No. 165 - Quadrature Operations
VIRTIS continues to be operated in the visual channels only. A test with the redundant VIRTIS unit was executed on 10 January.
DDOR
On 9 January delta differential one-way ranging (DDOR) was performed using the New Norcia and Cebreros ground stations to track the spacecraft. These measurements are performed monthly to support the accurate determination of the ephemeris for the planet Venus that is maintained by NASA's Solar System Dynamics Group.
The DDOR measurement principle uses a technique to highly accurately determine the position of a transmitter in space and relies on observing the time delay between reception of the signal from the transmitter by two ground stations at different positions on Earth. In this case the Venus Express spacecraft is the transmitter and the two ground stations are New Norcia in western Australia and Cebreros in Avila, Spain.
The table below shows a chronology of the main activities:
| MET (Day) | Date | DOY | Main Activity |
| 1153 | 04/01/09 | 004 |
Skipped communications pass over Cebreros |
| 1154 | 05/01/09 | 005 |
Communications pass over Cebreros |
| 1155 | 06/01/09 | 006 |
Skipped communications pass over Cebreros |
| 1156 | 07/01/09 | 007 |
Communications pass over Cebreros |
| 1157 | 08/01/09 | 008 |
Skipped communications pass over Cebreros. |
| 1158 | 09/01/09 | 009 |
Communications pass over Cebreros. |
| 1159 | 10/01/09 | 010 |
Skipped communications pass over Cebreros |
At the end of the last Cebreros pass in the reporting period (DOY 010) Venus Express was orbiting Venus at 107.4 million km from the Earth. The one-way signal travel time was 358 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
No measurements were taken during the reporting period.
VIRTIS
The instrument was regularly operated as part of the routine plan. VIRTIS is operated in the visual channels only.
A test to operate the M cooler from the redundant electronic units of VIRTIS was executed and the data are under analysis.
VMC
The instrument was regularly operated as part of the routine plan.
Future Milestones
- High gain antenna swap from HGA1 to HGA2 on 13 January 2009.
- The quadrature phase will end on 25 January 2009.
- Commissioning of the Reaction Control Subsystem B on 12 February 2009.
- Battery Deep Discharge Test is planned for 22 April 2009.
- Start of next (outbound) quadrature phase on 29 May 2009.
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This report is based on the ESOC mission operations report, MOR #165. Please see the copyright section of the legal disclaimer (bottom of this page) for terms of use.