No. 186 - Quadrature Operations
The main activity during the reporting period has been the preparation of the swap from High Gain Antenna 2 (HGA2) to HGA1 and the associated 180° flip of the spacecraft around its Z-axis, planned for Monday, 8 June. The HGA swap and the attitude flip are necessary as part of the quadrature operations, because the spacecraft attitude for continuing the use of HGA2 would result in illumination of spacecraft faces not designed to cope with such exposure.
VeRa gravity observation campaign
The mission's eighth gravity observation campaign (GRA#8) was completed this week. The campaign is part of the Venus Express Radio Science Investigations (RSI) performed under the Venus Radio Science experiment (VeRa).
The GRA#8 campaign was a set of four observations, executed with the spacecraft's High Gain Antenna 2. The first three observations were covered in the previous report (No. 185). The fourth and last observation of this campaign has been performed on Sunday, 31 May. One more set of four gravity observations is now planned before 1 July 2009. It will be done after the HGA swap of 8 June and thus will make use of HGA1 - the bigger dish with a higher signal to noise ratio.
The 70m NASA DSN ground station at Canberra, Australia, was used for receiving the spacecraft's radio signals in the gravity observation campaign.
The table below shows a chronology of the main activities:
| MET (Day) |
Date | DOY | Main Activity |
| 1300 | 31/05/09 | 151 |
Canberra RSI pass (GRA#8). |
| 1301 | 01/06/09 | 152 |
Pass skipped |
| 1302 | 02/06/09 | 153 |
Communications pass over Cebreros |
| 1303 | 03/06/09 | 154 |
Pass skipped |
| 1304 | 04/06/09 | 155 |
Shortened communications pass over Cebreros |
| 1305 | 05/06/09 | 156 |
Pass skipped |
| 1306 | 06/06/09 | 157 |
Communications pass over Cebreros. |
At the end of the last Cebreros pass in the reporting period (DOY 157) Venus Express was orbiting Venus at 105.92 million km from the Earth. The one-way signal travel time was 353 seconds.
Payload Activities
ASPERA
The instrument was regularly operated as part of the routine plan.
MAG
The instrument was regularly operated as part of the routine plan.
PFS
The instrument was not operated during the reporting period.
SPICAV
The instrument was regularly operated as part of the routine plan.
VeRA
RSI measurements for gravity observation campaign #8 were carried out on 31 May.
VIRTIS
VIRTIS-M was operated in the visual channels only.
VMC
The instrument was regularly operated as part of the routine plan.
Future Milestones
- Swap of high gain antenna (HGA) from HGA2 to HGA1 on 8 June 2009.
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This report is based on the ESOC mission operations report, MOR #186. Please see the copyright section of the legal disclaimer (bottom of this page) for terms of use.