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No. 186 - Quadrature Operations

No. 186 - Quadrature Operations

Report for Period 31 May to 6 June 2009The Venus Express spacecraft and instruments performed nominally during this week of quadrature operations. The spacecraft entered the current quadrature phase on 29 May. These phases occur regularly and are defined by the periods in the orbit of the planet Venus during which the Sun-spacecraft-Earth angle is between 75° and 95°.

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:

Date DOY Main Activity
1300 31/05/09 151

Canberra RSI pass (GRA#8).
Communications pass over Cebreros

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.
Upload of commands for HGA swap on 8 June.
Telemetry bit rate changed from 38 kbps to 28 kbps

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

The instrument was regularly operated as part of the routine plan.

The instrument was regularly operated as part of the routine plan.

The instrument was not operated during the reporting period.

The instrument was regularly operated as part of the routine plan.

RSI measurements for gravity observation campaign #8 were carried out on 31 May.

VIRTIS-M was operated in the visual channels only.

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.

Legal disclaimer
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.

Last Update: 1 September 2019
18-Jul-2024 15:22 UT

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