TIMM: ECHELLE-SPECTROMETER TO STUDY THE ATMOSPHERE OF MARS
O. Korablev1, F. Montmessin2, A. Trokhimovsky1, A.A. Fedorova1, A.V. Kiselev1, J.L. Bertaux2, J.P. Goutail2, D.A. Belyaev1, A.V. Stepanov3,1, A.Yu. Titov4, Yu.K. Kalinnikov5, O.N. Andreev1, O.E. Kozlov1, A. Venkstern1.1 Space research Institute (IKI), Moscow2 LATMOS, Guyancourt, France3 Physical faculty, Moscow State University4 Special Design Office of IKI, Tarusa, Kaluga reg.5 VNIIFTRI, Mendeleevo, Moscow reg.
• Krasnopolsky et al. 2004• CFHT (3.6 m @ 4.2 km alt) FTS, resolution
0.017 cm-1 (ν/δν = 180,000) • 15 linesCH4 at 3.3 µm• Methane detected at 10 ± 3 ppb
• PFS/MEX : resolution 1.2 cm-1 • Mean 10.5 ppb, variations 0-30 ppb
Methane on Mars: detection from the Earth and PFS/Mars Express
Astronomical mapping of methane
Gemini-South, Keck-II telescopesEchelle-spectrometersMumma et al. 2009
Methane detected ? Questions arising…
• Biogenic/Abiotic sources– Rarified biota– Gas hydrate deposits– The 13С/12С ration in methane
• Methane is photochemically stable (lifetime ~300 y). What could explain its variability?
• Sinks of methane?– Atmospheric electricity?– Resulting products formaldehyde?
New measurements from the orbit and on the surface of mars are needed
Recent measurements: EPSC-DPS in Nantes
• Krasnopolsky (EPSC-DPS in Nantes from abstract): CSHELL/IRTF February 2006: methane below 10 ppb
• Villanueva et al (EPSC-DPS in Nantes): CRIRES/VLT, NIRSPEC/Keck-2, CSHELL/IRTF 2009-2010: low upper limits for methane
• PFS: Geminale et al. PSS 2011
Trace gases in the atmosphere and new missions
• Mars Science Laboratory (2011) rover– TDLAS in SAM (Webster&McHaffy PSS 2011)– Concentration and isotope measurements
• ExoMars (ESA) Trace Gas Orbiter (2016)– MATMOS (JPL, Fourier occultation
spectrometer)– NOMAD (Belgium +, Echelle spectrometer
occultation + nadir)
• Phobos-Grunt:– AOST: Fourier-spectrometer : 0.9 cm-1 in
occultation – TIMM: Echelle spectrometer 0.1 cm-1 in
occultation
TIMM-2 = ТИММ• Echelle-AOTF instrument (similar to SOIR/VEX)• Main goal : methane detection and profiling in solar
occultation• Added to the payload after the shift of launch to
2011• Occupies the resources of Italian TIMM (thermal IR
mapping of Phobos; was not delivered) • Delivered to Lavochkin Assoc in July 2011 and put on
the s/c• Officially included in the payload: Aug 2011• successful tests onboard: Sept 2011
Science goals• Sensitive measurements of minor species (high signal/noise, high resolving power
Δν~0.1 cm-1)
• CH4 (detection threshold <0.5 ppb, 20 times below present)
• HDO/H2O• Aerosol profiling
• Other minor species• CO2 isotopes
For methane: first CH4 measurements from the orbit around Mars after PFS:– Confirm detection– Confirm variability ?-limited mission time
For HDO:– First simultaneous measurements of HDO/H2O D/H (known from groundbased astronomy,
HDO and H2O measured separately)– Vertical profiles
For aerosol: vertical profiling of optical properties in broad spectral range– determine size distributions– Together with AOST: determine the ratio of visible/thermal infrared opacity
Mission scenarioLaunch 8.11.2011 By Zenith from Baikonur Best date 11.11
Cruise 11.09.2012
3-day orbit 21.09.2012 800x75 900 km; 1.8° Release of YH-1
3-day orbit bis 30.09.2012 780x74 800 km; 1.5° Pericenter ascent
Intermediate orbit (3.5 d) 8.10.2012 6500x73 452 km; 1.1° Circularization
Observation orbit 14.01.2013 H=6470; T=8.27h; 1.1° 3 months; observation of Mars
Quasi-synchronous orb. 14.02.2013 5850x6100 km; T=7.65h 1 month; observation of Phobos
Landing 14.02.2013
Return cruise ~11 months
In the vicinity of Mars: Ls=170–264°. Global Dust Storm ?
TIMM heritage
Echelle+AOTF combination
SOIR/Venus Express Made in Belgium
RUSALKA/ISS Made in IKI
Optical layout of the compact echelle-AOTF spectrometer
TIMM-2 design drivers
Empty place for TIMM-2
Trying on the STM (1.02.2011)
• Provide sufficient spectral resolution resolve methane and HDO/H2O features
• Extremely limited development time (and budget)• Very limited space onboard (2010 passed essentially
in negotiating the mechanical envelope)• Resulting largest dimension 260 mm
+XSun direction
TIMM LOS
spectral coverage• Standard echelle grating (Newport/RGL):
– loose spectral coverage+ No influence of AOTF sidelobes+ Most of minor species of interest covered
TIMM orders• Could not combine Q-branch of CH4
and isolated HDO features• P4 line of methane (23 order)• No possibility for HCl, C2H6 etc
• CO2, H2O, CO well covered
Parameter High-resolution channel Photometric channels
Spectral range 2400 – 4200 nm 250 - 1500 nm
Resolving power, (/∆) > 20 000 30 - 150
Working spectral intervals 14 ranges ∆ = 14 – 23.5 nm 250, 340, 990, 1550 nm∆ = 10 nm
FOV 1.5×21 arc min Ø3.5 arc min
Spatial resolution at limb from Phobos orbit
60×2 km 10 km
AOTFTeO2, 20 - 40 MHz,
bandpass 20±0.5 cm-1,effectiveness 40% at 3390 nm
-
Echelle gratingNewport/RGL
24.355 gr/mm, Blaze angle 70°, Working area 46×96 mm
-
DetectorSOFRADIR
320×256 pixels 30×30 µm.Ricor-Thales Stierling cooler
Hamamatsu3 Si photodiodes 2x2 mm
1 InGaAs photodiode Ø1 mm
Power consumption Stand by 2 W.Operation12 W ave.
Memory RAM 8 Kbytes FIFO 256 KbytesFlash 256 Mbytes
Data rate Max 40 kb/s ; 22 Mb/session
Mass 2830 g
Dimensions 262×165×139 mm
folded optical scheme
main optical componentsmain optical componentsTelescope (Cassegrain, Al mirrors)
AOTF
HgCdTe 320x256 SOFRADIR MARS
MW detector (LATMOS)
Spectrometer
AOTF
f = A*+ B A B
AOTF1 0.009413481382539 -2.478479546760679
AOTF2 0.009406684896203 -2.458095239317771
Spectrometer
3.39 HeNe laser:λ/Δλ≈25000
Photometric channels
#q Target λ [nm] Δλ [nm]
Aperture, Ø [mm]
Diaphragm Ø [µm] Detector
6 Ozone 250 10 11 100 Si 2.4x2.4 mm Hamamatsu S1336-5BQ
8 Aerosol, ozone 340 10 8 100 -'-
5 Aerosol 990 10 3 100 -'-
7 Aerosol 1550 12 3 100 InGaAs Ø 1 mmHamamatsu G8370-01
1-4 Pointing monitoring 550 1 3 - Si 4x 1x1mm
ФД19КК
Flight unit
Electronic block diagramSIOK (S/C),
GCE
Controller MIL1553
TIMM
Service port
Controller
FPGA
AOTF
ADC
Photometers pointing sensor
SOFRADIRADC
FIFO
Flash
Ricor cooler
FPGA registers GCE
4/07/2011
Back-up
IR-spectroscopy
Spectral range 2,5 – 25 μResolution: 0.9 cm-1
Field of view - 2.3 deg Mass 4 kg
PI: O. Korablev, IKI
Fourier SpectrometerAOST
Martian atmosphere– Methane, minor constituents (by Sun
occultations)– Profiles of temperature; diurnal variations– Monitoring of aerosols
Martian soil– Discriminating chemically-bound and
adsorbed water bands– Diurnal variations (temperature profiles,
surface frosts)
Phobos– Global mineralogical mapping (from quasi-
synchronous orbit)– Site spectrospy at cm-scale (after landing)
Main parameters of AOSTMode Solar occultation Atmosphere Surface
Spectral range, µm 2.5÷20 6÷25 2.5÷25
FOV 2.5°
Etendue m2sr 4.4 10∙ -7
Footprint Full solar disk0.35°
At Mars(in nadir from OO)
290 km
At Phobos(in nadir from QSO)
2.2 km
Optical Path Difference, cm 1.1 0.55 0.14
Spectral resolution, cm-1 0.9 2 7
Duration of observation s 5 50 50
Signal/Noise 100÷500 10÷500 10÷500
Interferogram lengths (number of points) 16384 8192 2048
Data rate, kb/spectrum 18 9 2.2
Mass, kg 4.1
Power consumption, WLess than stand-by
operation3
10
AOST: signal-to-noise and calibration spectra
Estimation of S/N
Laboratory BB spectrum (T=950°C; 5 s measurement)
Occultation of sun by AOST
• CH4
• D/H
• aerosols