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PRINCIPALS OF VOLATILE COMPONENTS MEASUREMENTS IN THE GAP EXPERIMENT ONBORD THE PHOBOS-GRUNT MISSION AND BEYOND.
M.V.Gerasimov and the GAP team
IKI RAS, Moscow, 11.10.2011
Kaidun
Phobos
Origin of Phobos?
Trapped asteroid or in orbit formation?
How much it was differentiated?
Which type of meteorites simulates its material?
What can we learn from investigation of volatiles of Phobos?
Concentration of volatiles in different petrographic types of meteorites (Wood, 1968)
petrographic types 1 2 3 4 5 6
Sulfides - >0.5% <0.5%
Carbon ~ 2.8% 0.6 – 2.8% 0.2 – 1.0% <0.2%
Water ~20% 4 – 18% <2%
Carbonaceous chondrites
Moon
Earth
SNC meteorites(Mars)
Ordinary chondritesPrimitive water
δ1
7 O, ‰
δ18O, ‰0 5 10 15
-6
-4
-2
0
6
4
2
8CI
CO
CV
CRCH
CM
Oxygen isotopes in the Solar System
- to investigate the origin of Martian satellites on example of Phobos;
- to investigate properties of small planetary objects in space environment;
- to study possible differentiation of early planetary materials;
- to study volatiles inventory;
- to study organic materials;
- to study the influence of Phobos on the near Martian environment (dust torus, gas, plasma and magnetic field perturbations);
- to investigate the detailed structure of the Martian atmosphere including vertical profiles of temperature, aerosol, and trace atmospheric components (water vapor, CO, CH
4, etc);
- to investigate diurnal variations of surface temperature of Mars.
Scientific objectives of the “PhSR” mission
Phobos Sample Return mission (2011)
Three main questions to characterize volatiles:
1. Concentration of volatile elements?
Concentration = Total mass of the volatile element in the sample
Mass of the sample
water
organics
trapped hydrogen
other
hydrogen
Three main questions to characterize volatiles:
1. Concentration of volatile elements?
2. Form of incorporation of volatiles in the soil?
carbonates
carbides
organics
other
carbon
3. Isotopic composition of volatile elements?
Three main questions to characterize volatiles:
1. Concentration of volatile elements?
2. Form of incorporation of volatiles in the soil?
Gas Analytic Package (GAP) for the “Phobos Sample Return Mission”
Scientific objectives of the GAP1. Investigation of chemical composition and inventory
of volatiles (water, СО2, N2, SO2, organics, noble gases, etc.) in situ in the soil at the landing place;
2. Investigation of volatile-containing phases in the soil of the Phobos;
3. Investigation of organic components in the soil of the Phobos;
4. Measurement of isotopic composition of CHON elements (13С/12С, D/H, 17O/16O, 18O/16O, 15N/14N) and noble gases;
5. To constrain the mineralogical composition of the Pobos soil (with emphasis on the volatile-bearing minerals) on the basis of thermal and gas evolving experiments with the use of data from other experiments.
The structure of the GAP
Soil preparationand loading
system
ThermalDifferentialAnalyzer
ChromatographMass-
spectrometer
TDA
MS
GC
Objectives of the TDA
1. To measure exo- and endothermal reactions in the sample of soil to determine minerals with phase transitions at temperatures <1000C;
Thermal Differential Analyzer (TDA)
2. To perform the release of volatile components into the gas phase and provide their transfer into GC and MS;
3. To perform pyrolysis of heavy organics (kerogens?) for their analysis in GC and MS;
SOil Preparation SYStem = SOPSYS
Tasks of the device
1. To take a portion of soil from the manipulator.
2. To mill large pieces of rocks and sieve the soil to extract the necessary fraction for loading into pyrolytic cells.
3. To extract the dose of the sample for loading into the pyrolytic cell.
4. To clean itself for the next cycle.
Pyrolytic cell
Cell parameters:
Т mах - 1000С (1350С) W max - 22 WMass - 20 g
He He + газы
10
9
1
2
3
4
7
6
8
11
5
Sample volume - 4 mm 5 mm
PC cross-section
Tasks of the chromatograph
1. Accumulation of gases which are released from the sample during pyrolysis.
2. Redistribution of gases of different types (permanent gases, organics, etc.) between respective columns.
3. Separation of different gases by time of retention.
4. Measurement of abundance of separate gas component.
5. Measurement of isotopic ratios of D/H, 13C/12C, 17O/16O, 18O/16O in CO2 and H2O using TDLAS.
Gas Chromatograph
HDOH2
17OH2
18O
H216O
HDO
H216O
H216O
Laser = 2.64 m
Name* Target molecule
Sigma (cm-1) Lambda (nm)
C2H2 C2H2 6523.8794 cm-1 1533 nm
CO2iso 18OC16O 4898.7822 cm-1 2041 nm
18OC16O 4899.5653 cm-1
13CO2 4899.6133 cm-1
H2Oiso HDO 3788.3366 cm-1 2640 nm
H2 17O 3788.7852 cm-1
H2 18O 3788.9125 cm-1
H2O-CO2 H2O 3727.7376 cm-1 2682 nm
CO2 3728.4101 cm-1
TDLAS scheme
Assemblage of the GC block
Carrier gas tanks (Не) 2250 см3 40 bar.
Pressure sensor
Calibration gas tankPressure regulators
TDLAS tube Injection traps
GC modules
ON/OFF valvesmanifolds
6 2006 1956 1906 1856 1806 1756 1706 1656 1606 1556 1506 1456 1406 135
415 000
410 000
405 000
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395 000
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385 000
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365 000
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345 000
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315 000
310 000
305 000
300 000
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290 000
415 000
410 000
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hexaneС6Н14
4,410-8 g benzeneС6Н6
4,010-8 g
A piece of test chromatogram
signal/noise ~ 600
The mass-spectrometerL.P. Moskaleva (PI) Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI)Ryazan University (contractor)
Block of electronics (BE)
Mass analyzer (MA)
Main parameters of the MS
1. Mass - 3,5 кг2. Power consumption - 32 Вт3. Dimentions: МА - 256х78х73 (mm)
BE - 256х110х120 (mm)4. Mass range - (2÷400) amu/q5. Sensitivity for Ar - (3÷5)х10-12 hPa6. Dynamic range - 104
7. Mass resolution - 400(?)
A test mass-spectrum of CO2 in GC+MS mode
Mass number (amu/q)0 10 20 30 40 50 60 70 80 90 100
Sig
nal (
a.u.
)
0
200
400
600
800
1000
1200
ÑÎ 2+
m/z=44
ÑÎ +
m/z=28
H2Î+
m/z=18
Î 2+
m/z=32
Î +
m/z=16
C+
m/z=12 He+
m/z=4
- background spectrum
Main partners of the Phobos-GruntGas Analytic Package team
IKI RAS (Russia) TDA+GCGEOKHI RAS (Russia) MS
LATMOS (France) GCLISA University of Paris (France) GCGSMA (France) TDLAS
MPS (Germany) GC
Polytechnic University of Hong Kong (China) SOPSYS (TDA)