The Mars Microphone onboard Supercam for the Mars 2020 rover
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The Mars Microphone
onboard Supercam for the
Mars 2020 rover
David M im oun 1 , Sylvestre Maurice 2 , Anthony Sournac 1 , Alexandre
Cadu 1 , Marti Bassas 1 , Murdoch Naomi 1 , Baptiste Chide 1 , Jérémie
Lasue 2 , Ralph Lorenz 4 , Roger W iens 3 and the SuperCam team
(1) Université de Toulouse, ISAE-Supaero, DEOS/SSPA, Toulouse,
France (david.mimoun@isae.fr),
(2) IRAP, CNRS, Université Paul Sabatier, Toulouse, France,
(3) LANL, Los Alamos, NM
(4) APL 1
A Short History of Planetary
Microphones (1/3)
n The short history of the planetary
microphones began probably with Grozo
2 instrument during the Venera 13 and 14
mission
(http://mentallandscape.com/V_Venera11.htm)
n First Planetary microphone on Huygens
n Successfully retrieved the descent sounds
n
2 June 2011 - 2
A Short History of Planetary
Microphones (2/3)
n Second opportunity on Mars Polar
Lander
n Mars Microphone Development up to FM
by Greg Delory (UC Berkeley)
n Support by the Planetary Society
n Failed landing of MPL
n Third opportunity with Phoenix : sound
coupled with Mardi imager (Not used)
3 June 2011 - 3
A Short
Taking into account both the History
sensor and of
the Planetary
lander requirements, two possible a
are studied and shown inMicrophones (3/3)20. For exact dimensions, det
the Figure 19 and Figure
additional views, please refer to Annex #4. Schiaparelli, w/o heat shield & back cove
MicroAres
MarsWind
MarsTem
Camera FoV
55°x83°
Camera
System MicroMED
MEtBaro
The Mars Microphone sensor was
Microphone
CEU Sensor Elect.
considered a low-risk development, but was
judged by the Science panel to lack
Lande r sufficient scientific justification
Battery
MicroMIMA
Camera
Cal. VISTA
Traget
MicroMETSIS
Microphone
Sensor
Figure 19: DREAMS accommodation #1, CEU and Battery in place of CTPU position.
MarsTem
MarsWind 4
Acoustics on Mars is complicated
Very strong absorption
Williams (2001)
Sound amplitude as a function of the distance for noise source = 60 dB
60
4m
7m
10 m
50
40
Sound intensity (dB)
Increasing distance
Sound amplitude vs. 30
distance on Mars
20
10
0
102 103 104 105
Frequency (Hz)
5
Microphone science goals have
to be crystal clear
6
SuperCam on Mars 2020
Dr. Steven J. Rehse / W hat is LIBS?
Spectrum
+ sound
SuperCam is used to study Rocks at
distance
7
SuperCam on Mars 2020
Dr. Steven J. Rehse / W hat is LIBS?
Spectrum
+ sound
SuperCam is used to study Rocks at
distance
8
Microphone science goals 1 atm, Air
Pa/√ Hz
4 m
7.5 mbars, CO 2
10 2 Freq (Hz) 10 4
Rovers Sounds
Microphone will record LIBS impacts up to 4 meters
The science objectives of the Mars Microphone are:
1) To support the LIBS investigation to obtain unique properties of Mars
rocks and soils through their coupling with the LIBS laser.
2) To contribute to basic atmospheric science: wind, convective vortices, dust
devils studies at close distance or when interacting with the rover.
3) To monitor various artificial sounds.
9
Microphone accommodation
RWEB (External view)
MTB3-B
MIC + PT1000
MIC-FEE
FEE + Cover
RWEB (External view) Mast unit (Interior view)
Post + Microphone
10SuperCam EQM Model
11287 level of compaction of 6 tonnes. For the higher levels, the amplitude remains
behaviour follows the variation of the Vickers Hardness indicating that the Vick
What can we learn froma critical
LIBS acoustics?
288
parameter influencing the acoustic signal.
289
(Murdoch et al, 2018, submitted)
ablated mass
distance
0.015
0.01
2t
Pressure (Pa)
3t
0.005 4t
6t
8t
0
velocity of 10 t
peak-to-peak acoustic wave
15 t
-0.005
amplitude of acoustic front
waveform (pressure
-0.01
gap)
0 0.2 0.4 0.6 0.8 1 1.2
Time (ms)
The intensity of the acoustic signal acquired as the
peak-to-peak amplitude of acoustic waveform Waveforms of JSC1 targets at different levels of
Figure 15: Waveforms of JSC1 targets at di↵erent levels of compaction as measured by the microph
isproportional to the ablated masses (Chaléard et al., the targets. Eachcompaction
line represents theas measured
average signal overby the around
10 shots microphone atof1.5
the 300th shot m
the acquisi
1997; Grad and M ozina 1993) from the targets.
The mass ablated is obtained from the acoustic signal
The sound peak amplitude increases with the hardness
amplitude . 290 5.3. Analysis of the target craters
of the material
291 The resulting JSC-1 impact craters were analyzed with a microscope (Olympu
The LIBS acoustic signal constraints the material hardness
nification factor x100) and the pictures are represented in Fig. 16. The averag
292
293 the crater in the direction of the laser beam is 828 ± 23 µm. There is no signifi
294 resulting crater diameter with the target compaction (< 3 %). Unfortunately, the 4
12 18Bandwidth of acoustic signals on Mars
n Frequency ranges of the different signals to be calibrated
MICROPHONE BANDWIDTH (100 Hz – 10 kHz)
LIBS acoustics
(0.5-5 kHz)
N elke an d V ary, 2 0 1 4 Rover activities (1-10 kHz)
Vortices (10 Hz to 1 kHz) for vortex diameters 1 – 30 m
Aeroacoustics (1 Hz to 500 Hz) for wind speeds < 20 m/s, object sizes > 1 cm Saltation
(5-10 kHz)
Dynamic pressure (all frequencies) but drops off rapidly with increasing frequency
10 0 10 1 10 2 10 3 10 4
FREQUENCY (Hz)Microphone Radiation issues
n Microphone gain had decreased sharply after X-ray inspections
n All other operations (Shocks, Serialization, retinning) have no impact on
performance
n All flight/qualification microphones have been exposed to X-ray
n Need of another lot
Blue curves (light and dark): no X-ray inspection
Other curves: X-ray inspection
14Calibration: End to end
Objectives:
n Verify the gains of the instrument in the windy
Martian environment
n Ensure microphone is not saturated by Aeolian
noise
Test details:
n Use of AWTSII 2010 Martian
wind tunnel foreseen (2m x
2m x 0.9m) in Denmark
n LIBS-like sound + MIC
operation + Martian
atmosphere over a sufficient
distance, with wind.
Arhus wind tunnel, Denmark
n Target: Spring 2017
15Aarhus end-to-end validation tests
16To summarize
n There will be a microphone on Mars 2020 (FM delivered in
february 2018, Supercam FM this fall)
n You can hear sounds on Mars (even if it’s tough)
n You can do science with it !
Arm
MOXIE
Wheels
+ other engineering noise Helicopter
17Thanks to :
CNES
ISAE-SUPAERO
IRAP
LANL
JPL
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