02 Jan 2008 12:00

The Radio Science Dual band ranging in NNO has failed during this week. The reason is the drop in the S-band signal present in the HGA1 antenna. A fine tuning of the configuration is being attempted in order to optimise the setting.

The table below shows a chronology of the main activities in the reporting period:

At the end of the last Cebreros pass in the reporting period (DOY 363, 12:00z) Venus Express was orbiting Venus at 169.6 million km from the Earth. The one-way signal travel time was 565 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 RSI activities took place this week.

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

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

Ground Facilities

New Norcia support of radio science
NNO was used in two occasions for Radio Science dual ranging. The activity failed on both occasions on 27 & 29 December 2007. The reason is understood to be due to the signal drop observed in the S-band link.

The current ranging standard does not permit different integration times for different bands. The problem is the relatively high signal-to-noise ratio in X-band with respect to S-band making it challenging to optimise integration time. This needs to be short enough to avoid saturation in X-band and long enough to allow tone lock in S-band. New configurations setting will be tried in the next reporting period.

Future Milestones

• NNO and Cebreros scheduling for 2008