ESA Rosetta Status Report 26 May 2004: Third Lander Commissioning Slot

The main activities in the reporting period were the touch-up deep-space
manoeuvre, the second Comet Linear observation and the completion of the
Lander commissioning slot 3.

The touch-up deep-space manoeuvre was executed on 16 May and very
successfully completed the trajectory targeting activities that were planned
around perihelion. Spacecraft performance for this short burn (less than 17
minutes, for a delta-V of 4.989 ms-1) was again very good, with an error of the
order of 5 mms-1.

The spacecraft +Z axis was pointed to Comet Linear on 17 May for several hours,
to allow scientific observations by ALICE and MIRO. Reports on the results of
this observation have not been finalised by the Principal Investigators yet,
however all instrument telecommands were successfully executed.

The Lander commissioning slot 3 has also been carried out very successfully,
with
achievement of all the objectives for this slot. The next Lander activation
is currently planned for the last commissioning period in Autumn 2004.

ROSINA RTOF and DFMS instrument covers were opened on 18 May in
preparation for the last commissioning slot scheduled to begin next week.

On the subsystems side the thermal environment is stable as the spacecraft is
now very close to perihelion, which will be reached on 24 May at 17:00. The
temperature of the fuel and oxidizer tanks were controlled via manual heater
switching to remain around 20 ?C in view of the isolation planned for next week.

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

At the end of the last New Norcia pass in the reporting period (DOY 142, 02:00)
Rosetta was at 35.9 million km from the Earth. The one-way signal travel time
was exactly 2 minutes.