No. 22 - Final Preparations for Orbit Insertion
The last orbit determination performed during the reporting period has confirmed a good targeting and will be now used to produce the parameters to be commanded for the burn.
Performance of the ground segment has been nominal in the reporting period and the configuration of all critical systems for the orbit insertion is still under freeze. The spacecraft is now monitored almost 24 hours a day with the additional support of the New Norcia station and occasional tracking passes from DSN stations.
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 |
| 143 | 31/03/06 | 090 | SC monitoring |
| 144 | 01/04/06 | 091 | SC monitoring |
| 145 | 02/04/06 | 092 | SC monitoring |
| 146 | 03/04/06 | 093 | SC monitoring |
| 147 | 04/04/06 | 094 | Tanks pressurisation and start of dual station coverage |
| 148 | 05/04/06 | 095 | Helium tank warm-up |
| 149 | 06/04/06 | 096 | Switch to Short MTL |
At the end of the last Cebreros pass in the reporting period (DOY 096, 13:00) Venus Express was at 114.5 million km from the Earth, 107.3 million km from the Sun, and 2 million km from Venus. The one-way signal travel time was 382 seconds.
Payload Activities
ASPERA
The instrument is off.
MAG
The instrument is off.
PFS
The instrument is off.
SPICAV
The instrument is off.
VeRA
The USO is kept powered but muted.
VIRTIS
The instrument is off.
VMC
The instrument is off.
Ground Facilities
Cebreros is regularly used for operations and as from DoY 094 also New Norcia is used daily to track the spacecraft. The tracking time is then also augmented by tracking passes offered by the DSN network with the stations in Goldstone and Canberra. The DDOR campaign continues as foreseen.
Future Milestones
On DoY 097 the essential commands for the VOI burn will be uplinked to the spacecraft with an execution time of DoY 101 between 07:00 and 08:00 UTC. The spacecraft will be then continuously monitored for the next days till DoY 100 when the mass memory will be switched OFF and the FDIR settings will be changed for the VOI phase. These activities are not essential for the burn itself but are performed in order to minimise the risk of autonomous actions taken by the spacecraft that could hamper the execution of the burn.
With the capture burn the spacecraft will be inserted in a highly elliptical orbit around Venus with a period of about 9 days, an apocentre of about 350 000 km and a pericenter below 400 km. The first science observations of the planet will be done during this orbit together with additional changes of velocity required to control the next pericenter and to lower the apocenter altitude.
The overall phase of the orbit insertion phase will last till the beginning of May when Venus Express will finally be on the designed operational orbit.
The current nominal times for the events during Venus Orbit Insertion on Tuesday 11 April 2006 (DoY 101) are:
| Event | Spacecraft Time (UTC) |
Ground Receive Time (UTC) |
| VOI LSP start | 07:07:59 | 07:14:44 |
| VOI main engine start | 07:10:29 | 07:17:14 |
| Pericentre passage | 07:36:37 | |
| Eclipse start | 07:37:45 | |
| Occultation start | 07:38:27 | 07:45:12 |
| Occultation end | 07:48:33 | 07:55:18 |
| Eclipse end | 07:55:13 | |
| VOI burn end | 08:00:42 | 08:07:28 |
Due to the sensitivity to the predicted minimum altitude, the expected occultation start and end times may still change by up to a few seconds until the final estimates are made on Monday.