No. 19 - Final Venus Approach Phase
21 Mar 2006 09:31Report for period 10 March to 16 March 2006
The reporting period has marked the start of the final Venus approach phase. All activites will now focus on the navigation and preparation for the Venus Orbit Insertion operations.
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:
At the end of the last Cebreros pass in the reporting period (DOY 075 13:00) Venus Express was 83 million km from the Earth, 105.4 million km from the Sun, and 10.1 million km from Venus. The one-way signal travel time was 278 seconds.
In December 2005, during the first planned activation of the instruments, various calibration activities showed that the instrument sensor is working perfectly, but revealed that the instrument scanner is stuck in its closed position, inside the instrument box.
Several attempts to move it were made at the time, but the instrument did not respond. Experts then initiated a number of ground tests with a spare model of the scanner, and suspected a thermal problem by which low temperatures were blocking the rotation of the mechanism.
Another attempt to move the scanner was made on 16 March 2006, in warmer flight conditions. Unfortunately, the scanner remains stuck.
The next opportunity to perform another test on the spacecraft will be end of April, after the Venus Orbit Insertion. In the mean time, PFS will remain switched off with the scanner in a safe closed position.
The spacecraft is now configured for the Venus approach phase and activities will focus only on this.
The intense navigation campaign is currently at a period of maximum activity in order to have an extremely precise assessment of the spacecraft trajectory versus its target point at the planet.
During the next reporting period the spacecraft will reach its perihelion (which is inside the Venus orbit around the Sun). The trajectory will then cross the orbital path of Venus on 11 April - when the orbit insertion manoeuvre will take place.