Fly-By Working Group Meeting OSIRIS Fly-By Working Group Meeting Padova February 4/5, 2010 Holger Sierks Max-Planck-Institut für Sonnensystemforschung sierks@mps.mpg.de

Osiris Fly-By Working Group - Agenda Thursday, Feb 4 Lutetia fly-by preparations 09:00 Welcome 09:10 Lutetia in a nutshell; wrap-up by Colin Snodgrass and by UPD 09:20 'Lutetia cratering history' by Simone Marchi 09:30 Fly-by geometry and timeline, break points – latest updates by Michael Kueppers 09:50 Discussion of current input to Lutetia science planning Basis: spreadsheets and comments distributed by Olivier and Laurent exposure time comments by Uwe, comments by Sonia Observations overview/wrap-up by Richard Moissl Lutetia early light curve Satellite search Shape determination Phase function High-res imaging Adjourn Conversion to timeline, exposure time guidance, imaging cadence 11:00 Coffee break

Osiris Fly-By Working Group - Agenda 11:30 Hardware insert (due to presence of mechanism team) NAC Shutter brake test plan overview by Richard Moissl Brake commissioning Light tightness analysis Friction determination A/B point selection/optimization SHM MRB close out readiness WAC shutter parameters 13:00 Lunch break 14:30 Discussion and distribution of work packages for data processing and evaluation Lutetia light curve Shape by light curve inversion Satellite search Dust Global shape reconstruction

Osiris Fly-By Working Group - Agenda Stereo, elevation maps Photometric properties, surface regolith properties Surface geomorphology Age determination Surface composition Space weathering Physical properties Context with VIRTIS 16:00 Coffee break 16:30 Calibration status wrt Lutetia data analysis, overview by Cecila Tubiana Data reduction ESB3 results as relevant for Lutetia WAC straylight Open issues 17:30 Wrap-up discussion of current planning status (=> telecon /w LAM and others) 18:30 Adjourn 19:45 Dinner (ristorante Ai Navigli)

Osiris Fly-By Working Group - Agenda Friday, Feb 5 Lutetia fly-by preparations cont’d OSIRIS hardware as relevant for Lutetia planning cont’d 09:00 Discussion of Lutetia planning cont’d 10:00 Status WAC reference camera WAC FS shutter rework WAC filter wheel WAC front door wiring WAC return to Osiris Reference System Status of OSIRIS power converter issue Short status report Risk assessment (preliminary) Impact for Lutetia sequence planning 11:00 AOB 11:30 Adjourn

Lutetia Working Groups Package Theme Osiris Working Group 1 Lutetia light curve S. Mottola, C. Tubiana, LAM 2 Shape by light curve inversion LAM, S. Lowry (tbc), C. Snodgrass, J.B. Vincent 3 Satellite search, dust P. Gutierrez, I. Bertini, R. Moissl, S. Schroeder, C. Snodgrass, F. Marzari, W. Sabolo 4 Exosphere (Na, OH) C. Grava, M. Kueppers, C. Snodgrass, F. Ferri 5 Global shape reconstruction LAM, S. Casotto, E. Simioni, W. Sabolo, P. Gutierrez 6 Stereo, elevation maps C. Snodgrass, R. Moissl, G. Cremonese, E. Simioni, LAM 7 Photometric properties, surface regolith properties, Space weathering L. Lara, J. de Leon, A. Barucci, S. Spjuth, M. Lazzarin, S. Magrin, F. Ferri, I. Bertini, S. Schroeder, P. Vernazza, C. Lerat, R. Brunetto, S. Fornasier, B. Carry, S. Marchi, Wing Ip, P. Vernazza, LAM 8A Surface geomorphology S. Marchi, M. Massironi, F. Ferri, S. Besse 8B Surface features (the unknown) S. Besse, LAM 10 Age determination S. Marchi, F. Marzari, M. Massironi, S. Mottola, M. Kueppers 11 Surface composition C. Snodgrass, S. Marchi, M. Lazzarin, S. Magrin, A. Migliorini, L. Lara, J. de Leon, A. Barucci 12 Moved to WP7 13 Physical properties L. Lara, J. de Leon, M. Lazzarin, S. Magrin, F. Ferri, A. Barucci, Wing Ip, LAM 14 Context with VIRTIS C. Tubiana, L. Lara, J. de Leon, F. Ferri, A. Migliorini, A. Barucci (VIRTIS Co-I), M. Lazzarin, LAM

Power Converter Issue In July, 2009, a high power event was detected during validation of sequences for ESB #3 on the Osiris reference system at MPS No immediate thread was found (inspection, logs review) ESB #3 validation runs continued after power cycle NAC shutter issue was detected, we swapped in QM shutter Inspection revealed that the NAC shutter was in fail safe (blocked in half open position), as was the WAC front door (permanent open position) High power event was a failed reset of power converter consumer switches (heaters, s/s, fail-safe mechanisms) Side bar: failed to readout NAC CCD in fail-safe mode

Power Converter Issue

Power Converter Issue Root cause: Flight spare PCB on Osiris reference system used a ceramics and a tantalum capacitor to control main and redundant wake-up timing (different temperature slopes) 2 degC elevated temperature in clean room plus high level of activities with a number of power cycles created perfect match for crash on FS Crash on data and address bus during initial wakeup of main and redundant controllers cause lack of zeros at time of switch reset Sequence of latches to reset determines uncontrolled fail safe activations: NAC shutter, WAC FD, NAC FD, WAC shutter Timing is sharp: need min. 50 usec gap, have 300us on flight Osiris Flight Osiris PCB used tantalum caps on main and redundant side First temperature tests with flight lot tantalum caps reveals a give or take ~100 usec/10deg -> 20 degC leeway around RT

Power Converter Issue

Power Converter Issue AFT (flight temperature range) is -30 to +40 degC -> no way to go to low temperatures ! Flight rule in place now for +20 +/- 20degC at switch on, goal +-15 Characterization of a Rosetta s/c heater (5W) on EBox will help, but not suffice May need to tilt s/c @ comet approach (s/c is cold) to warm up +Y-panel (violation of s/c flight rules wrt solar panel sun incidence angle) Investigation on board/component level is ongoing Procured 300 pcs of flight identical capacitors from Vishay (manufacturer) Started temperature tests to investigate statistical spread of capacity decrease versus temperature within a fabrication lot Caps are excellent, to spec (+/- 10%), we are looking for half a per cent deviation! ESA project is informed, meeting at ESTEC held in January 2010 MRB with ESA to come in March/April 2010 (end of temp tests)

Power Converter Issue Conclusions (preliminary): In principle, risk is limited if temp at switch-on is close to +20C (reduce turn-on temperature range) In principle, risk is limited if temp at switch-on was already seen in flight (and close in time) However, capacitors age. As do DC/DC converters. So safe T-regime today might not be safe after 10 yrs in flight (or after 5 yrs – today) Further reduction in temperature range is requ’d Risk will remain throughout the mission Iteration with ESA/MOC, ESA QA/parts; MRB ongoing For Lutetia (and PC12 and others): Ensure turn-on temperature is ok (hard requirement) Limit number of switch-ons, best to 1 per campaign If power cycle is unavoidable, wait min. 1 h for thermal equilibrium on power converter board (avoid gradients on converter board)