No. 145 - Superior solar conjunction
During the reporting period, mission operations were conducted using the ESA New Norcia (NNO) ground station and the DSS-15 (Goldstone, 34 metres), DSS-54 (Madrid, 34 metres), DSS-63 (Madrid, 70 metres) and DSS-65 (Madrid, 34 metres) NASA Deep Space Network (DSN) antennas.
Main activities during reporting period
At the end of the reporting period on 22 October, Rosetta was 657 million km from Earth (4.39 AU); the one-way signal travel time was 36 min 32 sec (2192 sec). The spacecraft’s distance from the Sun was 509 million km (3.4 AU).
Attitude and orbit control system
The spacecraft has been using three reaction wheels for attitude control since 15 July, when reaction wheel B was switched off to conserve power; nominally, it will not be restarted until after the end of deep-space hibernation. Since 27 August, reaction wheel C has been exhibiting very noisy friction torque; its behaviour appears to be degrading and is being carefully monitored.
|ALICE||The instrument is currently OFF|
|CONSERT||The instrument is currently OFF|
|COSIMA||The instrument is currently OFF|
|GIADA||The instrument is currently OFF|
|MIDAS||The instrument is currently OFF|
|MIRO||The instrument is currently OFF|
|OSIRIS||The instrument is currently OFF|
|ROSINA||The instrument is currently OFF|
|RPC||The instrument is currently OFF|
|RSI||The USO is ON/muted since 3 February 2010 (DoY 032/2010). Experiment activities are being supported by means of dedicated ground station measurements.|
|VIRTIS||The instrument is currently OFF|
|Lander (Philae)||The instrument is currently OFF|
|SREM||The instrument is ON with standard settings since 3 February 2010 (DoY 032/2010).|
The angular separation between the spacecraft and the Sun is now slowly increasing, reducing the negative effect on RF communications. The dumping of mass memory will be resumed at the beginning of the next reporting period and the conjunction phase will formally end on 31 October.
After this phase, spacecraft activities will focus on the last payload checkout and the preparation of the instruments for the hibernation phase. These activities will be conducted between mid-November and mid-December.
The first rendezvous manoeuvre is planned for the second half of January 2011, with the first burn leg on 17 January. Due to its magnitude, this manoeuvre has been split into five nominal burns plus an optional extra one in the event that a final correction is needed.