Aerospace Engineering Department SD2: Status and On Comet Science P. Di Lizia, F. Malnati, P. Francesconi, A. Ercoli Finzi, F. Bernelli-Zazzera

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 2  SD2 Status  SD2 Open points  Cruise phase  Post Hibernation phase  Comet phase  First Science Sequence (FSS)  Requirements  Proposed sequence  Long Term Mission (LTM)  SD2 Facility  Perforation Strategy  Test campaign  Preliminary Results Agenda

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 3  In flight tests performed :  Commissioning (4 blocks) –Electronic behaviour tests –Carousel movements –Volume Checker movements  Active checkout ( 3 checkouts) –Carousel movements –Drill rotation –Drill translation –EEPROM refresh  Passive Checkout ( 6 checkouts) –EEPROM content check –Electronics switch on –Position resolvers switch on SD2 Status (switch on SD2)OK (4 rotations)OK (2 movements)OK (20 rotations)OK (4 movements)OK (2 movements) OK OK Results

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 4  Fully commissioned:  All mechanical items of SD2 have been tested during cruise phase SD2 Status Mechanical unit (including Drill) SD2 is ready for comet phase Electronic unit Carousel

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 5  Required (or desired) activities for next active checkouts :  Carousel movements  Drill rotation  Drill translation  EEPROM Refresh (during PC#12) SD2 OPEN POINTS: Cruise phase

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 6  Test definition  Complete test of SD2 is recommended after hibernation Carousel movements Drill rotation movement Drill translation movements EEPROM refresh (Mandatory)  Constraints about Power budget Data rate Access to Rosetta (RF link) Other subsystems and experiments activities SD2 OPEN POINTS: Post hibernation phase  No activities foreseen during SDL phase

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 7  Decisions for both phases: First Science Sequence  How many holes  How many samples from each hole  Which ovens shall be used to release samples  Use of Volume Checker Long Term Mission  Use of SD2 to perform qualitative analysis of mechanical characteristics of comet soil SD2 OPEN POINTS: Comet phase

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 8 SD2 FSS: Requests (1/2)  Reference Documents:  Philae Science Objectives [RO-LAN-L1-1000; Issue 1.1 Draft; January, 02, 2009]  Requests: CIVA M/V Requests# of holes# of samplesDepthOven type ROS-PHI-CIV-FSS-002 Analyze samples from different depths and location 24Different depths (TBD) MTO CIVA M/I Requests# of holes# of samplesDepthOven type ROS-PHI-CIV-FSS-003 Analyze samples from different depths and location 24Different depths (TBD) MTO

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 9 SD2 FSS: Requests (2/2) COSAC Requests# of holes# of samplesDepthOven type ROS-PHI-COS-FSS-003 Collect 2 samples: 1 from deepest location, 1 from surface 12  1 from deepest  1 from surface  1 MTO  1 HTO PTOLEMY Requests# of holes# of samplesDepthOven type ROS-PHI-PTO-FSS-001 Load HTO1 with a surface sample, HTO2 with a sample at maximum depth 12  1 from surface  1 from deepest  2 HTO ROS-PHI-PTO-FSS-002 Load MTO with sample and rotate oven between CIVA and Ptolemy 11TBD  1 MTO ROS-PHI-PTO-FSS-001 Analyze the coma at various epochs/solar distances N.A.  1 HTO

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 10 SD2 FSS: # of holes - # of samples Required Depths SurfaceMax Depth Hole 1 Sample 1  MTO 1 under CIVA M/V  MTO 1 under CIVA M/I Sample 2  HTO 1 under COSAC Sample 3  HTO 2 under PTOLEMY Sample 4  MTO 2 under CIVA M/V  MTO 2 under CIVA M/I – PTOLEMY Sample 5  MTO 3 under COSAC Sample 6  HTO 3 under PTOLEMY Hole 2 Sample 1  MTO 4 under CIVA M/V  MTO 4 under CIVA M/I Sample 2  MTO 5 under CIVA M/V  MTO 5 under CIVA M/I

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 11 SD2 FSS: Proposed Sequence Seq. Description Duration [h] Consumption [Wh] OvenDepthInstrument PTOHTO 0-PTOLEMY H1S1MTO 1SurfaceCIVA H1S2HTO 1SurfaceCOSAC H1S3HTO 2SurfacePTOLEMY H1S4MTO 2MaxCIVA-PTOLEMY H1S5MTO 3MaxCOSAC H1S6HTO 3MaxPTOLEMY H2S1MTO 4SurfaceCIVA H2S2MTO 5MaxCIVA Total:  Low Drill translation velocity (2 mm/min) for H1S1 and H2S1, and during drilling to maximum depth  Duration and consumption do not include stand-by phases

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 12 SD2 FSS: Mission Plans; HK, SC Packets  Necessary mission plans: 30 MPDescription# of wordsbit 1  Drill bite rearming  Sample retrieval  Sample release  Drill down  high and low velocity  to surface and maximum depth  Ovens’ positioning Total:  House-keeping (HK) and Science (SC) Packets Packet# of packetsMbit HK SC

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 13 How to sample the comet Drilling phaseSampling phase Discharge phase Sampling tube Drill bite Comet soil Oven

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 14 SD2 Scientific Instrument Correlation analysis between drill telemetry data and the mechanical characteristics of the perforated material Tool Scientific Instrument (material parameters) = f (telemetry data) ? Experimental approach SD2

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 15 SD2 DIA Facility (Laboratory) Strain gauge equipped with an amplifier and the conditioning system Current sensor DC Power Supply Low-pass digital filter Data Acquisition device Labview Software MATLAB SD2 DIA Facility

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 16 Simulation of different sampling scenarios, according to different on comet surface conditions. SD2 Facility - Specimen GRAPHITIC-FOAM MULTI-LAYER GASBETON

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 17 Perforation strategy - Material Characteristics GASBETON Fragile material Low density (~500 kg/m3) Porous composition GRAPHITIC-FOAM Fragile material Low density (560 kg/m3) Porous composition

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 18 The contact between cutting and surface is asymmetrical, with an asymmetrical distribution of cutting stress 1)Test 20° 2)Test 60° F C FLFL Simulation of SD2 operation on irregular cometary surface Test campaign - I nclined surface

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 19 Goal: Drill behaviour analysis (discontinuity of force and torque) First layer: mix of concrete material Second layer: gasbeton Test campaign - Multi-layers specimen

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 20 First layer: dry graphitic-foam Second layer: frozen graphitic-foam Goal: Drill behaviour analysis (discontinuity of force and torque) Test campaign - Multi-layers specimen

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 21 Minimum Rotation Speed Experimental campaign with different specimen categories: Imposition of decreasing drill rotation speed values Identification of the minimum rotation speed required to drill the specimen without stepper motor stop Creation of a DATABASE of correlations between minimum speed value and the material characteristics Perforation strategy - Experimental Approach

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 22 Test campaign - Gasbeton Gasbeton drilling: Ct = 4 Vt = 10 Cr = 1 Vr = 18

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 23 Drill Rotation speed levels Drill Translation speed levels Test campaign - Gasbeton

RLSW #4 Venice 2009 Aerospace Dep. Pierluigi Di Lizia 24 Preliminary Results  SD2 could be used as a scientific instrument in order to retrieve qualitative mechanical information about comet soil  The procedure about the soil analysis is both time and power consuming  Several mission plans need to be uploaded  Several laboratory tests must be implemented:  The database about different soil mechanical characteristics  The correct sequence of drilling test in order to perform the test in best way without risk  It could be useful in case of some failure of other experiments (backup solution)

Aerospace Engineering Department SD2: Status and On Comet Science P. Di Lizia, F. Malnati, P. Francesconi, A. Ercoli Finzi, F. Bernelli-Zazzera