ESA Science & Technology - No. 67 - Fifth AOCS Checkout

The AOCS checkout took place between 11 and 13 October. All operations were commanded from the Mission Timeline. The checkout included the generation of a set of standard Avionics data dumps, a checkout of the SAS, run-down and cycling of the reaction wheels, cycling of the IMP, self-test of the Navigation Cameras and Star Tracker. Detailed analysis of the checkout data is on-going, but a quick-look check indicated nominal behaviour of all units.

SREM was kept continuously active in the background for the entire reporting period. All other instruments remained OFF.

A total of 9 New Norcia passes of 4 to 11 hours commanding were taken during the reporting period. Six of these passes were scheduled for tracking only. During the remaining three, TM/TC links were connected to the control centre. New Norcia was down for maintenance between 23 and 27 October. 11 tracking passes of 4 hours and 7 delta-DOR tracks have been taken with DSN.

At the end of the reporting period (DOY 300) Rosetta was at 285.8 million km from Earth (1.91 AU; one-way signal travel time was 15 minutes and 17 seconds). The distance to the Sun was 150.4 million km (1.0 AU).

Spacecraft

Payload
SREM remains active in the background for radiation monitoring with accumulation parameters configured for active cruise. All other instruments remained OFF during the reporting period.

Future Milestones

The Mars Swingby Phase formally started on 28 July. The phase includes the first payload Active Checkout (PC4) in November / December 2006, while the actual swingby will take place on 25 February 2007, followed by a Deep Space Manoeuvre in April 2007.

The next short-term activity is a Trajectory Correction Manoeuvre on 13 November, introduced in the flight plan during the reporting period to improve the accuracy of the Mars approach in January 2007.