Melting Probe Progress Meeting: Summary of the experiments done and their influence on the new design E. Kaufmann, G. Kargl, N. Kömle Space Research Institute of the Austrian Academy of Sciences ESA-Contract Progress Meeting

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Melting Probe Test at Cologne Vacuum conditions Pressure: ~0.3 mbar Sample height: 120 cm Surrounding temperature: -15°C Chamber cooled by LN2 Duration of test: 47h 27 min Experimental Set Up:Thermal Requirements: Heating equipment segmented in 5 regions: F1  Heater H1 F2+F3  Heater H2 F4 ǁ F5 ǁ F6  Heater H3 F7 ǁ F8 ǁ F9  Heater H4 F10 ǁ F11 ǁ F12  Heater H5

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Results and Conclusions from Cologne Approximate penetration velocity: 0.32 cm/h Maximum depth reached: ~15 cm Maximum crater diameter built around Melting Probe: ~ 11 cm Thermal output at the tip of the melting probe head to low. Collateral heat dissipation leading to a crater round the Melting Probe Change in design  a further heating circuit closer to the front heater Results:Conclusions:

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Melting Probe - Modifications Third heating segment inside the tip Additional external and internal temperature sensors no clear measurable refinement  next change in design: heaters fixed at the outer walls, directly or with the help of thin wrappings or plates  first tested with a flat front heater

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Summary of the Flat tip tests 1. Test Heaters sandwiched between brass plates 2. Test Heaters sandwiched between brass plates 3. Test Heating foil (small diameter) fixed outside by gluing 4. Test Heating foil (larger diameter) fixed outside by gluing and covered with copper foil

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Flat tip – Mechanical Design Includes three heating circuits: Heater 1: between the two brass plates Heater 2: between second plate and cylindric part Heater 3: serial electrical circuit of two heating foils fixed at the inner wall of the cylindrical part

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Flat Tip- Measurement I Penetration depth: ~21.5 cm Penetration speed: ~1.77 cm/h God thermal contact due to mechanical fixing  for a more complex geometry this approach is not feasible  new design: foils fixed directly at the front heater Temperature increase in the E-box due to heat dissipated from the cable  new design: flat cable

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Flat Tip- Measurement II Measurement with heating foil fixed at the outer flat surface of the front heater  homogeneous heat flux within the foil not reached  insufficient penetration speed

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Flat Tip- Measurement III Heating foil covered with copper foil  heat transfer improved  penetration speed of ~ 0.45 cm/h measured. Measurement also shows the influence of the surface roughness of the ice and the position of the electrical contacts on the attitude of the probe

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Influence of the Surface Roughness

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Comparison Heater Temperatures – Duty Cycle

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Thermal Model of the Heater

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Pyramidal Tip - Heating Foils Thermal models of two alternative designs of the front heater

Development schedule Prototype 2 Meltingprobe Progress Meeting: ActionDate Delivery time/ duration Order tailored heater foilsNow2 - 3 months Order remaining mechanical parts Now2 months Cable extraction tests October/November months Redesign electronics (include control elements for motor driving mechanical penetration devices) Begin now?2 months Assembly of cable magazineBegin nowFinished until end of year

Melting Probe Progress Meeting: IWF/ÖAW GRAZ Development schedule of Prototype 2 Meltingprobe Progress Meeting: ActionDate Delivery time/ duration Assemble probe for first testFebruary 2008 Order 10 m cable After first tests with 2 m cables 2 months Extended test phase Begin March 2008 Several monthts Use samples including dust One field test to study deeper penetration Begin summer 2008Until end 2008 (end of project)

Melting Probe Progress Meeting: IWF/ÖAW GRAZ