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No. 145 - Superior solar conjunction

No. 145 - Superior solar conjunction

Report for the period 25 September to 22 October 2010This report covers 28 days of Rosetta mission operations. During the reporting period, the spacecraft has been going through a superior solar conjunction, which will end on 31 October. During this phase, the spacecraft was configured in active cruise mode, but with very limited ground station communications due to the effects of the Sun on the RF signal transmission. The NASA Deep Space Network (DSN) provided additional support to the radio science investigations during this phase.

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

DoY Date Pass Activity
270 27-Sep-2010 NNO 2407 Monitor
273 30-Sep-2010 NNO 2410 Monitor
275 2-Oct-2010 DSS-54 2412 Monitor
276 3-Oct-2010 DSS-54 2413 Monitor
277 4-Oct-2010 DSS-65 2414
NNO 2414
Monitor
278 5-Oct-2010 DSS-15 2415 Monitor
279 6-Oct-2010 DSS-65 2416 Monitor
280 7-Oct-2010 DSS-54 2417
NNO 2417
Monitor
281 8-Oct-2010 DSS-65 2418 Monitor
282 9-Oct-2010 DSS-65 2419 Monitor
283 10-Oct-2010 DSS-63 2420 Monitor
284 11-Oct-2010 DSS-63 2421
NNO 2421
Monitor
285 12-Oct-2010 DSS-63 2422 Monitor
287 14-Oct-2010 DSS-63 2424
NNO 2424
Monitor
288 15-Oct-2010 DSS-63 2425 Monitor
289 16-Oct-2010 DSS-63 2426 Monitor
290 17-Oct-2010 DSS-63 2427 Monitor
291 18-Oct-2010 DSS-63 2428
NNO 2428
Monitor
292 19-Oct-2010 DSS-63 2429 Monitor
294 21-Oct-2010 NNO 2431 Monitor
295 22-Oct-2010 DSS-63 2432 Monitor

DoY = Day of year

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).

Spacecraft

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.

Payload Status
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).

Future milestones

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.

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Legal disclaimer
This report is based on the ESOC mission operations report, WOR #145.  Please see the copyright section of the legal disclaimer (linked from the home page http://sci.esa.int) for terms of use.

Last Update: 1 September 2019
20-Sep-2020 17:47 UT

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