title: In situ methods for measuring thermal properties and heat flux on planetary bodies.
abstract: The thermo-mechanical properties of planetary surface and subsurface layers control to a high extent in which way a body interacts with its environment, in particular how it responds to solar irradiation and how it interacts with a potentially existing atmosphere. Furthermore, if the natural temperature profile over a certain depth can be measured in situ, this gives important information about the heat flux from the interior and thus about the thermal evolution of the body. Therefore, in most of the recent and planned planetary lander missions experiment packages for determining thermo-mechanical properties are part of the payload. Examples are the experiment MUPUS on Rosetta's comet lander Philae, the TECP instrument aboard NASA's Mars polar lander Phoenix, and the mole-type instrument HP(3) currently developed for use on upcoming lunar and Mars missions. In this review we describe several methods applied for measuring thermal conductivity and heat flux and discuss the particular difficulties faced when these properties have to be measured in a low pressure and low temperature environment. We point out the abilities and disadvantages of the different instruments and outline the evaluation procedures necessary to extract reliable thermal conductivity and heat flux data from in situ measurements.
authors.affiliation: Space Research Institute, Austrian Academy of Sciences, Graz, Austria.
authors.forename: Norbert I
authors.initials: NI
authors.lastname: Kömle
authors.forename: Erika S
authors.initials: ES
authors.lastname: Hütter
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Macher
authors.forename: Erika
authors.initials: E
authors.lastname: Kaufmann
authors.forename: Günter
authors.initials: G
authors.lastname: Kargl
authors.forename: Jörg
authors.initials: J
authors.lastname: Knollenberg
authors.forename: Matthias
authors.initials: M
authors.lastname: Grott
authors.forename: Tilman
authors.initials: T
authors.lastname: Spohn
authors.forename: Roman
authors.initials: R
authors.lastname: Wawrzaszek
authors.forename: Marek
authors.initials: M
authors.lastname: Banaszkiewicz
authors.forename: Karoly
authors.initials: K
authors.lastname: Seweryn
authors.forename: Axel
authors.initials: A
authors.lastname: Hagermann