1. OSIRIS Horst Uwe Keller and the OSIRIS Team
M42 Orion Nebula colour composite
Horst Uwe Keller
and the OSIRIS Team
26. Rosetta SWT – 11./12. June 2009 at ESTEC
Max-Planck-Institut für Sonnensystemforschung

2. OSIRIS Team Activities
Team status
Recent OSIRIS operations
Support of PC9
Instrument status
Shutter MRB support
Safe mode observed at Steins
NAC functional problems
Resulting ongoing actions
Onboard S/W extensions to improve exception handling
Onboard S/W code review in co-operation with IDA
Presentation of Steins results at Spring AGU mtg. in Toronto
OSIRIS

3. Team Status
New Co-Investigator: Monica Lazzarin (University of Padua, Italy)
OSIRIS

4. Activities Since Last SWT
PC9
Passive Checkout (nominal)
Two interactive passes in March 2009 used to test a root cause hypothesis for the NAC shutter problem
OSIRIS

5. Shutter Performance Analysis
Team-wide detailed investigation (review) still ongoing (lead H. Sierks)
detailed ab initio analysis of shutter properties and behaviour: mechanics and operations s/w
Support of ESTEC mechanism department
Goal to demonstrate performance during last upcoming Earth fly-by
OSIRIS

6. NAC shutter NAC shutter issues seem to comprise 3 related anomalies:
1. The NAC shutter safe mode condition triggered at Steins
2. The NAC functional problems observed at Steins
3. The NAC performance problem
OSIRIS

7. NAC shutter safe mode
Preliminary analysis of NAC safe mode at Steins confirmed
The failure was caused by a timing issue that was not taken into account by the s/w and caused the shutter electronics FPGA to report a wrong hardware state because the state changed after the relevant encoder to readout
The failure mechanism is now understood
A modified IFSW shutter error handling module is ready for uplink
OSIRIS

8. NAC functional anomaly
The MRB investigations point to a single deficiency causing the locking problems of the NAC shutter (preliminary)
It seems that the “home” (starting) position of the shutter blades is not well defined
A cure is straight forward by an extra push before the actual image exposure
This is being tested
Impact on operations is a reduction of image repetition rate, about 1.2 s of extra latency are needed
ESTEC 10./
OSIRIS

9. NAC performance
Uncertainty of exposure time due to opening between shutter blades during back travel
Can be solved by use of the “back travel brake”
additional hardware introduced shortly before launch
functional application successfully tested
safe operational handling still being commissioned (looks very promising)
OSIRIS

10. Onboard S/W
Extensions to allow better exception handling have been developed
Implementation of the home push
Code review in collaboration with IDA
S/W update expected during PC10
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11. Future Activities Upcoming activities Unchanged since last SWT PC10
ESB3
It is very likely that we will update IFSW in connection with PC10
Unchanged since last SWT
Plain file handling (implement sequences for simple handling)
Autonomous action on SREM particle flow implemented and tested, but not enabled as threshold is to be tuned
EPS (Experiment Planning System) modeling out of sync with OSIRIS flight software
(Input to SOC delivered)
OSIRIS