No. 68 - Trajectory Correction Manoeuvre
21 November 2006 09:53Report for Period 27 October to 17 November 2006
The reporting period covers three weeks of active cruise. The activities carried out during the reporting period included a Trajectory Correction Manoeuvre and preparation for the upcoming Active Checkout (PC4).
A Trajectory Correction Manoeuvre took place on 13 November. This manoeuvre of a magnitude of 9.9 cms-1 was performed to improve the accuracy of the Mars approach in January 2007. Flight Dynamics estimated that the manoeuvre performed well (estimated overperformance of 2%).
During each weekly pass of the reporting period, Active Checkout preparation activities took place. This includes mainly uplink of Software update products to the SSMM and reconfiguration of SSMM files to support the planned operations. Finally on 15 November, the first Active Checkout Mission Timeline was loaded on-board. The campaign starts on 22 November with an RSI checkout, while checkout of the other instruments starts on 23 November.
SREM was kept continuously active in the background for the entire reporting period. All other instruments remained OFF.
A total of 6 New Norcia passes of 4 to 11.3 hours commanding were taken during the reporting period, one of which for tracking only. In addition one Delta-DOR measurement was performed with the New Norcia/Cebreros baseline. Eight tracking passes of 4 hours and one delta-DOR track have been taken with DSN.
At the end of the reporting period (DOY 321) Rosetta was at 292.6 million km from Earth (1.96 AU; one-way signal travel time was 15 minutes 41 seconds). The distance to the Sun was 157.4 million km (1.05 AU).
Trajectory Correction Manoeuvre Details
As part of the manoeuvre preparation, the accelerometer biases were calibrated. Before and after the manoeuvre, the HGA was flipped-over, resulting in a short interruption of contact. The manoeuvre performed well. Based on the tracking data acquired during and after the manoeuvre, Flight Dynamics estimated an over-performance of the order of 2%.
The Mars Swingby Phase formally started on 28 July. The actual swingby will take place on 25 February 2007, followed by a Deep Space Manoeuvre in April 2007.
The next short-term activity is the first Payload Active Checkout (PC4) starting on 23 November. The first set of time-tagged commands for Active Checkout (PC4 MTL1) was uplinked on 15 November. The first pass for this intense combined payload operations campaign is scheduled on 27 November. The campaign will last four weeks, with the last operations finishing on 22 December.