No. 146 - End of solar conjunction
During the reporting period, mission operations were conducted using the ESA New Norcia (NNO) ground station and the DSS-24 (Goldstone, 34 metres), DSS-54 (Madrid, 34 metres) and DSS-65 (Madrid, 34 metres) NASA Deep Space Network (DSN) antennas.
Main activities during reporting period
|317||13-Nov-2010||Monitor + reaction wheel C relubrication|
At the end of the reporting period on 14 November, Rosetta was 655 million km from Earth (4.44 AU); the one-way signal travel time was 36 min 58 sec (2218 sec). The spacecraft's distance from the Sun was 528.6 million km (3.53 AU).
Also on 14 November, Rosetta reached its maximum distance from Earth so far (4.44 AU). Due to the movement of Earth around the Sun, the spacecraft-Earth distance will now decrease to 3.29 AU on 19 April 2011; it will increase again afterwards and break the current record at the end of July 2011.
Attitude and orbit control system
Since 27 August, reaction wheel C has been exhibiting very noisy friction torque; since its behaviour appears to be degrading, a decision was taken to perform a relubrication and operate the wheel at lower speeds (< 1000 RPM, except during slew manoeuvres). In view of this problem, the use of reaction wheels in safe mode has been disabled since 13 November.
|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. Updated on-board control procedures were uplinked to the spacecraft on 8 November (DoY 312/2010).|
|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 Hibernation Readiness Review was held on 5 November as planned. The board declared all the objectives of the review successful pending the implementation of a few recommendations and actions.
The plan for the payload checkout is as follows:
- week 47: RPC EEPROM refresh
- week 48: Lander test part one and passive checkout of payload complement
- week 49: Lander test part two and ROSINA software update
The activities scheduled for the OSIRIS instrument have been postponed until the conclusion of the relevant Material Review Board (MRB) is available. The instrument will be activated after the first rendezvous manoeuvre, at a time compatible with the spacecraft operations plan.
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.