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No. 192 - Start of Earth Occultation Season #7

No. 192 - Start of Earth Occultation Season #7

Report for Period 12 July to 18 July 2009The Venus Express spacecraft and instruments performed nominally during this week. The mission's seventh season of Earth occultation experiments started on 16 July 2009.

VeRa Earth occultation season #7
The first three observations of the seventh season of Earth occultation experiments have been successfully performed during the reporting period. These experiments effectively represent a sounding of the Venusian atmosphere and ionosphere. The measurements are made just before and after the spacecraft passes behind the disk of Venus as seen from Earth (occultation).

The occultation measurements are part of the Venus Express Radio Science Investigations (RSI) performed under the Venus Radio Science experiment (VeRa). For these investigations the VeRa team makes use of the radio links of the spacecraft's communications system. The spacecraft's High Gain Antenna is pointed toward the Earth before the approach to occultation and a dual signal is sent in the S-band and X-band. Just before and after the occultation, the transmitted signal passes through the ionosphere and atmosphere of Venus. The effect that this has on the received signal gives valuable information on the composition and characteristics of the atmosphere as a function of altitude.

The 35m ESA deep space antenna at New Norcia (NNO), Australia, was used for receiving the spacecraft's radio signals on ground.

The table below shows a chronology of the main activities:

MET
(Day)
Date DOY Main Activity
1342 12/07/09 193

Communications pass over Cebreros

1343 13/07/09 194

Communications pass over Cebreros.
Pass shortened due to maintenance of the Cebreros ground station 

1344 14/07/09 195

Communications pass over Cebreros.
Pass shortened due to maintenance of the Cebreros ground station

1345 15/07/09 196

Communications pass over Cebreros

1346 16/07/09 197

Communications pass over Cebreros.
RSI occultation measurements with NNO

1347 17/07/09 198

Communications pass over Cebreros.
RSI occultation measurements with NNO

1348 18/07/09 199 Communications pass over Cebreros.
RSI occultation measurements with NNO

At the end of the last Cebreros pass in the reporting period (DOY 199) Venus Express was orbiting Venus at 154.96 million km from the Earth. The one-way signal travel time was 516 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
Three occultation experiments took place on DOY 197, 198, and 199.

VIRTIS
VIRTIS-M was operated in the visual channels only.

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


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Legal disclaimer
This report is based on the ESOC mission operations report, MOR #192. Please see the copyright section of the legal disclaimer (bottom of this page) for terms of use.

Last Update: 1 September 2019
11-Jul-2020 06:04 UT

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