No. 36 - Earth Fly-by Approaches
28 February 2005 09:49Report for the period 14 to 24 February 2005
The main activity of the reporting period was the last trajectory correction manoeuvre before Earth swing-by. The manoeuvre was executed successfully on 17 February and has put the spacecraft onto its final course to Earth. Thanks to the precision of the manoeuvre execution it was not necessary to use the back-up manoeuvre slot planned for 24 February.
The first Earth swing-by will take place on 4 March 2005 at around 22h10 UT, when the spacecraft will be 1900 km from the surface. Rosetta will approach from the direction away from the Sun and have its closest approach on the illuminated side of the Earth. As the spacecraft approaches, it will seem to fly to the west and will disappear on the dayside of the Earth.
Preparation activities for the Earth swing-by included two simulations scheduled to train the team into contingency operations with the special spacecraft configuration around closest approach. Validation activities of the whole scenario, and in particular of the Asteroid Flyby Mode test with the Moon, planned for 5 March, continued using the EQM, the Simulator and involved some simulation runs on the Rosace tool by Astrium at Toulouse. A Go for AFM Test with the Moon was decided in a readiness meeting on 22 February.
The frequency of New Norcia passes is now almost daily, in support of the orbit manoeuvres and to increase tracking data recovery for precise orbit determination. For the same reason, as from 14 February daily DSN passes are taken (typically 4 hours each).
The table below shows a chronology of the main activities in the reporting period (only active passes shown):
At the end of the last New Norcia pass in the reporting period (DOY 056) Rosetta was at 2.76 million km from the Earth. The one-way signal travel time was 9.2 seconds.