HFI operations

All satellite operations including the HFI instrument ones are under ESA MOC responsibilty for obvious safety reasons. The HFI instrument operations are nevertheless delegated to the HFI Instrument Operations Team (IOT) built from the HFI consortium and under the HFI Principal Investigator responsibility. Instrument management, operations and parameter monitoring are thus prepared and controlled by the IOT and serviced by MOC either in near real time during the DTCP or uploaded in the satellite mission timeline for defered execution. The HFI instrument health and science data quality has been monitored daily by the IOT from launch till the end of the HFI extension mission phase. Apart from ground based tests, different operations phases did occur:

• 14/05/2009-18/05/2009 Launch Early Operational Phase
• 18/05/2009-09/07/2009 Commissioning Phase. The operations during this phase were under ESA's Planck Project responsibilty. The main HFI activities have been functional tests of the instrument and its cooldown till 100 mK. Given the performance, the helium flow has been set to the minimal one giving an End Of Life estimation second half of January 2012.
• 10/07/2009-12/08/2009 Calibration and Performance Verification Phase. The operations during this phase were under ESA's Planck Science Office responsibilty. The main HFI operations have been performance tests and activities to mesure the effects of several systematics. The only instrument failure happened the 6th of August were the electronic part of the 4K cooler has been switched off probably due to a major cosmic particle. It has to be noted that no tuning of the HFI parameters have been executed in flight till the end of the full HFI mission, excepted in December 2009 for an adjustment of the on-board numerical compression parameters.
• 12/08/2009-28/11/2010 HFI Nominal mission
• 28/11/2010-13/01/2012 HFI Extended mission
• 13/01/2012-(to be continued) LFI "only" extension phase

The detailled operation timeline for HFI is given in this annex.