A Reconstruction Algorithm for Temporally Aliased Seismic Signals Recorded by the InSight Mars Lander

Sollberger, David; Schmelzbach, Cédric; Андерссон, Фредрик; Robertsson, Johan O. A.; Brinkman, Nienke; Kedar, S.; Banerdt, B.; Clinton, John; Driel, Martin van; Garcia, Raphaël; Giardini, Domenico; Grott, M.; Haag, Thomas; Hudson, T. L.; Lognonné, Philippe; Pierick, Jan ten; Pike, W. T.; Spohn, Tilman; Stähler, Simon C.; Zweifel, Peter

doi:10.1029/2020ea001234

Cited by 7 publications

(20 citation statements)

References 38 publications

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“…Note how the frequency bandwidth of the hammer signal exceeds the Nyquist frequency of 50 Hz of the nominal SEIS acquisition (marked by the dashed line) highlighting the value of the reconstruction method by Sollberger et al. ( 2021 ) …”

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 95%

“…Changing these FIR filters during hammering proved to be critical for successful recording of the hammering signals (Sollberger et al. 2021 ).…”

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 99%

“…In order to reach the necessary high temporal resolution and to record the broad-band hammering signals, we developed a recording and data-processing strategy to overcome the nominal sampling limitations (Sollberger et al. 2021 ). Firstly, the anti-aliasing FIR filters to prepare the seismic data for down-sampling to the highest nominal sampling frequency of 100 Hz were turned-off during seismic acquisition of most hammering sessions.…”

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 99%

“…19 a for two example hammer strokes measured on Mars), the original seismic waveforms can be reconstructed at a high virtual sampling rate using a sparseness-promoting algorithm (Sollberger et al. 2021 ; InSight Mars SEIS Data Service 2020 ).

Fig.…”

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 99%

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The InSight HP3 Penetrator (Mole) on Mars: Soil Properties Derived from the Penetration Attempts and Related Activities

et al. 2022

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The NASA InSight Lander on Mars includes the Heat Flow and Physical Properties Package HP3 to measure the surface heat flow of the planet. The package uses temperature sensors that would have been brought to the target depth of 3–5 m by a small penetrator, nicknamed the mole. The mole requiring friction on its hull to balance remaining recoil from its hammer mechanism did not penetrate to the targeted depth. Instead, by precessing about a point midway along its hull, it carved a 7 cm deep and 5–6 cm wide pit and reached a depth of initially 31 cm. The root cause of the failure – as was determined through an extensive, almost two years long campaign – was a lack of friction in an unexpectedly thick cohesive duricrust. During the campaign – described in detail in this paper – the mole penetrated further aided by friction applied using the scoop at the end of the robotic Instrument Deployment Arm and by direct support by the latter. The mole tip finally reached a depth of about 37 cm, bringing the mole back-end 1–2 cm below the surface. It reversed its downward motion twice during attempts to provide friction through pressure on the regolith instead of directly with the scoop to the mole hull. The penetration record of the mole was used to infer mechanical soil parameters such as the penetration resistance of the duricrust of 0.3–0.7 MPa and a penetration resistance of a deeper layer ($>30~\text{cm}$ > 30 cm depth) of $4.9\pm0.4~\text{MPa}$ 4.9 ± 0.4 MPa . Using the mole’s thermal sensors, thermal conductivity and diffusivity were measured. Applying cone penetration theory, the resistance of the duricrust was used to estimate a cohesion of the latter of 2–15 kPa depending on the internal friction angle of the duricrust. Pushing the scoop with its blade into the surface and chopping off a piece of duricrust provided another estimate of the cohesion of 5.8 kPa. The hammerings of the mole were recorded by the seismometer SEIS and the signals were used to derive P-wave and S-wave velocities representative of the topmost tens of cm of the regolith. Together with the density provided by a thermal conductivity and diffusivity measurement using the mole’s thermal sensors, the elastic moduli were calculated from the seismic velocities. Using empirical correlations from terrestrial soil studies between the shear modulus and cohesion, the previous cohesion estimates were found to be consistent with the elastic moduli. The combined data were used to derive a model of the regolith that has an about 20 cm thick duricrust underneath a 1 cm thick unconsolidated layer of sand mixed with dust and above another 10 cm of unconsolidated sand. Underneath the latter, a layer more resistant to penetration and possibly containing debris from a small impact crater is inferred. The thermal conductivity increases from 14 mW/m K to 34 mW/m K through the 1 cm sand/dust layer, keeps the latter value in the duricrust and the sand layer underneath and then increases to 64 mW/m K in the sand/gravel layer below.

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Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 95%

“…Changing these FIR filters during hammering proved to be critical for successful recording of the hammering signals (Sollberger et al. 2021 ).…”

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 99%

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 99%

Fig.…”

Section: Soil Mechanical and Thermal Properties Derived From Actions ...mentioning

confidence: 99%

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The InSight HP3 Penetrator (Mole) on Mars: Soil Properties Derived from the Penetration Attempts and Related Activities

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“…The so called "flattop" FIR filter used for the VBB sensor during hammering has a different slope above the cutoff filter to avoid clipping of the high-amplitude hammer signal. The SP recorded data are passed through an all-pass FIR filter, the so-called "spike" filter, during hammering and the reconstruction algorithm of Sollberger et al (2021) is applied after the data is downlinked to Earth (Figure B1). Sollberger et al (2021) extensively validated the reconstruction algorithm with synthetic data (see Section 4; Figure 6 in Sollberger et al (2021)).…”

Section: Appendix A: Hp 3 -Seis Clock Correlationmentioning

confidence: 99%

In Situ Regolith Seismic Velocity Measurement at the InSight Landing Site on Mars

et al. 2022

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Interior exploration using Seismic Investigations, Geodesy and Heat Transport's (InSight) seismometer package Seismic Experiment for Interior Structure (SEIS) was placed on the surface of Mars at about 1.2 m distance from the thermal properties instrument Heat flow and Physical Properties Package (HP3) that includes a self‐hammering probe. Recording the hammering noise with SEIS provided a unique opportunity to estimate the seismic wave velocities of the shallow regolith at the landing site. However, the value of studying the seismic signals of the hammering was only realized after critical hardware decisions were already taken. Furthermore, the design and nominal operation of both SEIS and HP3 are nonideal for such high‐resolution seismic measurements. Therefore, a series of adaptations had to be implemented to operate the self‐hammering probe as a controlled seismic source and SEIS as a high‐frequency seismic receiver including the design of a high‐precision timing and an innovative high‐frequency sampling workflow. By interpreting the first‐arriving seismic waves as a P‐wave and identifying first‐arriving S‐waves by polarization analysis, we determined effective P‐ and S‐wave velocities of vP=119−21+45 ${v}_{P}=11{9}_{-21}^{+45}$ m/s and vS=63−7+11 ${v}_{S}=6{3}_{-7}^{+11}$ m/s, respectively, from around 2,000 hammer stroke recordings. These velocities likely represent bulk estimates for the uppermost several 10s of cm of regolith. An analysis of the P‐wave incidence angles provided an independent vP/vS ratio estimate of 1.84−0.35+0.89 $1.8{4}_{-0.35}^{+0.89}$ that compares well with the traveltime based estimate of 1.86−0.25+0.42 $1.8{6}_{-0.25}^{+0.42}$. The low seismic velocities are consistent with those observed for low‐density unconsolidated sands and are in agreement with estimates obtained by other methods.

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In-situ regolith seismic velocity measurement at the InSight landing site on Mars

Brinkman

Schmelzbach

Sollberger

et al. 2022

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The NASA InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) lander touched down at Elysium Planitia on Mars in November 2018. The main goal of the mission is to investigate the internal structure of Mars using seismic, geothermal, and radio science experiments (Banerdt et al., 2020). Two scientific instruments were deployed on the surface of Mars (Figure 1a): (a) The Seismic Experiment for Interior Structure (SEIS) package (Lognonné et al., 2019) that consists of two three-component seismometers to monitor the Martian seismicity (e.g., Clinton et al., 2021;Giardini et al., 2020) and to image the interior of the planet (e.g.,

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A Reconstruction Algorithm for Temporally Aliased Seismic Signals Recorded by the InSight Mars Lander

Cited by 7 publications

References 38 publications

The InSight HP3 Penetrator (Mole) on Mars: Soil Properties Derived from the Penetration Attempts and Related Activities

The InSight HP3 Penetrator (Mole) on Mars: Soil Properties Derived from the Penetration Attempts and Related Activities

In Situ Regolith Seismic Velocity Measurement at the InSight Landing Site on Mars

In-situ regolith seismic velocity measurement at the InSight landing site on Mars

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