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…Report at Midterm Meeting April 11 2006

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Development of a melting probe for Mars and Europa

Norbert I. Kömle

Project overview

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…Scientific Goals Scientific Goals

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Explore vertical layering of deep ice sheets under low pressure conditions

CompositionTextureDust contentTraces of organics

Reconstruct geological history and climate evolution

of planetary bodies

Thermal propertiesOptical propertiesElectrical propertiesDensityPressure

Geocryology for icy moons and planets

Overview Overview M

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•Administration

•Characterization of targets

•Scientific requirements

•Technical requirements

•Payload candidates

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…Administration Administration

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September 06 2005

Kickoff Meeting IWF Graz

November 2005

ESTEC contract signed by all parties (ÖAW, ESTEC)

Dr. Erika Kaufmann 100 % working contract funded from project (current funding period: 12 months)

November 2005 -April 2006

Draft documents created:

TARGET CHARACTERIZATION, SCIENTIFIC REQUIREMENTS AND PAYLOAD CANDIDATES

MECHANICAL AND THERMAL DESIGN

ELECTRONICS DESIGN

February 06 2006 First melting test in vacuum with existing probe

April 11 2005 Midterm Meeting IWF Graz

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… Targets Targets

diameter 6794 km

mass 0.108 ME

solar distance 1.52 AU

max. solar radiation 591 W/m2

gravitational acceleration

0.38 g

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MARS

EUROPA diameter 3138 km

mass 0.008 ME

solar distance 5.20 AU

max. solar radiation 51 W/m2

gravitational acceleration

0.134 g

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…Target description: MARS Polar Areas Target description: MARS Polar Areas

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North perennial ice cap South perennial ice cap

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…Target description: EUROPA 1 Target description: EUROPA 1

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Interior structure

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…Target description: EUROPA 2 Target description: EUROPA 2

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Triple bands and ice cracks

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…Target description: EUROPA 3 Target description: EUROPA 3

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Suspicion: Around ice cracks ice layer may be thin

Access to subsurface oceanby means of a melting probe?

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…Technical requirements for first prototype Technical requirements for first prototype

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Use of standard components for electronics: Cross section not too small, chosen dimensions: diameter 6 cm, length 20 cm

Length of tether: ca. 30 m (long enough to test functionality of tether deployment and internal power dissipation

Power supply: 28V, 70W maximum (to avoid use of high voltage components in laboratory testing

Payload: Simple strawman payload, A/D conversion of sensor data inside probe and data transfer through power cable

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…Payload Candidates Payload Candidates

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Temperature sensors

housekeeping and natural temperature profile during non-heating periods (evaluation of thermal properties)

Tilt sensorshousekeeping (reconstruct path of probe in the ice)

ISFET chemical sensorsPH-value of meltwater, trace elements

Miniature mass spectrometer (Open University)

elemental composition

Miniature TOF mass spectrometer (Physikalisches Institut, Uni Bern)

elemental composition

CBD-densitometer

(Open University)

material density around by measuring Compton backscattering of a gamma source

Optical/IR sensorsalbedo variations along melt path as indicator for contaminations

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…Present status of prototype construction Present status of prototype construction

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Item Status

Mechanical design drawings ready

Electronics design under consideration, partially ready

Mechanical parts for prototype ordered

Electronics parts for prototype ordered, partially available

Components for tether partially available

Heater foils (MINCO) available

PT100 sensors (MINCO) available

ADXL tilt sensor available

ISFET PH sensor available

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…First melting test at IWF: 06-02-2006 First melting test at IWF: 06-02-2006

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Temperature evolution of different parts of melting probe

and ice sample during the experiment

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…Test results Test results

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Heating power: 60 W

Ice temperature: -30°CHot tip temperature when in contact with ice: 30°CHot tip temperature after loss of ice contact: > 130°CTemperature of probe rear end (still outside ice): 80°C

Power of 70 W appropriate for 6 cm cross sectionLaunch pad must be improvedRear end may become too hot as long as probe not fully inside ice

Lessons from test: