Thermal Conductivity of the Martian Soil at the InSight Landing site from HP$^{3}$  Active Heating Experiments

Grott, M.; Spohn, T.; Knollenberg, J.; Krause, Christian; Hudson, T. L.; Piqueux, S.; Müller, N.; Golombek, M.; Vrettos, Christos; Marteau, E.; Nagihara, S.; Morgan, Paul; Murphy, J.; Siegler, M. A.; King, Scott D.; Smrekar, S. E.; Banerdt, W. B.

doi:10.1002/essoar.10506340.1

Cited by 13 publications

(36 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We solely focus on the first 50 sols of the mission to avoid: (a) possible seasonal cycles of dust removal and redeposition (Newman & Richardson, 2015;Szwast et al, 2006;Vicente-Retortillo et al, 2018); (b) seasonal atmospheric trends such as radiatively active clouds that impact surface temperatures near the equator (Wilson & Guzewich, 2014;Wilson et al, 2008); (c) heat contribution from deeper layering that would manifest itself over seasonal times scales (Edwards et al, 2011;Piqueux et al, 2019;Putzig & Mellon, 2007a); (d) and the complicating effect of the regional dust storm (Plesa et al, 2016;Streeter et al, 2019) that occurred near Sol 50 (Banfield et al, 2020). Our results complement other analysis efforts focused on measurements acquired during/after several Phobos transits (i.e., focusing on the top few 100's of μm to mm of the surface layer; Mueller et al, 2021;, on long term seasonal trends probing deeper into the subsurface, and in situ thermal conductivity/diffusivity measurements (Grott, Spohn, Knollenberg, Krause, Hudson, et al, 2021;Grott, Spohn, Knollenberg, Krause, Nagihara, et al, 2021).…”

supporting

confidence: 76%

“…In contrast, the less mature soil at the edge of the hollow, where the RAD measurements are performed, maybe closer to the intra-crater, less evolved material. Nonetheless, a direct thermal conductivity measurement (Grott, Spohn, Knollenberg, Krause, Hudson, et al, 2021) suggests that the soil thermophysical properties are similar at the RAD spot and near the lander. 8.…”

Section: Discussionmentioning

confidence: 99%

“…Overall, beneath the far RAD spot, we conclude that a possible subsurface configuration consistent with these results corresponds to a low conductivity top layer a few hundreds of microns to mm in thickness, on top of a nearly cohesionless fine sand layer at least 4 cm thick. These results will become increasingly valuable to understand the subsurface structure of the Martian soil when interpreted in conjunction with the Phobos transits cooling results Mueller et al, 2021), and the deeper in situ conductivity measurements by the mole (Grott, Spohn, Knollenberg, Krause, Hudson, et al, 2021;Grott, Spohn, Knollenberg, Krause, Nagihara, et al, 2021).…”

Section: Layeringmentioning

confidence: 96%

“…Finally, a highly cemented soil (TI bot = 600 J m −2 K −1 s −1/2 , corresponding to ∼1% cement; Mellon et al, 2008) that would potentially match geological observation (Figure 4b) could be present, but it would have to be buried below nearly two diurnal skin depth or more (i.e., 8 cm with a typical apparent thermal inertia of 183 J m −2 K −1 s −1/2 ) of lower thermal inertia material in order to remain unnoticeable from surface temperature observations. Analysis of active soil heating and associated thermal conductivity measurement of the top ∼40 cm of soil excludes this configuration (Grott, Spohn, Knollenberg, Krause, Hudson, et al, 2021;Grott, Spohn, Knollenberg, Krause, Nagihara, et al, 2021).…”

Section: Layeringmentioning

confidence: 99%

See 3 more Smart Citations

Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

et al. 2021

Self Cite

View full text Add to dashboard Cite

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport mission (InSight; Banerdt et al., 2020) landed on Mars in Elysium Planitia, on November 26, 2018, with the goal of understanding the formation and evolution of terrestrial planets through the investigation of the interior structure of Mars. To meet these objectives, the lander carries multiple instruments, including the Heat Flow and Physical Properties Package (HP 3 ;Spohn et al., 2018) that consisted of a penetrator, colloquially referred to as "the mole," a tether equipped with platinum resistance temperature sensors (TEM-P), and a suite of Abstract Measurements from the InSight lander radiometer acquired after landing are used to characterize the thermophysical properties of the Martian soil in Homestead hollow. This data set is unique as it stems from a high measurement cadence fixed platform studying a simple well-characterized surface, and it benefits from the environmental characterization provided by other instruments. We focus on observations acquired before the arrival of a regional dust storm (near Sol 50), on the furthest observed patch of soil (i.e., ∼3.5 m away from the edge of the lander deck) where temperatures are least impacted by the presence of the lander and where the soil has been least disrupted during landing. Diurnal temperature cycles are fit using a homogenous soil configuration with a thermal inertia of 183 ± 25 J m −2 K −1 s −1/2 and an albedo of 0.16, corresponding to very fine to fine sand with the vast majority of particles smaller than 140 μm. A pre-landing assessment leveraging orbital thermal infrared data is consistent with these results, but our analysis of the full diurnal temperature cycle acquired from the ground further indicates that near surface layers with different thermophysical properties must be thin (i.e., typically within the top few mm) and deep layering with different thermophysical properties must be at least below ∼4 cm. The low thermal inertia value indicates limited soil cementation within the upper one or two skin depths (i.e., ∼4-8 cm and more), with cement volumes <<1%, which is challenging to reconcile with visible images of overhangs in pits.Plain Language Summary InSight carried a six-channel radiometer used to measure diurnal surface temperatures over the duration of the mission. Surface temperatures are controlled by insolation and the microscopic physical properties of the soil (typical grain size, density, degree of soil cementation, or internal layering) that could not be resolved without a microscope or other instruments. Because the InSight lander does not have any systematic way to interrogate the soil, we have instead analyzed these temperature data and characterized the near-surface soil properties. We found that the soil structure near the lander is homogeneous within the top few cm, and is made of loose sandy material with very little to no cementation. These properties are consistent with those derived from orbit before landing using remote sensing technique...

show abstract

supporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Layeringmentioning

confidence: 96%

Section: Layeringmentioning

confidence: 99%

See 2 more Smart Citations

Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The numerical code and data necessary to reproduce the results of this paper have been made publicly available in Grott (2021).…”

Section: Data Availability Statementmentioning

confidence: 99%

Thermal Conductivity of the Martian Soil at the InSight Landing Site From HP³ Active Heating Experiments

et al. 2021

Self Cite

View full text Add to dashboard Cite

The martian near surface layer consists of sand-sized as well as dust-sized particles (Christensen & Moore, 1992) interspersed with larger rocks, and its detailed structure depends on the deposition process as well as subsequent surface modifications by eolian and fluvial activity. Under present martian atmospheric conditions sand-sized particles in the 100-600 μm size range can be moved by winds through saltation (Kok et al., 2012), and dust particles of typical sizes around 1.5 μm are suspended in the atmosphere and can reach the ground in the form of airfall (Lemmon et al., 2019), such that aeolian processes are generally recognized to be the prevalent surface modification process on Mars today.

show abstract

Interiors of Earth-Like Planets and Satellites of the Solar System

Breuer¹,

Spohn

Hoolst

et al. 2021

Surv Geophys

View full text Add to dashboard Cite

The Earth-like planets and moons in our solar system have iron-rich cores, silicate mantles, and a basaltic crust. Differentiated icy moons can have a core and a mantle and an outer water–ice layer. Indirect evidence for several icy moons suggests that this ice is underlain by or includes a water-rich ocean. Similar processes are at work in the interiors of these planets and moons, including heat transport by conduction and convection, melting and volcanism, and magnetic field generation. There are significant differences in detail, though, in both bulk chemical compositions and relative volume of metal, rock and ice reservoirs. For example, the Moon has a small core [~ 0.2 planetary radii (RP)], whereas Mercury’s is large (~ 0.8 RP). Planetary heat engines can operate in somewhat different ways affecting the evolution of the planetary bodies. Mercury and Ganymede have a present-day magnetic field while the core dynamo ceased to operate billions of years ago in the Moon and Mars. Planets and moons differ in tectonic style, from plate-tectonics on Earth to bodies having a stagnant outer lid and possibly solid-state convection underneath, with implications for their magmatic and atmosphere evolution. Knowledge about their deep interiors has improved considerably thanks to a multitude of planetary space missions but, in comparison with Earth, the data base is still limited. We describe methods (including experimental approaches and numerical modeling) and data (e.g., gravity field, rotational state, seismic signals, magnetic field, heat flux, and chemical compositions) used from missions and ground-based observations to explore the deep interiors, their dynamics and evolution and describe as examples Mercury, Venus, Moon, Mars, Ganymede and Enceladus.

show abstract

Thermal Conductivity of the Martian Soil at the InSight Landing site from HP$^{3}$ Active Heating Experiments

Cited by 13 publications

References 48 publications

Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

Thermal Conductivity of the Martian Soil at the InSight Landing Site From HP³ Active Heating Experiments

Interiors of Earth-Like Planets and Satellites of the Solar System

Contact Info

Product

Resources

About

Thermal Conductivity of the Martian Soil at the InSight Landing site from HP$^{3}$ Active Heating Experiments

Cited by 13 publications

References 48 publications

Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements