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

IWF/ÖAW

Thank you

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