Rosetta Status Report 9 December 2005 – 6 January 2006

Report for Period 9 December 2005 – 6 January 2006

The reporting period covers four weeks of passive cruise, with monitoring and minor maintenance activities.

On the subsystems side, the attitude guidance has been changed to +X Earth pointing on 14 December 2005, to reduce the disturbance torques experienced by the spacecraft and therefore the fuel consumption for reaction wheel offloading.

On 22 December 2005 the spacecraft was configured to sustain a non-coverage period of 14 days. This involved reducing the Housekeeping TM generation rate and extending the TC Link Timeout to 16 days. After the long non-coverage period, on 5 January 2006, the spacecraft status was nominal. The TM generation mode was changed back to the nominal one foreseen for weekly passes.

A total of 3 New Norcia passes were taken over the reporting period.

NNO Date DOY Main Activity Pass

• 665 15.12.05 349 Verify guidance change & RPC IES test
• 662 22.12.05 356 Monitor: change TC Link T/O and TM mode
• 676 05.01.06 005 SSMM files updates & TM mode back to weekly

At the end of the reporting period (DOY 006) Rosetta was at 360 million km from the Earth (2.40 AU; one-way signal travel time was 20m 00 s). The distance to Sun was 262 million Km (1.75 AU).

Future Milestones

Preparation for the first Solar Conjunction continues. The spacecraft will be at an angular distance from the Sun below 5 degrees between mid March and mid May 2006, with a minimum separation angle of about 0.3 degrees on the 13 April.

Just before the start of the Solar Conjunction the third Payload Passive Checkout (PC2) will take place in March 2006.

After the Solar Conjunction the spacecraft will be configured into Near Sun Hibernation Mode for a period of about 2 months, from end May to end July 2006.

Operations for the Mars swing-by (February 2007) will start in August 2006, with another payload passive checkout (PC3), an intense tracking campaign around the Trajectory Correction Manoeuvre (DSM-2) in September, and the first payload Active Checkout (PC4) in November/December.