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No. 21 - Targeting for Venus Orbit Insertion

No. 21 - Targeting for Venus Orbit Insertion

Report for period 24 March to 30 March 2006The Venus approach phase is proceeding according to plan with all activities conducted successfully.

A Trajectory Correction Manoeuvre of about 13 cm s-1 has been executed in the evening of 29 March to reduce the pericenter altitude at Venus arrival by a bit more than 100 kilometres. The latest calibration of the nominal TCM gives the following results (uncertainties are 1-sigma):

  • magnitude error = -1.2 mm/s (-0.9% +/- 2.1%)
  • direction error = 0.8 deg +/- 0.3 deg
The final calibration will be made on 3 April. The current orbit determination does not show the need for any further trajectory correction.

Performance of the ground segment has been nominal in the reporting period and the configuration of all critical systems for the orbit insertion is now under "freeze".

DDOR measurements with ESA and DSN ground stations are continuously conducted.

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

MET (Day) Date DOY Main Activity
136 24/03/06 083 SC monitoring and S-TX2 Switch ON
137 25/03/06 084 SC monitoring
138 26/03/06 085 SC monitoring
139 27/03/06 086 SC monitoring
140 28/03/06 087 SC monitoring and possibly last WOL before VOI
141 29/03/06 088 Trajectory Correction Manoeuvre
142 30/03/06 089 SC monitoring

At the end of the last Cebreros pass in the reporting period (DOY 089, 13:00) Venus Express was at 104 million km from the Earth, 105.9 million km from the Sun, and 4.8 million km from Venus. The one-way signal travel time was 347 seconds.

Payload Activities

The instrument is off.

The instrument is off.

The instrument is off.

The instrument is off.

The USO is kept powered but muted.

The instrument is off.

The instrument is off.

Special Events

The Cebreros pass of DoY 089 has been fully conducted with automated operations as scheduled by the Station Computer (STC) based on input from the Venus Express Mission Planning System. Operations included ground station configuration for Venus Express, TM reception, uplink sweep, Doppler and Ranging measurements, and end of pass activities. This is a first for the ESA deep space missions and stations. It will hopefully constitute the first of a long series.

Future Milestones

Next week, operations for the Venus capture manoeuvre will begin and as from DoY 094 a dual station coverage will be guaranteed by the ESA deep space network. This coverage will be augmented by tracking passes with DSN stations.

At the end of next reporting period, DoY 096, the commands for the capture burn will be finalised and prepared for uplink the day after.

An opportunity for a Trajectory Correction Manoeuvre is foreseen on DoY 095 but it is very unlikely that it will be used.

The current nominal times for the events during Venus Orbit Insertion on Tuesday 11 April 2006 (DoY 101) are:

Event Spacecraft Time
Ground Receive
Time (UTC)
VOI LSP start 07:08:16 07:15:01
VOI main engine start 07:10:46 07:17:31
Pericentre passage 07:36:37
Eclipse start 07:37:53
Occultation start 07:38:37 07:45:23
Occultation end 07:48:25 07:55:10
Eclipse end 07:55:13
VOI burn end 08:00:39 08:07:25

Last Update: 1 September 2019
15-Apr-2024 12:17 UT

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