ESA Science & Technology - No. 29 - First Interference Scenario

OSIRIS functional commissioning was successfully completed. ROSINA could carry out the high voltage commissioning of DFMS, but the RTOF high voltage commissioning was not completed due to a yet to be understood problem. The problem manifested itself in repeated error messages and occasional autonomous switch offs of the sensor.  Due to this unexpected behaviour it was decided at the last minute that ROSINA would not participate in the Interference Scenario activities planned for the day after.

The Interference Scenario was successfully carried out on 20 and 21 September. It comprised two full days of operations of all the instruments together, with alternating operating modes. Analysis of the results is ongoing, in preparation for the second slot which is planned for mid October.

Due to a configuration problem in the New Norcia station, about 30 minutes of science telemetry were lost from several of the instruments during the pass on 20 September. One instrument, CONSERT, lost about 2 hours of data, whilst others like ALICE and OSIRIS were hardly affected by the TM interruption.

The second part of the Pointing Scenario started on 23 September, with the first two observations involving spacecraft slewing at different solar aspect angles to measure stray light. Various instruments participated in these first observations: OSIRIS, VIRTIS, ALICE, GIADA, MIDAS, MIRO and RPC. Most of the produced science data were dumped in the following New Norcia Pass.

A problem occurred on 18 September during the dump of OSIRIS functional data: the SSMM dump stopped due to a corrupted packet in the packet store. Recovery of all data was successful via manual intervention from the ground.

Full daily passes over the New Norcia station were taken throughout the week, with the addition of one weekly pass of 4 hours over a DSN station (DSS-24) on 22 September.

The table below shows a chronology of the main activities in the reporting period:

At the end of the last New Norcia pass in the reporting period (DOY 268) Rosetta was at 72.8 million km from the Earth. The one-way signal travel time was 4 minutes 3 seconds.