MARTIAN
WIND
MICROPHONES

SENSING

WITH

SEISMOMETERS

AND

A. E. Stott1, (alexander.stott@isae-supaero.fr), N. Murdoch1, R. F. Garcia1, M. Gillier1, D. Mimoun1, A.
Spiga2, R. Lorenz3, D. Banfield4, T. Bertrand5, B. Chide6, A. Chavez7, M. De La Torre Juarez7, R. Hueso8,
G. Martinez9, L. Mora Sotomayor10, A. Munguira8, S. Navarro10, C. Newman11, P. Pillieri12, J. PlaGarcia10, J. A. Rodriguez-Manfredi10, A. Sanchez-Lavega8, D. Viudez Moreiras10, N. Williams7, S. Maurice12, R. C. Wiens13, P. Lognonné14
1
ISAE-SUPAERO, Université de Toulouse, FR, 2LMD, Paris, FR, 3Johns Hopkins APL, MD, USA, 4NASA Ames,
CA, USA, 5Paris Observatory, FR, 6LANL, NM, USA, 7JPL /California Institute of Technology, Pasadena, CA, USA.,
8

Universidad del País Vasco (UPV/EHU), Bilbao, Spain, 9Lunar and Planetary Institute, Houston, TX, USA, 10Centro de
Astrobiología (CSIC- INTA), Madrid, Spain, 11Aeolis Research, Chandler, AZ, USA, 12IRAP, Toulouse FR, 13Purdue, IN,
USA, 14IPGP, Paris, FR

Introduction: The wind plays a major part in
the processes shaping Mars to this day [1]. The coupling of the wind with the dust cycle, for example, is
of great importance for the atmospheric dynamics
[1]. To that end, high quality measurements of the
Martian wind are of significant interest. Dedicated
wind sensors have provided in situ measurements of
the wind on the Martian surface. However, other
sensitive instruments offer complementary and new
information on the wind and turbulence. Here, we
will demonstrate how InSight’s seismometer [2] and
Perseverance’s microphone [3,4], can be used for
wind analysis in planetary applications.
Background: The NASA InSight and Perseverance missions have each carried wind sensors which
operate at up to 1 or 2sps (samples per second) respectively [5,6]. InSight’s TWINS instrument [5] has
functioned effectively throughout its over 3-year
mission so far. However, power constraints due to
SEIS

dust deposition on the solar panels have meant
measurements are scarce for the second Martian year
of operation. On the other hand, the Perseverance
rover’s MEDA instrument [6] has acquired data for
around an Earth year so far. Other instruments deployed on Mars missions are also sensitive to the
wind. For example, the seismometer on InSight [2]
and the microphone on the SuperCam instrument
suite for Perseverance [3,4]. These have respectively
recorded vibrations due to wind forcing or pressure
fluctuations, and so offer a new way to examine the
Martian atmosphere.
The InSight seismometer: The InSight seismometer is capable of sensing vibrations of 1.5E-10
m/s^2/rtHz at 0.4Hz and records at up to 100sps [7].
This makes it an ideal tool to observe the dynamic
forcing due to the wind. Fig. 1 shows the signal
power (RMS envelope) of the seismic data for the
first 700 sols compared to the wind speed level
measured by TWINS. There is a clear correlation

Wind speed Boom 1

Wind speed Boom 2

Figure 1: Comparison of InSight seismometer velocity RMS (0.4-1Hz bandwidth) signal to the wind
speed retrieval from both TWINS booms. All signals are normalised.

between the two. This relationship was described in
[8], where the sensitivity of the seismic data to the
wind speed was shown to vary over the Martian sol
and seasons. As pointed out in [9], the change in
relationship is correlated to the type of turbulence
and not just the wind speed, in fact, it follows the
patterns identified in [10]. This is understood by the
fact that the seismometer measures the vibrations
due to wind forcing which, in turn, depend directly
on the turbulent flow.
The seismometer typically records at 20sps and
can record at up to 100sps, higher than the 1sps of
TWINS. Moreover, the TWINS sensor relies on a
calibration grid and complex retrieval algorithm [5].
As a result, combining the seismic data with the
wind data from TWINS can lead to improved wind
estimates in terms of sampling rate and resolution.
The buildup of dust on the solar panels has led to
power constraints becoming tighter throughout the
second Mars year of operations. As a result, the atmospheric sensors have not been able to operate for
the entire time, while the seismometer has been operated almost constantly. This highlights the prospect
of using the InSight seismic data to provide an estimate of the Martian wind when the atmospheric sensors were not recording. This would bolster the InSight wind catalogue to an almost continuous 2 Martian years of data.
The Perseverance microphone: The microphone on the SuperCam instrument suite senses the
sound pressure, which is the deviation from static/ambient pressure. As a result, it is sensitive to the
wind and its variability [1,11,12]. This is demonstrated in Fig. 2, which shows the RMS of a microphone recording overlayed with the wind speed from
the MEDA instrument for the same period.
The microphone can record at up to 100ksps or,
more usually, at 25ksps, both above what is required
for atmospheric observations. As a result, the microphone RMS can be combined with the MEDA wind
sensor to estimate the wind speed at much shorter
time intervals than the MEDA wind sensor alone.
This is exemplified in Fig. 2 where the microphone
derived RMS exhibits more rapid fluctuations. In
fact, the microphone is directly sensitive to the varia-

tion in the wind speed, as well as the wind speed
itself. This has been observed on Earth in [12] which
showed the output of unshielded microphones to be
best correlated to the product of the mean and standard deviation of the wind, according to the turbulent
conditions. Therefore, the microphone can be used
both for high frequency wind estimation and to directly provide information on the wind speed variation, both helpful to study turbulence.
Future network missions: Both atmospheric
and geophysical science goals desire a network of
observatories on Mars (e.g. [13,14]). As we present
here the sensors for both can aid each other’s goals
and so should be proposed together. The atmospheric
measurements are essential to determine whether a
signal is of seismic origin or not [8,9] and to determine the seismicity [9]. As shown here though, the
seismometer contributes directly to atmospheric science goals. Microphones, on the other hand, look at
the highest frequency variation in the atmosphere.
Furthermore, they are relatively cheap and straightforward to operate. The sensor and its electronics are
relatively lightweight and can be operated at lower
sampling rates (down to the 1sps range) to reduce
downlink volume in continuous operations.
Conclusion: We have demonstrated that seismometers and microphones are suitable tools to analyse the wind on Mars, in combination with dedicated wind sensors. In this way we are able to extend
the InSight wind catalogue and also shine a light on
turbulence in terms of forcing. The SuperCam microphone, on the other hand, provides a look at the
high frequency scales of the Martian atmosphere
along with a direct sensitivity to the variability. The
fact that each instrument is complementary while
also being sensitive to a particular aspect of the Martian wind means that they not only provide robustness but also offer estimation quality and additional
information on turbulence. The use of data processing, such as through machine learning, will enable the separation of these facets.
We propose that future network missions should
accommodate both atmospheric and seismology
goals together in order to maximise the possibilities

Figure 2: A plot of the RMS of the microphone signal compared to the wind speed measured by MEDA.

for both communities. The sensors are sensible payloads to attach to missions, for example the sample
return landers, to maximise scientific return.
References:
[1] Newman et al. Science Advances in print ,2022
[2] Lognonné et al. SSR, 2019
[3] Mimoun et al., SSR, Submitted 2022
[4] Maurice et al., SSR, 2021
[5] Banfield et al., SSR 2018
[6] Rodriguez-Manfredi et al. SSR, 2021
[7] Lognonné et al., Nature Geo., 2020
[8] Charalambous et al. JGR Planets 2021
[9] Stott et al. in prep. 2022
[10] Chatain et al. GRL, 2021
[11] Maurice et al., Nature, 2022
[12] Morgan and Raspet, JASA, 1992
[13] Stähler et al., Low-Cost Science mission concepts, 2022
[14] Parfitt et al. EPSC, 2021