SESAME Status, Science goals and On-Comet Activities K. Seidensticker1, H.-H. Fischer2, K. Thiel2, I. Apathy3, W. Schmidt4 and the SESAME team 1DLR (Köln) , 2University of Köln, 3KFKI (Budapest), 4FMI (Helsinki)

Outline of Talk Flight operation Software Past activities, vibrations and PC #4 Software Flight SW, AliBaba and Commanding SW Hardware, documents and meeting Funding and personnel SESAME science objectives and measurements SESAME objectives and Rosetta science themes On-Comet operation aspects Conclusions 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Flight operation: Last activities Standard operation: SESAME Cruise Functional Test as part of Philae Extended AFT PC Dates Remarks 29. Mar. 2005 OK! External vibration measured 1 4. Oct. 2005 OK! External vibration measured, strong 6.7 Hz beat on two axes. All foot temperatures below -106.8°C 2 7. Mar. 2006 OK! External vibrations measured: Frequencies from 90 to 200 Hz 3 29. Aug. 2006 OK! External vibrations measured: Frequencies from 70 to 150 Hz. Higher foot temperatures 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

External vibrations Possible signal sources: Orbiter reaction wheels High gain antenna Solar arrays SESAME internal effect etc. Further analysis reasonable CASSE sensitivity Vibration pathways Orbiter monitoring Preparation for flywheel interference test FFT of CASSE ACC signal from foot -Y, x-axis. Philae Checkout #1 (4. Oct. 2005) Insert: Time series (total duration : 1000 ms) Vibrations at 117.7 and 124.3 Hz ==> beat with 6.7 Hz 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Next Activities: Philae Checkout #4 Planned SESAME procedures (LIORs): Cruise Functional Test 2 (CFT-2) Upgraded CFT, performs CASSE Listening before Sounding Vibration Analysis (LSE-VA) Various Listening commands for better vibration characterisation; also suitable for Philae flywheel IF test WOL-Measurement (LSE-WM) Attempt to measure vibration and rotation changes caused by Rosetta WOL CASSE Calibration: Gain (LSE-CCG) Sequence to verify amplifier settings and ADC curve; sound transfer from foot -Y to foot +X through folded landing gear EEPROM Refresh (LSE-EERE) Back-up: Software upload 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

PC #4: WOL sequences SESAME procedure WOL (ca. 2 hrs) Rosetta timeline Thruster firing observed with ROSINA /COPS during Rosetta reaction wheel offloading (WOL) From ROSINA web-site: http://www.phim.unibe.ch/rosina/cops/cops.html SESAME procedure LSE-VA LSE-WM LSE-VA Thruster firing Rosetta timeline WOL (ca. 2 hrs) 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Flight software: Status and Upgrade Flight software FM 1 is running flawlessly (within the known limits) Major upgrade as version FM 2 (improved on-comet operation) CASSE: New Triggered Mode: detection of external signals like cometary quakes and MUPUS-PEN insertion CASSE: Fixing of wrong channel assignment (due to FPGA program flaw) DIM: Autonomous measuring depending on dust flux and sensor status PP: Improved data sampling strategy for PP active and passive modes General: HK data content improved; time-stamp included; science data processing revised FM 2 release during first half of 2007 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Ground Software EGSE software “AliBaba” for SESAME Goals: Quick-look data check (science data and HK) For all hardware versions in use (FM, GRM, lab) Browsing on telemetry level Version 1.2.0 ready Fully qualified for all PC #4 SESAME procedures Planned AliBaba upgrades Improved presentation of PP and DIM data Improved service for lab operation: handle increasing file size Export of instrument data (PDS format: TBD) Adaptation to flight software version FM 2 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

S/W: Commanding and Instruments Operation planning and commanding tool Resource calculation for CASSE operation during PC #4 LIORs CASSE Jobcard generator New program planned Generation of commands and command sequences (LIORs) Calculation of resources (data volume, power, duration) Calculation of related parameters to optimize command settings Instruments PP: Conversion software from SESAME raw-data (rolbin) to complex permittivity functions for any Philae geometry developed. 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Hardware SESAME Central Electronics (CE) SESAME Lab Landing Gear DIM Upgrade of SESAME EQM2-CE; for lab measurements New SESAME GRM2-CE (flight functionality) For further flight software development New CASSE GRM2-PCB delivered in May 2006 (compatible to Philae GRM PCB) SESAME Lab Landing Gear Revised feet; new harness; integration of PP and CASSE sensors DIM Enhanced Ground Support Equipment (EGSE) (flight quality) Flight evaluation, calibration and model improvement Lander GRM-PCB modification for full flight compatibility Removal of over-current protection PP PP Lab-GRM PCB flight compatible 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Documents ESA Archive Interface Control Document (EAICD) One common document for CASSE, DIM and PP Version 0.50 (RO-LSE-DS-3102) delivered to SONC in November 2005 Progress stopped due to limited man-power. Next version after PC #4 (TBD) Interaction Document (RO-LSE-TN-3403) Describes SESAME interaction with other Lander units Release of draft version 4.3 after discussion with MUPUS team 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Meetings 1. Post-Launch SESAME workshop MUPUS - SESAME interaction 12. - 14. October 2005, KFKI, Budapest Status, scientific results, S/W and operation planning MUPUS - SESAME interaction 16. February 2006 Improved data interface agreed Draft version of upgraded interaction document delivered 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Funding and Personnel CASSE / SESAME DIM PP Large changes at DLR possible; people and test units relocation? Personnel: DLR: K. Seidensticker (PI), K. Gusbeth (student, Ground S/W), Univ. Köln: K. Thiel, H.-H. Fischer (Co-Is, Flight S/W, operation) DIM New Co-Investigator: M. Podolak (Tel Aviv University) Personnel (KFKI AEKI): I. Apáthy (PI), A. Péter, diploma student; A. Juhász (Co-I, KFKI RMKI) PP In-house funding for Rosetta support, external funding for special activities on application Personnel: FMI: W. Schmidt (PI), M. Genzer (operations), J. Ryno (S/W support); Co-Is: ESTEC: H. Laakso, R. Trautner; CETP: M. Hamelin 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

CASSE: Science Objectives and Measurements LSE-CAS-O1: Determine elastic properties of cometary surface layer LSE-CAS-O2: Determine macro-structure of surface layer (layering, inhomogeneities) LSE-CAS-O3: Locate and analyze micro-seismic events Measurements LSE-CAS-M1: Determine longitudinal and shear wave velocities by active sounding from foot to foot LSE-CAS-M2: Generate reflection and refraction seismograms by active sounding (CASSE and MUPUS-Pen) LSE-CAS-M3: Register external signals with several sensors (Passive listening) Relation to other Instruments MUPUS: Use MUPUS-PEN hammering as external vibration source SD2: Use SD2 drilling as external vibration source (TBD) 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

DIM: Science Objectives and Measurements LSE-DIM-O1: Study the fluxes and dynamics of near-surface cometary particle flow LSE-DIM-O2: Determine physical properties of cometary grains LSE-DIM-O3: Contribute to the understanding of cometary activity and the formation of cometary mantles Measurements LSE-DIM-M1: Measure parameters of the electrical signal caused by particle impact on piezo-electric plate LSE-DIM-M2: Determine average signal height in case single impacts can not be discriminated LSE-DIM-M3: Determine flow rate and direction as well as temporal variations Relation to other Instruments GIADA: Correlate DIM data with GIADA observations (TBD) 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

PP: Science Objectives and Measurements LSE-PP-O1: Determine electrical properties of the cometary surface matter and its evolution LSE-PP-O2: Monitor electron density variation and the comet’s outgassing activity Measurements LSE-PP-M1: Inject alternating currents of different frequencies into the cometary surface and monitor variations of induced electrical potential (active mode) LSE-PP-M2: Monitor potential difference variations (passive mode) Relation to other Instruments ROMAP: Compare permeability measurements MUPUS: PP electrode deployment; temperature of surface matter APXS: PP electrode deployment; surface composition CIVA: Observation of MUPUS-Pen and Philae soles 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

SESAME and Rosetta Science Themes 1 1. Global Characterization of the Nucleus D. Near Surface Distribution of Minerals, Organics and Ices LSE-CAS-O1, LSE-DIM-O2, LSE-DIM-O3 E. Internal Nucleus Structure LSE-CAS-O2, LSE-PP-O1 2. Composition of the Nucleus Material A. Composition of Near-surface Minerals LSE-DIM-O2 C. Composition of Near-surface Ices LSE-DIM-O2, LSE-PP-O1 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

SESAME and Rosetta Science Themes 2 3. Physical Properties of Nucleus Material A. Microphysical Properties of the Nucleus Material LSE-CAS-O1, LSE-DIM-O2 B. Electric and Magnetic Properties of the Nucleus Material LSE-PP-O1 D. Mechanical Properties of the Nucleus Material LSE-CAS-O1 4. Development of Cometary Activity A. Properties of Regions Emitting Gas and Dust LSE-CAS-O3, LSE-DIM-O1, LSE-DIM-O3 B. Temporal Evolution of the Surface and Inner Coma LSE-CAS-O2, LSE-CAS-O3, LSE-DIM-O3, LSE-PP-O2 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

SESAME and Rosetta Science Themes 3 5. Composition of Coma and Tail Material C. Composition of Solid Particles LSE-DIM-O2 6. Physical Properties of Coma and Tail Material C. Physical Properties of Solid Particles 7. Interaction of Cometary Material with its Interplanetary Environment B. Properties of the Ionosphere LSE-PP-O2 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

On-comet operation Draft versions (straw-man) of command sequences Descent First Science Sequence (FSS) Long-term operation Next years: development and test of additional measurement and operation methods => further upgrade of flight software Development of software planning tool for command generation and resource calculation 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

Operational interaction and constraints CASSE MUPUS: MUPUS-Pen used as a moving signal source during insertion (hammering) SD2: Signal source during drilling (TBD) Flywheel: Impact on CASSE operation to be measured during cruise phase PP APX: Transmitter electrode; no operation during PP measurements MUPUS: Transmitter electrode; no operation during PP measurements 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006

A difficult way to 67P/C-G: Conclusions Slow progress due to limited resources Software (flight and ground) upgrades are needed for full use of hardware Improving operation and analysis methods, e.g.: CASSE: Analysis of seismograms DIM: More precise impact model PP: More calibration work Complex permittivity vs. ice concentration, composition, temperature Detailed modelling of electrode configuration Definition of SESAME science goals and measurements 2nd Post-Launch Philae Experimenters Workshop Helsinki, 4. - 6. September 2006