Third Huygens checkout preliminary results good
21 December 1998The third Huygens in-flight check-out (F3) started on-board the Probe at 22:20 UTC on 21 December 1998 and was completed at 02:35 UTC, 22 December.
The check-out execution occurred, as planned, outside ground station visibility. However, a Deep Space Network station pass was scheduled to begin less than an hour later (at 03:25 UTC) and this allowed the Huygens Flight Control Team at ESOC in Darmstadt to monitor some vital Probe engineering data channelled through Cassini.
Very preliminary analysis of this data shows that all power relays are back to the nominal OFF status and that the Power Control Distribution Unit (PCDU) temperatures are decreasing at the nominal rate. An estimation of the maximum temperature reached by the PCDU during the check-out indicates that an increase of 27 to 30 degrees C has occurred: this is in line with the expected behaviour of the Probe.
The telemetry produced by the Probe during this check-out has been recorded on the Cassini Solid State Recorders and will be downlinked to ground on 28 December 1998, starting at 05:40 UTC. The data will be sent back to Earth using the Cassini High Gain Antenna , for the first time since launch.
The Huygens Flight Operations Team at ESOC and the scientific experimenters will then analyse the data. A preliminary assessment of the status of the Probe and Instruments will be published on 30 December (see link).