true  Probe near surface environment looking for predicted enhancement in H2O2 (~1,000) as a function of dust, winds, turbulence and H2O (as limiting source molecule) Solution

 Sat-sat occultations precisely profile H2O2, H2O, winds and turbulence down to surface with ~100 m vertical resolution, independent of dust, full diurnal coverage  Co-pointed MIDS profiles dust with 2 km vert. res.

 Look into the dusty areas, measure H2O2 enhancement and determine how important heterogeneous chemistry is and how it works

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 17 Plume Source Reconstruction Tucson Desire: in situ surface measurements & return to Earth day night day Placing lander near a source requires knowing source location & its extent => depends on accuracy of measurements and models. – Near surface winds and mixing are complex – Satellite sampling of a region every half sol: 10 m/sec uncertainty grows to 400 km location uncertainty – Model uncertainty is likely as good as the observational constraints on winds and mixing at key scales Sat-sat occultations profile LoS winds to the surface to 2

m/sec and turbulence with <100 m vert. resol: – critical for improving the models and to steer reconstruction of plume via data assimilation

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 18 Trace Gases

 Near-IR solar occultation spectrometer is focus of trace gas survey, sampling more gases and is more sensitive than mm-wave  Mm-wave complements providing – independent estimates of certain gases, – better coverage (not limited to terminator) and – ability to probe thru dust  Both can look down but with loss of sensitivity

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 19 Dust Lifting

What is the vertical distribution of dust during local/regional/global dust events? What are the causes behind the initiation, growth and decay of global dust events? Why do some storms remain small and some grow to global scale?

SOLUTION  Probe near surface environment to determine how dust varies as functions of – winds and turbulence to determine conditions when it is lifted – relative humidity and ice to determine role of condensation in removing dust  TIDS profiles dust and ice via thermal emission with 2 km vert. res.  Co-pointed sat-sat occultations precisely profile down to surface – winds, wind shear, turbulence, – temperature, stability – water vapor – ~100 m vertical resolution to resolve boundary layer evolution over the diurnal cycle with global coverage – independent of dust, – Global perspective on dynamics including baroclinic and tidal modes to determine which events lead to growth of storm – Use measured vertical near-surface diurnal variations to infer exchange of water vapor and energy

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 20 MACO Dust Measurements

 MACO will both observe and see thru the dust  Profile dust opacity with – coincident winds, turbulence, and dynamics context including baroclinic and tidal modes  MIDS will measure emission to profile dust and ice amounts to the surface  Near-IR and visible Solar occultations will profile aerosol opacity and constrain particle size

 Coverage: –Global, diurnal, surface to middle atmosphere

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 21 Single Alt. Horiz. & Moisture Variable Profile Range Vert. WWaatteerr rreemmoottee sseennssiinngg Resolution Accuracy (km) (km/m) How does water vapor vary on diurnal, seasonal & annual Concentration 1- 0- 160 / cycles & what factors contribute? 3% 50 70–200 Mixing ratio 1- 0- 160 / What is the vertical distribution of water in the 3% 50 70–200 atmosphere, both as vapor and ice? Rel. humidity 4- 0- 160 / 6% 50 70–200 r HDO/H O ratio 1- 0- 160 / dq dt = "# • ur q + source + source 2 external int ernal 3% 20 70–2000 Temperature < 0- 160 / MACO sat-sat occs unique feature combination 0.5 K 50 70–200 Pressure 0.1% 0- 160 /  Vertical resolution (~100 m), 50 70–200 !  High precision H2O: 1-3%, T: 0.4K, Psurf: 0.1%  Wind profiling (<3m/s) Insensitive to aerosols

 Unambiguous retrievals for profiling water vapor 80 80 Cold, dry Mars Warm, wet Mars Table D.1-3: Vertical density scales of H2O and 70 70 vertical resolution for state-of-the-art instruments: unresolved, partially resolved, resolved . 60 H O Instrument/ 60 Meteorological 2 Scale vertical resolution Process/Condition Height MCS IR MMLS 50 50 )

s ) m m -km k

5 km 2 km <0.2 km ( k

(

e e d 40 40 d

Well mixed 12 aaa aaa aaaa u t i u t t l i t l

atmosphere A A Saturation in rapidly 1 - 2.5 aaa aaa aaaa 30 30 rising air 20 Saturation in surface 0.4-0.8 aaa aaa aaaa 20 thermal inversions 10 Cold, dry Mars Warm, dry air 0.05 - aaa aaa aaaa 10 overlying cooler, 0.15 Warm, wet Mars moister boundary 0 0 layer 0.01 0.1 1 10 100 1000 1 10 Nov 4, 2009 Decadal Survey Mars Panel - CalteWcather vapor mixing ratio (ppm) Kursinski, et al. 22 Water vapor error (%)

Water Reservoirs

Is the water cycle a “closed” system or is there net transfer of water between hemispheres? What role does subsurface play & what is the surface vapor flux on these timescales?

 Fisher (2007) noted isotopic signatures of multiple water reservoirs exchanging with the atmosphere  Different isotopic compositions indicates the water in each reservoir has a different age  Use isotopic signature of water leaving surface to ID each reservoir and quantify reservoir properties before sending landers  Measuring the isotopic signature of water leaving and later entering each reservoir over the annual cycle to determine whether there is presently a net flow between reservoirs

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 23 More on MACO

Two ~identical satellites carrying different instruments and fuel amounts Satellites stacked on same LV but fly separately to Mars Each carries sufficient fuel to move into final orbit Cost of larger launch vehicle < cost of aerobraking 2 satellites All instruments are co-aligned, have no pointing capability of their own (S/C does all pointing) and no moving parts Lower satellite – carries sat-sat occ receiver – does solar occultations Upper satellite carries – Sat-sat occ transmitter – Thermal IR aerosol profiler  Detectors would vaporize looking at sun – Looks at surface under occultation profile to measure surface temperature and frost (if present) Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 24 MACO Foreign Contributions

Near-IR spectrometer for trace gas survey provided by foreign partner, either ACE (Canada) or SOIR (France) Frawst instrument simple near-IR spectrometer to measure surface frost under each occultation (French/Russian contribution) Two channel visible solar occultation instrument, LIMO, contributed by Canada to constrain aerosol size properties. Meteorological context imager assumed to already be available in orbit

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 25 MACO Operations

 Highly automated operations analogous to GPS occultations because observation schedule is tied to orbital geometry (which is known before launch)  DSN communications – Deep space antenna is not gimbaled – Every 2-3 days, spacecraft briefly stop science acquisition and burst downlink data to Earth – Use DSN tracking for precise orbit determination – Calculate next observation schedule and uplink to the two spacecraft during next DSN tracking interval

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 26 ContributionsContributions toto MarsMars InfrastructureInfrastructure

Function Contribution

Telecom Redundant telecom relay & doubled bandwidth Global Aerobraking; near-surface weather winds & turbulence for EDL & system design

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 27 MACO/DSM Cost

2006 2011 RY RY Phase A 2 3 2006 RY: actual MACO #s Proj mgmt/Mission 23 32 analysis/Sys engr Nav & design 6 8 2011 RY: is 2006 RY Instruments 47 65 increased by 20% Spacecraft Bus and I&T 155 214 + 5 yrs of inflation Science Team 8 11 EPO 1 1 GDS dev 20 28 DSN 2 3 Phase A-D reserves 69 95 sub total 333 460 Phase E cruise+1 Mars year 44 61 Phase E reserves 4 6 Launch 148 204 Nov 4, 2009 Total Dec5a2d9al Surv7e3y 0Mars Panel - Caltech Kursinski, et al. 28 Other Sat-Sat Occultation Implementation Options

 Ride on international partner  One large, one quite small carried by  2 with full pointing on large spacecraft

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 29 International Partnering Possibilities

 On 2016 orbiter, carry mm-receiver capable of TE, SO and sat-sat occ.  Carry the mm-transmitter on international partner satellite – Candidates: Japan, India, China  10/27/09 met with Takehiko Satoh, head of Japanese MELOS science team and discussed possibility of flying occultation transmitter on 2018 MELOS orbiter. – Japanese are interested – MELOS can provide precise pointing and USO for occ. transmitter – Proposed MELOS orbit is highly elliptical, slow precession rate very different from high inclination LMO – Coverage needs to be determined – will NOT provide the even global and diurnal coverage of 2 dedicated S/C like MACO Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 30 MicrosatMicrosat FFreeree FlyerFlyer OptionOption

Large satellite could carry microsatellite dedicated to the sat-sat. occ transmitter then release µsat once in orbit - Orbital inclination of µsat will be same as that of large satellite - For optimum coverage, precession rate must equal that of large satellite => Same orbit as large satellite Repeating pattern on surface - at (integer multiple of) 21 locations - Twice per day sampling like balloon network on Earth Sequence to get to final orbit (same approach used to deploy COSMIC GPSRO constellation) µsat orbit altitude would differ causing orbit to precess relative to large satellite. Then after several months when ascending node is approximately ~180o, different that large satellite, raise or lower altitude of µsat orbit to match orbit of large satellite (but 180o out of phase). Now have two counter-rotating satellites in same orbit

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 31 FFrreeee FFllyyeerr CCoosstt

- Large satellite has to carry fuel needed to slow down the extra mass of the µsat - Micro-orbiter purely for science to minimize cost - Allocate ~6 months to precess into position - Attitude control via star trackers - Solar panels for power - Instrument requires ~120 W when xmt, 10 W orbital average - Instrument mass: 10-15 kg? - UHF comm. - POD derived from UHF and mm-wave crosslink - Need to fully cost this

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 32 Mars mm-wave instrument Simple, heterodyne system spanning 320-360 GHz, no cryogenics ~ 20 cm aperture for 2 satellites in LMO like MACO – Requires ~ 1 mrad of pointing control (=> star trackers on s/c or instrument) 3 modes: 1. Thermal emission (receive spectrometers) 2. Solar occultation (receive spectrometers) 3. Satellite-satellite occultations (active ~ 8 tone spectrometer) – 3 modes share share receive antenna and receiver front end – Split downconverted signal into  passive FTS (TE & SO)  (4 to) 8 coherent narrowband receiver channels – Sat-sat requires 2nd satellite carrying transmitter Calibration – Occultations are self calibrating, eliminating long term drift  View occultation source immediately before or after each occultation – Calibrate thermal emission (TE) against sat-sat occultations  Instrument designed to do both sat-sat occ. & TE observations simultaneously  Calibrate entire retrieval (rather than just the TE observations)  Eliminates need for hot calibration source Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 33 Mm-wave Instrument Heritage

 All needed parts have flown in space  Need to develop complete instrument  Prototype 2 channel 183-203 GHz instrument now running

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 34 Earth Demonstration: ATOMMS

 NSF funded ATOMMS MRI based on its promise as a model-independent climate sensor with higher accuracy, precision, vertical resolution and works in clouds  NASA providing aircraft time  Probes – 22 & 183 GHz water vapor lines – 184 & 195 GHz ozone

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 35 AATTOOMMMMSS DDiiffffeerreennttiiaall AAbbssoorrppttiioonn

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 36 Precision of Individual ATOMMS Profiles

water vapor temperature 90km

8 0 8 0 1% 10%

183.31/179.0 6 0 6 0 ) ) m m k ( k (

e e d d u t u i t i t l t l

A 4 0 a 4 0 lo-band: 8.0, 13.0, 17.5, 20.0, 22.21, 32.0 + hi-band: 179.0, 182.2, 183.0, 183.2, 183.3, 183.31 183.30/179.0 S N R (183GHz) = 1800 + high altitude pressure boundary condition v0

ionosphere max day (abs) lo-band: 8.0, 13.0, 17.5, 20.0, 22.21, 32.0 0.005 mm/s RMS velocity error + hi-band: 179.0, 182.2, 183.0, 183.2, 183.3, 183.31 without the high altitude pressure boundary condition local multipath 2 0 2 0 abel integral initialization lo-band only: 8.0, 13.0, 17.5, 20.0, 22.21, 32.0 hydrostatic integral initialization Horizontal + tropical water vapor error Water vapor error for 35S (June) With turbulence Water vapor error for 60S (June) no hydrostatic initialization

0 0 0km 0.01 0.1 1 1 0 0.01 0.1 RMS temperature error (K) Nov1% 4, 2009 Fractional RMS water vapor error 10%Decadal Survey Mars Panel - Caltech0.1K 1KKursinski, et al. 37 Aircraft-Aircraft Demonstration  In 2010, occultation between 2 WB-57F aircraft flying near 19 km altitude  Perform series of rising occultations  Measure phase and amplitude at several wavelengths  POD: GPS + accelerometers  Pointing via WAVES gymbal

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 38

Recent ATOMMS Testing

 Recently completed initial prototype 180-204 GHz transmitter & receiver  Initial water vapor measurements over an elevated ~1 km path length on UA campus

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 39 First Set of 183 GHz 1 km Occultation Measurements

Initial set of 1 km differential absorption measurements made 10/30/09  Compared against rooftop capacitive relative humidity sensor, – had to be re-calibrated against sling psychrometer  Preliminary agreement to ~2%(!) – Still refining calibration and spectroscopy

Initial turbulence-scintillation measurement  No clear detection of scintillations in first two nighttime measurements – 1 km path is short particularly in non-summer – Turbulence weak at night  Will measure in daytime  Looking to increase path length

Nov 4, 2009 Decadal Survey Mars Panel - Caltech Kursinski, et al. 40