C. Krause

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

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M. Grott

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

Tilman Spohn

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

W. B. Banerdt

Jet Propulsion Laboratory

J. Knollenberg

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

T. L. Hudson

Jet Propulsion Laboratory

S. E. Smrekar

Jet Propulsion Laboratory

M. P. Golombek

Jet Propulsion Laboratory

N. Müller

Radboud University Nijmegen

Eloïse Marteau

Jet Propulsion Laboratory

Philippe Lognonné

Université Paris Cité

Cooperative Institutions

Centre National de la Recherche Scientifique

Japan Aerospace Exploration Agency

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

Jet Propulsion Laboratory

Institute of Space and Astronautical Science

Planetary Science Institute

Planet

California Institute of Technology

The University of Tokyo

Université Paris Cité

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The Camera of the MASCOT Asteroid Lander on Board Hayabusa 2

Space Science Reviews (2016)

R. Jaumann Nicole Schmitz Alexander Koncz H. Michaelis Stefan Schroeder

Orbiter

Regolith

10.1007/s11214-016-0263-2

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Citations (50)

The first active seismic experiment on Mars to characterize the shallow subsurface structure at the InSight landing site

Nienke Brinkman Cédric Schmelzbach David Sollberger Martin van Driel Jan ten Pierick

In November 2018, the InSight lander successfully touched down in the Elysium Planitia plain on Mars. Since then, two scientific instruments were deployed directly onto the surface of Mars: (1) SEIS, a package consisting of two three component seismic sensors and (2) HP3, the heat flow and physical properties package. HP3 includes a self-hammering penetrator (mole) that hammers itself into the subsurface of Mars to a maximum depth of five meters. The mole hammering generates seismic signals that are recorded by SEIS and can be used to image the shallow subsurface just below the landing site. Even though not included in the level-one mission's objectives, this opportunistic seismic experiment is, to the best of our knowledge, the first active seismic experiment ever conducted on a different planet. Here, we discuss the most important aspects of the implementations of this opportunistic experiment. Presentation Date: Monday, September 16, 2019 Session Start Time: 1:50 PM Presentation Start Time: 3:30 PM Location: 301B Presentation Type: Oral

Mars landing

10.1190/segam2019-3215661.1

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Citations (10)

Constraints on the shallow elastic and anelastic structure of Mars from InSight seismic data

Nature Geoscience (2020)

Philippe Lognonné W. B. Banerdt W. T. Pike Domenico Giardini Ulrich R. Christensen

Seismometer

Microseism

Seismic Noise

10.1038/s41561-020-0536-y

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Citations (263)

Direct observations of asteroid interior and regolith structure: Science measurement requirements

Advances in Space Research (2017)

Alain Hérique Benoit Agnus Erik Asphaug A. Barucci Pierre Beck

Regolith

Planetary science

10.1016/j.asr.2017.10.020

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Citations (65)

The Heat Flow and Physical Properties Package (HP3) for the InSight Mission

Space Science Reviews (2018)

Tilman Spohn M. Grott S. E. Smrekar J. Knollenberg T. L. Hudson

The Heat Flow and Physical Properties Package HP3 for the InSight mission will attempt the first measurement of the planetary heat flow of Mars. The data will be taken at the InSight landing site in Elysium planitia (136 ∘E, 5 ∘N) and the uncertainty of the measurement aimed for shall be better than ±5 mW m−2. The package consists of a mechanical hammering device called the "Mole" for penetrating into the regolith, an instrumented tether which the Mole pulls into the ground, a fixed radiometer to determine the surface brightness temperature and an electronic box. The Mole and the tether are housed in a support structure before being deployed. The tether is equipped with 14 platinum resistance temperature sensors to measure temperature differences with a 1- $\sigma $ uncertainty of 6.5 mK. Depth is determined by a tether length measurement device that monitors the amount of tether extracted from the support structure and a tiltmeter that measures the angle of the Mole axis to the local gravity vector. The Mole includes temperature sensors and heaters to measure the regolith thermal conductivity to better than 3.5% (1- $\sigma $ ) using the Mole as a modified line heat source. The Mole is planned to advance at least 3 m—sufficiently deep to reduce errors from daily surface temperature forcings—and up to 5 m into the martian regolith. After landing, HP3 will be deployed onto the martian surface by a robotic arm after choosing an instrument placement site that minimizes disturbances from shadows caused by the lander and the seismometer. The Mole will then execute hammering cycles, advancing 50 cm into the subsurface at a time, followed by a cooldown period of at least 48 h to allow heat built up during hammering to dissipate. After an equilibrated thermal state has been reached, a thermal conductivity measurement is executed for 24 h. This cycle is repeated until the final depth of 5 m is reached or further progress becomes impossible. The subsequent monitoring phase consists of hourly temperature measurements and lasts until the end of the mission. Model calculations show that the duration of temperature measurement required to sufficiently reduce the error introduced by annual surface temperature forcings is 0.6 martian years for a final depth of 3 m and 0.1 martian years for the target depth of 5 m.

Regolith

10.1007/s11214-018-0531-4

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Citations (132)

Apollo lunar heat flow experiment revisited: A critical reassessment of the in situ thermal conductivity determination

Journal of Geophysical Research Atmospheres (2010)

M. Grott J. Knollenberg C. Krause

Lunar heat flow was determined in situ during the Apollo 15 and 17 missions, but some uncertainty is connected to the value of the regolith's thermal conductivity, which enters as a linear factor into the heat flow calculation. Different approaches to determine the conductivity yielded discordant results, which led to a downward correction of the obtained heat flow values by 30%–50% subsequent to the publication of the first results. We have reinvestigated likely causes for the observed discrepancies and find that neither poor coupling between the probe and regolith nor axial heat loss can explain the obtained results. Rather, regolith compaction and compression likely caused a local increase of the regolith's thermal conductivity by a factor of 2–3 in a region which extends at least 2–5 cm from the borehole wall. We conclude that the corrected lunar heat flow values, which are based on thermal diffusivity estimates sampling a large portion of undisturbed regolith, represent robust results. Future in situ measurements of regolith thermal conductivity using active heating methods should take care to both minimize regolith disturbance during probe emplacement and maximize heating time to obtain reliable results. We find that for the Apollo measurements, heating times should have exceeded at least 100 h, and ideally 200 h.

Regolith

Heat flow

10.1029/2010je003612

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Citations (58)

Seasonal Variations of Soil Thermal Conductivity at the InSight Landing Site

Geophysical Research Letters (2023)

M. Grott S. Piqueux Tilman Spohn J. Knollenberg C. Krause

Abstract The heat flow and physical properties package measured soil thermal conductivity at the landing site in the 0.03–0.37 m depth range. Six measurements spanning solar longitudes from 8.0° to 210.0° were made and atmospheric pressure at the site was simultaneously measured using InSight's Pressure Sensor. We find that soil thermal conductivity strongly correlates with atmospheric pressure. This trend is compatible with predictions of the pressure dependence of thermal conductivity for unconsolidated soils under martian atmospheric conditions, indicating that heat transport through the pore filling gas is a major contributor to the total heat transport. Therefore, any cementation or induration of the soil sampled by the experiments must be minimal and soil surrounding the mole at depths below the duricrust is likely unconsolidated. Thermal conductivity data presented here are the first direct evidence that the atmosphere interacts with the top most meter of material on Mars.

Martian soil

Soil thermal properties

10.1029/2023gl102975

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Citations (4)

Calibration of the HP³ Radiometer on InSight

Earth and Space Science (2020)

Nils Mueller J. Knollenberg M. Grott E. Kopp Ingo Walter

Abstract The Heatflow and Physical Properties Package (HP 3 ) radiometer is currently operating on Mars, observing two spots approximately 1 and 3 m north‐north‐west of the InSight lander. The instrument has primary sensors that are sensitive in the range of 8 to 14 μm and two more sensors with more narrow spectral ranges per field of view. The radiometer underwent radiometric and geometric calibration at DLR—Berlin; and on Mars radiometric self‐calibration is performed regularly. The self‐calibration confirms that one of the two primary sensors has been stable since the ground calibration, but environmental parameters that are likely associated with the thermal contact of sensor and instrument main body may have slightly changed. The other primary sensor has increased in sensitivity for an unknown reason but is still within expectation from the sensor design. The uncertainty of the two primary sensors is approximately 3 K at night, with somewhat larger errors in the late afternoon. This estimate includes the effect of sensitivity changes that would be too small to be reliably detected by the self‐calibration.

Radiometry

Radiometric Calibration

Radiometric dating

10.1029/2020ea001086

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Citations (25)

Calibration of the Heat Flow and Physical Properties Package (HP) for the InSight Mars Mission

Earth and Space Science (2019)

M. Grott Tilman Spohn J. Knollenberg C. Krause Marco Scharringhausen

Abstract The (HP ) of the InSight Mars mission is an instrument package to measure the Martian geothermal heat flow. The instrument's platinum resistance temperature sensors have been calibrated between 75 and 55 °C, and the absolute temperature uncertainty of the calibration is 10 mK. Temperature differences can be measured with an uncertainty of better than 5 mK. HP determines regolith thermal conductivity by using the HP mole as a modified line heat source, and thermal conductivity can be measured with an uncertainty of better than 4%. Tilt sensors used to determine the attitude of the mole during penetration measure tilt with an uncertainty of better than 0.25°.

Heat flow

10.1029/2019ea000670

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Citations (12)

Mars Soil Temperature and Thermal Properties From InSight HP3 ${\mathrm{H}\mathrm{P}}^{3}$ Data

Geophysical Research Letters (2024)

Tilman Spohn N. Müller J. Knollenberg M. Grott M. Golombek

Abstract Diurnal and seasonal variations in soil and surface temperature measured with the thermal probe and radiometer of NASA's InSight Mars mission are reported. At a representative depth of 10–20 cm, an average temperature of 217.5 K was found, varying by 5.3–6.7 K during a sol and by 13.3 K during the seasons. From the damping of the temperature variation with depth and the phase shift, a thermal diffusivity of (3.93 0.39) × /s was derived for the upper 10 cm from the diurnal temperature variation and of (3.63 0.53) × /s for the 40 cm depth range of the mole from the annual temperature variation. Using published thermal conductivity and inertia values together with the diffusivities, soil densities of 1,470 and 1,730 kg/ were derived for these depths. The temperatures allow the deliquescence of thin films of brine, the efflorescence of which may explain the cemented duricrust observed.

10.1029/2024gl108600

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Citations (0)