DESIGN AND DEMONSTRATION OF THE MARS ORGANIC MOLECULE ANALYZER

(MOMA) ON THE EXOMARS 2018 ROVERXiang Li4 , Ricardo Arevalo Jr.1, Will Brinckerhoff1,

Paul Mahaffy1, Friso van Amerom2; Ryan Danell3; Veronica Pinnick4,, Lars Hovmand5, Stephanie

Getty1; Fred Goesmann6; Harald Steininger6; and, the MOMA Team1-6

1NASA GSFC, Greenbelt, MD; 2Mini-Mass Consulting, Inc., Hyattsville, MD; 3Danell Consulting, Inc., Winterville, NC; 4University

of Maryland, Baltimore County, Greenbelt, MD; 5Linear Labs LLC, Washington, DC; 6MPS, Lindau, Germany

Planetary Exploration: An Historical Perspective• Since the Pioneer Venus Program (1970’s), quadrupole

mass spectrometers (QMS) have served as our primary means to explore the inner and outer reaches of the solar system

2

Pioneer Venus ONMS Galileo Probe MSCassini INMSHuygens GCMS

LADEE NMSMAVEN NGIMSMSL SAM

Mars Phoenix TEGA

Giotto IMSDelivered by and/or in collaboration with NASA GSFC

Mass Spectrometers

3

An analytical chemistry technique that helps identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions.

• Compound Introduction

Gas chromatography(GC), Liquid chromatography(LC)……

• Ion Source

Electron ionization (EI), Laser desorption(LD), Inductively coupled plasma, Chemical ionization (CI)……

• Mass analyzer• Data collection Spiraltron, Microchannel plate, Faraday

cups……

• Data analysis

Mass Analyzer

• Sector Instrument

• Time-of-Flight

• Quadrupole mass filter

4

Along came the ion trap…• Ion trap mass analyzers offer advanced

analytical capabilities, plus mechanical packaging benefits, for spaceflight applications and planetary exploration, including (but not limited to):

5

Modified from Stafford (2002)• Ion storage & mass filtering• Compactness (small footprint)• Structural information (MSn)• Selective ion isolation/enrichment • Operation at elevated pressures io

nsou

rce.

com

• BONUS: Ion traps have already been qualified in space– MARINE trap measured ppb-level gases for air quality on the ISS (VCAM)– Ptolemy on the Philae lander set to characterize comet 67P/C-G composition

Mars Exploration in This Decade

• Future Planni

ng

MOMA Investigation Science Goals1. Detect and characterize organic molecular structures

• Measure and identify/disambiguate potential organic signatures

2. Analyze a range of volatile and nonvolatile compounds• Search for low-mass organics/evolved gases and high mass more refractory phases

3. Derive the inorganic geochemical context of organics • Provide supporting measurements of mineralogical and bulk chemical composition

Mode of Operation Pyr/GCMS LDMS

Flight HeritageLinked to Viking, Phoenix, and SAM/MSL science NEW!!

Targeted Analytes(semi-)volatile organics & thermally evolved gases

nonvolatile organics & inorganic species

Mass Range 50 – 500 Daltons 50 – 1000+ Daltons

Sampling Processing & Ionization Source

ramp heating rock powder & ionization by e- beam

Direct laser desorption/ ionization of crushed rock10 100 1000

0

20

40

60

80

100

120

140

160

Molecular Weight (Da)

Enth

alpy

of V

apor

izati

on D

Hv

(kJ m

ol-1

)

Lase

r Des

orpt

ion

kerogen

macromolecular carbon

atmosphere

Pyr

olys

isDer

ivat

izat

ion

MOMA Mode Optimal Range

50

7

The Next Spaceflight Ion Trap: MOMAMission: ExoMars 2016/2018Destination: Mars orbit/surfaceRover Launch: May, 2018Rover Landing: Feb., 20192018 Duration: 218 sols surface ops

ExoMars Program Objective:• Establish if life ever existed on Mars

ExoMars 2018 Rover Science Goals:1. Search for signs of past and

present life in the Mars (sub)surface

2. Investigate the water/geochemical environment versus depth (notional concept)

“Mother MOMA” Hardware Contributions

8

GC MEB LPU RFWRP

Laser

MSSEB

Tapping

Ovens

ESA’s ExoMars rover will carry onboard the next space-borne ITMS: MOMA

The MOMA-MS Engineering Test Unit (ETU)

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ETU Linear Ion Trap

266 nmpulsedUV laser

Wide-rangeturbo pump

Multipin &HV headers

MS housing

RF supply

µPiraniheader

EI Source

Rods

GC InletHV Shield

The MOMA-MS Engineering Test Unit (ETU)

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WRPHousing

Micropirani gauge

(bottom-side)Aperture Valve

316L DET shield(HV field control)

316L High-voltagefield bushing

Channel ElectronMultiplier (CEM)

Ion trap endplate(TiN coated)

Dual e-gun EI source

Dynode HVfeedthrough

Alumina mount/electrical isolator

Flight Model (FM) of the MOMA MS Ion Trap

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MOMA-MSSource

*Identical Dual E-Guns**Modified Ion Optics*

HERITAGE DESIGN

SAMSource

1 cm 1 cm

Redundantelectron gun

assemblies

Key Technology: Electron Ionization Source

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• Heritage-derived closed source, modified from the Sample Analysis at Mars (SAM) design (operating on Mars now…)

• Fully redundant electron guns employ 0.003” diameter W:Re filaments, producing 10 – 100 µA emission

Valve “open”Valve in“closed” position

Ion guide

Check ball

Pull-type solenoid

Hall sensorThermal sink

Ball “seat”

Magnetic windings

Recoil spring Sample sideion guide

Key Technology: Aperture Valve

13

• Fast actuating (<50 ms open/close) check-ball aperture valve delivers robust performance during LDMS particulate generation

Leak Rate:<1E-6 cc/sec He(at atmosphere)

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Key Technology: Electron Multiplier Detectors

Ion opticalaperture

Discretedynode

Shield

Pulse-countingcoax connector anode

Conical cathode(-1.8 kV to -3.0 kV)

HV bushing

1 cm

Spira

ltron

(6 c

hann

el)

Prea

mpl

ifier

Custom Photonis Spiraltron 4219 CEM

Ground connection

Faraday Cage Shield*Field control bushing

Low-VoltageBaseplate

AluminaMount

Contact Sleeve*Electrical continuity CEM Detector Weld Flange (Flight Model)

Why a 2D Ion Trap versus a 3D?• An ion trap was required for the MOMA Investigation in order

to enable LDMS at Mars ambient pressures (4 – 8 Torr, primarily CO2)

• Compared to a 3D trap with a similar physical volume, a 2D linear ion trap (LIT) offers the following advantages:– Increased ion storage volume, and by extension reduced space-charge

effects – Symmetrical ion injection pathways, supporting multiple ion sources– Higher trapping efficiency (increased sensitivity)– Redundant detection subassemblies– Link to heritage QMS design/assembly (in the case of MOMA)

• Hyperbolic rod design, alignment tolerances, electrical connections, etc.

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SAM QMS (6” rods)

Cassini INMS (4”)Huygens GCMSLADEE NMSMAVEN INMS

MOMA(1” rods)

2.8

cm

MOMA LIT rod assembly

2.7

cm

MAVEN switching lens

Modes of Operation (and Sequence of Events)

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Linear Ion Trap (LIT)

Effluent from the gas chromatograph

Pyr/GC-MS ion introduction

~10 cm (a very small mass spectrometer!)

Mars sample

Aperture valve (closes off tube

after ions captured)

Ions drawn into capillary ion guide tube

LDMS ion introduction

Detectors

2. Laser Desorption/ Ionization (LDI) source

1. Electron Ionization (EI) source

Prototype GC, Tapping Station and Pyro Oven

coupled to MS breadboard:

1. Interface testing

2. Functional demo

3. Prelim testing of S/W

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Pyr/GCMS: Volatile Organics Detection

CALIBRATION: 5 ppm (w/w) Perfluorotributylamine (PFTBA) in 3 mTorr He

0.46 Da

0.41 Da

0.58 Da

0.46 Da

CF3+

C5F10N+

C9F20N+

C3F5+

MS

SIG

NAL

GC

TCD

Hexane

Benzene

Selected Ion Chromatograms from MSGC + MS CouplingTotal Ion Chromatogram

butane

pentane

hexane

benzene

LDMS: Nonvolatile Organic/Inorganic Detection

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Matrix ion clusters

FWHM1.46 Da

1 pmol/mm2 Angiotensin II7 Torr CO2 Mars Pressure

• Functional/Performance Requirements:– ≤1 pmol/mm2 of analyte (Angiotensin II) with

SNR ≥ 10– ≤2 Da mass resolution across 500 – 1000 Da

mass range[M+H]+

m/z = 1047

LDMS: Nonvolatile Organic/Inorganic Detection

Cs(CsI)n+

n=0

2

3 4

5

6

7

89

10

1

19

m. w. = 151

LDMS: Nonvolatile Organic-Neat

Adenine[A+H]+

[A2+H]+

[A3+H]+

Guanine

[G+H]+

[G2+H]+

[G3+H]+

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LDMS: Nonvolatile Organics in Mars Analogs

Brucite (Mg(OH)2)+ 1%w Adenine

[A+H]+

[A2+H]+

[A3+H]+

Forsterite(Mg2SiO4)+ 1%w Adenine

[A+H]+

[A2+H]+

[A3+H]+

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Rela

tive

Inte

nsity

Rela

tive

Inte

nsity

LDMS: Nonvolatile Organics in Mars Analogs

MgCO3 (reagent)+ 1 wt.% Ca(ClO4)2

+ 10 ppm (w/w) coronene

Coronene (PAH)MW = 300.4 Da

BCR-2 (basalt)+ 1 wt.% Ca(ClO4)2

+ 10 ppm (w/w) coronene

SWy-2 (montmorillonite)+ 1 wt.% Ca(ClO4)2

+ 10 ppm (w/w) coronene

PLUS,

PLUS,

PLUS,

Ca+

Ca+

Ca+

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Magnesite(secondary

mineral)

Basalt(primary

rock)

Smectite clay

100 200 300 400 500 600 700Mass-to-charge ratio (m/z) in Daltons

Rela

tive

Inte

nsity

ASTROBIOLOGY, Volume 15, Number 2,104-110, 2015. DOI: 10.1089/ast.2014.1203

Special Tools: SWIFT Isolation/Enrichment

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Linear Ion Trap (LIT)

Mars sample

Aperture valve (closes off tube

after ions captured)

Ions drawn into capillary ion guide tube

LDMS ion introduction

Laser Desorption/ Ionization (LDI) source

Apply SWIFT waveform

~10 cm (a very small mass spectrometer!)

Special Tools: SWIFT Isolation/Enrichment

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1 laser shotTIC = 1396

NAu-2 (nontronite) + 10 ppm (w/w) coronene

Eject

1 laser shotSWIFT during trapping

TIC = 386

2 laser shotsSWIFT during trapping

TIC = 1457

Special Tools: SWIFT Isolation/Enrichment

Full SpectrumSWIFT spectrum

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SWIFT ion enrichment and MS/MS analysis• MOMA’s SWIFT and MSn capabilities can

be employed for ion enhancement and deriving structural information

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10 pmol/mm2 Angiotensin IIFull Mass Scan

[M+H]+

Isolation of [M+H]+ at 1047 Da via SWIFT [M+H]+

y7

SNR = 40

b7+H2O

b6b6-NH3

b5y3 b4b3-NH3

Fragmentation of [M+H]+

Summary/Conclusions• Ion traps have only begun to be exploited for spaceflight

applications• MOMA (via ExoMars 2018) is charged with searching for extinct

and/or extant life on Mars through the chemical characterization of near-surface samples (from ≤2 meters depth)– Pyr/GCMS to measure (semi-)volatile organics and evolved gases

• Direct link to Huygens/Phoenix/MSL science, operations and data products

– LDMS at Mars ambient pressures to detect nonvolatile organics and inorganic mineralogical signatures • Innovative technique for searching for organics even in the presence of

perchlorate

– SWIFT and MSn capabilities enable enhanced performance and structural information to be derived from samples analyzed in situ

• The MOMA instrument architecture is already being leveraged:– LITMS (GSFC): Anion detection, high-T pyrolysis and LDMS mapping– AROMA (GSFC): High mass resolution for molecular disambiguation

2706 March 2015 It’s a Trap! (R. Arevalo Jr.)

Questions? Comments?

Contact InformationXiang LiXiang.li@NASA.GOV

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