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IWF/ÖAW
Main task Understanding the physics of planetary near-surface layers, including
comets, Mars & Moon
Main research topics Study of the mechanisms controlling the “activity” of comets by
theoretical modelling as well as experimental simulation in a cryo-vacuum environment
Development of prototypes for surface in situ measurements of key parameters (thermal conductivity, electrical permittivity, mechanical properties)
Participation in ESA comet mission Rosetta/Philae and NASA Mars mission InSight
Refereed publications (since Jan 2013):Total: 4 (first author: 4)
Educational activities (since Jan 2013): Diploma theses: 3 Lecturing at University of Graz
Planetary Surfaces
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IWF/ÖAW
Lead: Norbert Kömle
Members
Staff: M. Bentley, G. Kargl, W. Macher
Master Students: B. Krebl (thesis completed), A. Schaffer, P. Tiefenbacher
Cooperation within IWF
MIDAS Group: Cometary dust
Key international collaboration
Germany: Institut für Planetenerkundung, DLR BerlinPoland: Space Research Centre, Polish Academy of Sciences, WarsawUK: Planetary Research Institute, Open University, Milton Keynes
Who are we?
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MIDAS Operations and Science
MIDAS is an amplitude modulated Atomic Force Microscope Dust particles are collected, located, and imaged Data are nm-resolution 3D images (height fields) Full-time operations start early May
IWF/ÖAW
Pressure distribution near the exitof an elongated ice filled crack
Surface erosion causing deepening of the crystallization front
Surface ice sublimation
Dynamics of phase changes
Downward motion of crystallization front
Amorphous ice crystallization?
Modeling of Cometary Crevasses
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Krebl B. and Kömle N.I.: A two-dimensional model of crevasses formed by cometary activity. Planet. Space Sci., 87, 46-65 (2013).
IWF/ÖAW
Robust Thermal Conductivity Probes
Perform tests and calibration experiments in different materials
Multiple probes (2 or 4 needles) to derive thermal properties
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heater needle sensor
needle
Dual probes
IWF/ÖAW
Geometry: two parallel cylinders A and B
Each cylinder is composed of a core and an enclosing coaxial sheath
Surface resistances taken into accountat core/sheath and sheath/sample interface
Advantages of analytic approach
Fast computation; high accuracy
Applicability to fitting of measurement data
Measurement scenario
Pulse heating of A, observation of TA(t), TB(t)
heat capacity and conductivity of sample,surface resistance at probe/sample boundary
Novel Thermal Dual Probe Theory
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Macher W., Kömle N.I., Bentley M.S., Kargl G.: Temperature evolution of two parallel composite cylinders with contact resistances and application to thermal dual-probes, Int. J. Heat and Mass Transfer, 69, 481-492 (2014).
IWF/ÖAW
Pile Driving Models for Soil Penetration
Determination of soil-mechanical properties: Configuration for Philae/MUPUS
hammering device Configuration for InSight Mole Scaling of standard models
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Pile driving model adapted to the „mole“ configuration: Hollow tube driven by
the impact of an interior ram weight
IWF/ÖAW
Rosetta data interpretation after Philae arrival, with emphasis on MIDAS and MUPUS
Future Plans: 2015-2018
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Development of models to integrate MIDAS and MUPUS data into a local (thermal) surface model
Soil-mechanical modelling for the Mars mission InSight evaluation of soil-mechanical parameters from performance data of the InSight mole