Line heat-source measurements of the thermal conductivity of porous H2O ice, CO2 ice and mineral powders under space conditions

Seiferlin, K.; Kömle, Norbert I.; Kargl, Günter; Spohn, Tilman

doi:10.1016/0032-0633(96)00068-2

Cited by 62 publications

(35 citation statements)

References 28 publications

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“…Heat transfer by vapour transport was not included in the calculation because the temperatures considered (<200K) are low enough to be negligible (Seiferlin et al, 1996). Heat transfer by radiation was shown to be very small in section 2.4 inside the anchor and has been noted by Thomas and Spohn (2002) as negligible for comet ice at the low temperatures we consider here.…”

Section: The Comet Ice Modelmentioning

confidence: 96%

“…Many attempts have been made to model the thermal conductivity of porous ice using textural information (Seiferlin, 1990). Porosity only becomes an important factor at temperatures above 200 K due to heat transfer across the pore space by convection and radiation (Seiferlin et al, 1996). In our work we can keep things simple due to the low temperatures used and model the texture only with the dimensionless Hertz factor, h.…”

Section: The Comet Ice Modelmentioning

confidence: 99%

“…The probe has to be driven slowly into a sample avoiding large stresses on the structure and so is unsuitable for a planetary surface that is poorly characterised or if inserted at high speed. See Seiferlin et al (1996) for a short review and application of the technique to the measurement of the conductivity of ice and mineral powders under space conditions. The hot wire method is similar to the probe method except the heating element doubles up as a temperature sensor.…”

Section: Introductionmentioning

confidence: 99%

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Computer modelling of a penetrator thermal sensor

Paton

Kargl

Ball

et al. 2010

Advances in Space Research

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The Philae lander is part of the Rosetta mission to investigate comet 67P/Churyumov-Gerasimenko. It will use a harpoon like device to anchor itself onto the surface. The anchor will perhaps reach depths of 1-2 m. In the anchor is a temperature sensor that will measure the boundary temperature as part of the MUPUS experiment. As the anchor attains thermal equilibrium with the comet ice it may be possible to extract the thermal properties of the surrounding ice, such as the thermal diffusivity, by using the temperature sensor data. The anchor is not an optimal shape for a thermal probe and application of analytical solutions to the heat equation is inappropriate. We prepare a numerical model to fit temperature sensor data and extract the thermal diffusivity. Penetrator probes mechanically compact the material immediately surrounding them as they enter the target. If the thermal properties, composition and dimensions of the penetrator are known, then the thermal properties of this pristine material may be recovered although this will be a challenging measurement. We report on investigations, using a numerical thermal model, to simulate a variety of scenarios that the anchor may encounter and how they will affect the measurement.

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Section: The Comet Ice Modelmentioning

confidence: 96%

Section: The Comet Ice Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Computer modelling of a penetrator thermal sensor

Paton

Kargl

Ball

et al. 2010

Advances in Space Research

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“…Seiferlin et al, 1996 ;Banaszkiewicz et al, 1997 ). The surface conductivity can be estimated from surface thermal inertia (the product of the square root of conductivity and thermal capacity; e.g.…”

Section: Thermal Conductivity and Capacitymentioning

confidence: 99%

Planetary heat flow from shallow subsurface measurements: Mars

Cornwall

2016

Planetary and Space Science

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“…Nevertheless, theoretical calculations to fit experimental results by Seiferlin et al (1996) (considering gas flow throw pores also) give values for h that range from 0.001 to 0.01. This interval for h is the usual one used in some thermophysical models (e.g.…”

Section: Parameters and Model Calculationsmentioning

confidence: 99%

Effects of irregular shape and topography in thermophysical models of heterogeneous cometary nuclei

Gutiérrez

Ortiz

Rodrigo

et al. 2001

A&A

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Abstract. Several improvements in the thermophysical model by Gutiérrez et al. (2000) have been included in a new code to specifically deal with fully irregular cometary nuclei. Also, the new code allows for the inclusion of regions with different ice to dust ratios, regions of different albedos and regions of different emissivity. The new model has been applied to groups of irregular bodies characterized by 3 statistical parameters, the so-called Gaussian random shapes. In simulations, these bodies rotate steadily around their maximum inertia moment axes. The results of the runs show that the main conclusions of Gutiérrez et al. (2000) still hold, and some new features are observed: 1) In general, very irregular objects have higher water production rates than spheres of the same radius for most of the orbital period. The fact that an irregular object has a larger area than the sphere cannot explain the differences in water production. The main differences appear to be a consequence of its topographic features. Also, topography can diminish the pre-and post-perihelion asymmetries in the lightcurves. Concerning the results for plausible albedo and icy fraction area distributions, 2) the mean water production of a comet with an albedo distribution on the surface is equal to the water production of a homogeneous comet with an albedo equal to the mean albedo of the distribution. The same result is obtained for icy fraction area distributions. 3) Close to perihelion, objects with icy fraction area distributions have nearly the same productions as fully water ice objects. 4) The largest diurnal oscillations in the synthetic lightcurves result from the irregular shape, whereas albedo and icy fraction area inhomogeneities induce oscillations of only a few percent.

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Line heat-source measurements of the thermal conductivity of porous H2O ice, CO2 ice and mineral powders under space conditions

Cited by 62 publications

References 28 publications

Computer modelling of a penetrator thermal sensor

Computer modelling of a penetrator thermal sensor

Planetary heat flow from shallow subsurface measurements: Mars

Effects of irregular shape and topography in thermophysical models of heterogeneous cometary nuclei

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