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No. 216 - Start of Solar Conjunction Operations

No. 216 - Start of Solar Conjunction Operations

Report for Period 27 December 2009 to 2 January 2010The Venus Express spacecraft and instruments performed nominally during this week. On 29 December (DOY 363) the Venus Express operations entered the solar conjunction phase. During this phase, which will last until 22 January 2010, no science activities are planned and there are fewer, plus shorter, communication passes. All science operations were stopped on DOY362. All on-board science data was transmitted to ground and the solid state mass memory (SSMM) was emptied in preparation of the solar conjunction operations.

The table below shows a chronology of the main activities:

MET
(Day)
Date DOY Main Activity
1510 27/12/09 361

Communications pass over Cebreros

1511 28/12/09 362

Communications pass over Cebreros.
Science operations had stopped already before the pass.
Last science dumps commanded (SSMM emptied before end of pass)

1512 29/12/09 363

Start of solar conjunction operations.
Telemetry bitrate lowered to 297 bps, telecommand bitrate lowered to 250 bps.
Communications pass over Cebreros.
Short pass of 3 hours. Conjunction activities

1513 30/12/09 364

Communications pass over Cebreros.
Short pass of 3 hours. Conjunction activities

1514 31/12/09 365

Communications pass over Cebreros.
Short pass of 3 hours. Conjunction activities

1515 01/01/10 001

Communications pass over Cebreros.
Short pass of 3 hours. Conjunction activities

1516 02/01/10 002

Communications pass over Cebreros.
Short pass of 3 hours. Conjunction activities

At the end of the last Cebreros pass in the reporting period (DOY 002) Venus Express was orbiting Venus at 256 million km from the Earth. The one-way signal travel time was 853 seconds.

Spacecraft

Attitude and Orbit Control System (AOCS)
The AOCS is in its nominal configuration and performing nominally. Operations continue with all four reaction wheels. A new wheel regime was implemented on 29 December 2009 (DOY 363), as part of the solar conjunction operations. This operational phase will last till 22 January 2010.

A slight increase of the friction on reaction wheel 1 (RW1) as well as in RW1's bearing temperature is seen from DOY 363 onward. This is due to the new wheel regime.

The behaviour of RW2 remains the same as during the previous reporting periods (see status report no. 212).

Payload Activities

ASPERA
Since DOY 362 the instrument was not operated during the conjunction phase.

MAG
Since DOY 362 the instrument was not operated during the conjunction phase.

PFS
The instrument was not operated during the reporting period.

SPICAV
Since DOY 362 the instrument was not operated during the conjunction phase.

VeRa
Since DOY 362 the instrument was not operated during the conjunction phase.

VIRTIS
Since DOY 362 the instrument was not operated during the conjunction phase.

VMC
Since DOY 362 the instrument was not operated during the conjunction phase.


Future Milestones

  • Venus at superior conjunction on 11 January 2010
  • End of superior conjunction operations: 22 January 2010, after the communications pass
  • Start of routine science operations: 23 January 2010, after the communications pass


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Legal disclaimer
This report is based on the ESOC mission operations report, MOR #216. Please see the copyright section of the legal disclaimer (bottom of this page) for terms of use.

Last Update: 1 September 2019
20-Sep-2020 18:07 UT

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