No. 91 - Trajectory Correction for Asteroid Steins Flyby
03 December 2007 10:31Report for Period 17 November to 30 November 2007
After Rosetta's Earth swing-by of 13 November operations focused on science data downlink, spacecraft reconfiguration and check-out activities, and on the correction of the spacecraft's trajectory.
A total of 12 New Norcia passes were taken during this reporting period. The tracking campaign with the Deep Space Network (DSN) stations was completed on DoY 329. Some of the passes between 19 and 25 November have been used for TM/TC activities as well.
At the end of the reporting period (DoY 334) Rosetta was at 13.1 million km from Earth (0.088 AU) and the one-way signal travel time was 44 seconds. The distance to the Sun was 139.5 million km (0.93 AU).
Trajectory Correction Manoeuvre
A trajectory correction manoeuvre was executed on 23 November, 00.54 UT, in order to set the proper trajectory for the close encounter with asteroid Steins planned for September 2008. The manoeuvre was executed using accelerometers, and lasted 538 seconds (the time that Rosetta was in Orbit Correction Mode). The commanded Delta-V was 1.5269 ms-1 and the executed Delta-V (as read in spacecraft telemetry) was 1.526107
The second leg of this correction manoeuvre will be executed in February 2008.
The Earth swing-by phase is now completed and the spacecraft will enter a quiet period. During the next reporting period some tests with the navigation cameras will be performed to prepare for the optical navigation campaign required for the asteroid Steins approach phase next year. The relatively quiet period will also be taken as an opportunity to characterise the solar torques on the spacecraft and some recovery activities on the MIDAS instrument.