31 May 2011 14:00

During the reporting period, Rosetta went through a solar opposition phase with a consequent very low level of activities. Due to the extremely large heliocentric distance, the opposition conditions did not affect the performance of the telemetry and telecommand subsystem. Further activities were performed in preparation for the deep space phase. The spacecraft is currently entering the final preparatory phase for entry into hibernation.

During the reporting period, mission operations were conducted using the ESA New Norcia (NNO) ground station.

At the end of the reporting period on 15 May, Rosetta was 508 million kilometres from Earth (3.39 AU); one-way signal travel time was 1695 seconds (28 minutes 15 seconds). The distance from the Sun was 654 million kilometres (4.37 AU). On 19 April, Rosetta was at a geocentric distance of about 492 million kilometres; the spacecraft will not be so 'close' to Earth again until the end of October 2014.

Spacecraft

Future Milestones

With the exception of a final solar array performance test, spacecraft activities preceding the hibernation phase have now been completed. Configuration for the hibernation phase will take place during the next reporting period, with a progressive deactivation of unneeded units and activation of those required for entry operations.

Summary of upcoming events:

• 20 May 2011: End of opposition phase
• 21 May 2011: Solar arrays test at 4.4 AU
• 23 May 2011: Solid-state mass memory configuration for low power conditions (one memory module); Start of power management for antenna pointing mechanism electronics /solar array drive electronics (repositioning)
• 30 May 2011: Switch on second inertial measurement package
• 31 May 2011: Power consumption characterisation test
• 01 June 2011: Low-gain antenna telecommand links test (NASA Deep Space Network Canberra and ESA New Norcia ground stations); Safe mode configuration for low power conditions (Low power flag)
• 08 June 2011: Hibernation entry

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This report is based on the ESOC mission operations report, WOR #156. Please see the copyright section of the legal disclaimer (linked from the home page http://sci.esa.int) for terms of use.