ARGOS-3 : Anomaly AR 6555

1. ARGOS-3 : Anomaly AR 6555 • Major Anomaly AR 6555 : Corrupted Argos Mission Telemetry • First occurrence on November 22nd • Telemetry is inconsistent but some characteristic « bytes » of messages can be recognized within the data • All HK parameters are « green », HK blocks that contain detailed software status don’t indicate any specific problem • All other functions of instrument work properly (beacon-instrument protocol, acknowledgement of Master Beacon directives, dump of memory) • Hardware reset on November 24th. Immediately all is OK. • Second occurrence on January 1st. • Telemetry is partly consistent (15 % of messages correct for all types, many ’00’ in the telemetry, most of ‘D60’ are missing though they have been checked by the SW before being written in the FIFO). • ‘Software restart’ on January 11th. Immediately all is OK. • ‘Software restart’ activates also some HW reset (ex : on telemetry FIFO) • Investigation still in progress : problem seems to be located at FIFO or at FPGA level. Telemetry is checked all the time until the writting in FIFO.

2. ARGOS-3 : Anomaly AR 6555 • Consequence of Anomaly 6555 • Implies a HW or SW restart of the instrument • Today, SW doesn’t seem involved (a new version of management SW is not expected therefore uploading is not expected ) • Specific monitoring of Argos Telemetry performed in CLS in order to detect asap the anomaly and to alert CNES then Eumetsat : it could take take several hours during the commissioning phase • Procedure to restart lasts 10 minutes (pass over Svalbard) and needs to be compatible with other EUM operations • Several patchs to be transmitted after each restart : • 2 corrective patchs (via master beacon) • 3 parameter setting patch (via master beacon then 3 x TC-Level from SVL) in order to reduce the false alarm probability on LD and HD beacons • need to have two visibilities over Toulouse for Master Beacon but could be done later through the Svalbard master beacon • Instrument counter is reset, that implies the ground to board synchronisation to be performed again (through the Toulouse reference beacon) • Half a day of mission loss is expected after the Restart • In Routine, if problem occurs again, specific Operations between CLS and EUMETSAT