No. 55 - Spacecraft Maintenance
20 February 2006 13:51Report for Period 27 January - 17 February 2006
The reporting period covers three weeks of passive cruise, during which important maintenance activities and a test with the RPC instrument were carried out.
System autonomy updates were carried out on 2 February, when some on-board monitoring items were modified, to allow a call of the new payload emergency off OBCPs for Osiris and MIDAS loaded in earlier passes, and the addition of a new monitoring item to trigger in case of STR Reset. On 9 February, the System Init Table was modified to include commands to re-enable autonomous wheel off-loading in case of safe mode. Also on 9 February one of the OBCPs controlling the navigation Camera was updated and tested on Camera B.
A total of 3 New Norcia passes were taken over the reporting period.
At the end of the reporting period (DOY 048) Rosetta was at 388.5 million km from the Earth (2.60 AU; one-way signal travel time was 21m 35s). The distance to the Sun was 255.3 million km (1.71 AU).
An RPC-ICA troubleshooting test will be carried out on 23 and 24 February over New Norcia.
The third RSI Passive Checkout and the periodic AOCS checkout will be carried out on 2 and 3 March, followed by the Passive Checkout 2 of the rest of the payload between 3 and 7 March. Data from the checkout will be downlinked over New Norcia a few days later.
A previously unplanned scientific observation of asteroid Steins using the OSIRIS camera will be carried out in the period 11 - 12 March outside coverage. This exceptional scientific operation was agreed due to its mission relevance, as it will contribute to the knowledge base on asteroid Steins characteristics. This asteroid will be visited by Rosetta in close fly-by in September 2008.
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 of April.
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.