sesame status k. seidensticker 1 , h.-h. fischer 1 , m. knapmeyer 2 , k. thiel 3 ,

4th Philae Science Workshop

Venice, 30 March - 1 April 2009

SESAMECASSE • DIM • PP

SESAME Status

K. Seidensticker1, H.-H. Fischer1, M. Knapmeyer2, K. Thiel3,I. Apathy4, W. Schmidt5 and the SESAME team

1DLR (Köln) , 2DLR (Berlin), 3University of Köln, 4KFKI (Budapest),5FMI (Helsinki)



SESAMECASSE • DIM • PP Outline of Talk

Recent flight operations• PC8, Steins Flyby and Thermal Characterization 2

Flight Software FM-3

CASSE lab experiments

Operation planning until Hibernation

Preview on comet operations

Funding and personnel

Conclusions



SESAMECASSE • DIM • PP Recent Flight Operations: PC8

Fit of Flywheel vibration spectrum(Speed 10 = 9923 rpm)



SESAMECASSE • DIM • PP Recent Flight Operations: THC2

+Z Orbiter

+X Orbiter

+X Lander

175 ° 192 °

+Z Lander

Sun illumination during THC2

Sole temperature profiles during third run of procedure LSE_TCHAR obtained with a preliminary calibration derived from Steins Flyby data. The Orbiter slew maneuver to position 192° started at 14:00

SCET.



SESAMECASSE • DIM • PP Operation Summary

Flywheel Listening• CASSE: Strong vibration (≥ factor 30 above RW background), mainly at

fundamental frequency and harmonics; CASSE data used for new calibration of FW rotation rate.

• DIM: No interference observed

• PP: Broad electrical noise; lines at FW speed and higher frequencies; PP operation is corrupted above 8000 rpm (> speed 00).

Temperature Calibration• Preliminary calibration achieved; data base complete after THC2; final

evaluation pending

CDMS and Telemetry• Large improvement compared to PC6 (no data corruption; only one

science packet lost during PC8)




Flight Software FM-3

Major upgrades implemented / planned for SW FM-3• CASSE: Fixing of wrong channel assignment (due to FPGA program flaw:

missing reset)

• CASSE: Automatic adjustment of gain and trigger levels

• CASSE: Stacking of sounding measurements for improved S/N ratio

• CASSE: Improved synchronization means for Listening of MUPUS-Pen insertion (better time resolution, evaluation of MUPUS-PEN depth information)

• DIM: Autonomous measuring depending on dust flux and sensor status

• General: Temperature measurements with extended range (<= -105 °C)

FM-3 shall be uploaded during PC #10 (September 2009)




CASSE Lab Experiments: August 2008

General Setup CASSE Piezo Source & Receiver

MUPUS-Pen Simulator

Source




Seismic Section Visualization

CASSE Lab Experiments: Analysis

New software tools developed for evaluation

SpectrogramsSpectrograms

Trace SynchronizationTrace Synchronization

Trace StackingTrace Stacking

Bootstrap Error EstimatorsBootstrap Error Estimators

Particle Motion VisualizationParticle Motion Visualization

Poisson Numberfrom Wadati Diagrams

Poisson Numberfrom Wadati Diagrams

(synthetic example)(synthetic example)




CASSE Lab Experiments: Results

330.9273

325.3263

319253

v [ms-1]T [K]

Air Wave Velocities

Shielding the air wave from the MUPUS-Pen simulator was not possible. We could demonstrate that the main recorded signal traveled at air sound velocity.

Future Experiments will need:• Improved mounting of MUPUS Simulator• Air wave shielding• Infinite medium (no box walls!)• Testing the influence of ground contact variation• Improved software, e.g. for synchronization

Distance from source vs. sound arrival times



SESAMECASSE • DIM • PP SESAME Cruise Phase Operations

PC6: FM-2 upload

PC8: 1. Flywheel test, thermal calibration 1

Steins flyby: Thermal calibrationTHC2: Thermal calibration 2PC10: FM-3 upload, tests, CASSE calibration

PC12: Flywheel test, interference testsLutetia flyby: Search for IDPs

2014: Checkout, FM-4 upload?




Operation Planning until Hibernation I

PC10 Operations• Upload flight software FM-3 (SCrOP requirement SES_4)

• CFT-4 (also test of FM-3) (SES_16)

• CASSE Calibration 2 (also test of FM-3) (SES_14)

• WOL Measurement 3 (also test of FM-3) (SES_9)

ESB3 Operations replaced by Thermal Characterization 2

(SES_10)




Operation Planning until Hibernation II

PC12 Operations• Repeat of Flywheel Test with automatic gain setting. Flywheel

in descent mode? (SES_7) Touchdown detection possible?

• Interference Tests (SES_5)

• CASSE Calibration 3 (SES_14)

• WOL Measurement 3 (SES_9)

Lutetia Operations• Search for IDPs (SES_11) (Flight through Hill sphere)

• Thermal Calibration 3 (SES_10)




Preview on Comet Operations: In Orbit

CASSE: Detect cometary ice-dust particles

DIM: Determine particle flow rate and direction

DIM: Determine particle properties (velocity, radius,

elastic

parameters etc.)

PP: Monitor outgassing activity




Preview on Comet Operations: SDL

CASSE: Register landing impact => elastic / inelastic parameters

CASSE: Calibrate sound transfer via unfolded landing gear

DIM: Determine particle flow rate and direction vs. height

DIM: Determine particle properties vs. height


PP: Calibrate sensor properties with unfolded landing gear




PP Calibration during Descent

Measurements of stray capacitances between cables / sensors and structure in vacuum and with the unfolded landing gear

PC8 current measurements

Induced potential variations

Parameters to be characterized during descent while still under near vaccuum conditions




Preview on Comet Operations: FSS (+ LTS)

CASSE: Determine elastic properties of landing site

CASSE: Determine sub-surface structure with MUPUS-Pen

CASSE: Detect and locate micro-seismic events

DIM: Study the near-surface cometary particle flow

DIM: Determine particle properties

PP: Determine electrical properties of the surface

material




SESAMECASSE • DIM • PP Funding and Personnel

CASSE / SESAME• Organizational changes at DLR; thermal-vacuum chambers now at DLR, Bremen

• Personnel:– DLR, PF: K. Seidensticker (PI), M. Knapmeyer (Co-I, part-time, lab and analysis),

DLR, RB-MUSC: H.-H. Fischer (Co-I, part-time, flight S/W, operation)– Univ. Köln: K. Thiel (Co-I, retired)

DIM• Funding by the Hungarian Space Office through ESA/PECS guaranteed until mid 2013 on a

yearly 9-13 k€ level; additional money requested by MPS (Lindau) from the DLR (Bonn)• Personnel:

– KFKI, AEKI: I. Apáthy (PI), A. Péter (Co-I, engineering) (both retired);A. Péter will be followed by Attila Hirn soon.

– MPS: H. Krüger (Co-I, managing scientist); will follow I. Apathy as DIM-PI– Supporting scientists: A. Juhász (Co-I, KFKI, RMKI), M. Podolak (Co-I, TAU)

PP• In-house funding for Rosetta support, external funding for special activities on application.

• Personnel (no changes):– FMI: W. Schmidt (PI)

Co-Is: ESTEC: H. Laakso, R. Trautner; CETP: M. Hamelin



SESAMECASSE • DIM • PP On the way to 67P/C-G: Conclusions

Upgrades of flight and ground software needed for more

efficient use of hardware and telemetry

Improving analysis methods, e.g.:• CASSE: Further Lab experiments planned; analysis of

seismograms

• DIM: More precise impact model; calibrations

• PP: More calibration work

Low resources and personnel changes lengthen most activities

Delivery of drafts of the SESAME Flight Operation Plan (FOP)

and EAICD planned for the first half of 2009

sesame status k. seidensticker 1 , h.-h. fischer 1 , m. knapmeyer 2 , k. thiel 3 ,

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