No. 18 - Testing Availability of MGA-S Antenna
28 June 2004 14:15Report for Week 18 to 25 June 2004
The reporting period covers the third week of Cruise 1. The main activity was a first check for availability of the MGA-S antenna, in order to select it in case of Survival Mode.
The test, executed on 20 June, had to be carried out with the 70m dish of DSN due to the orbital geometry and the attitude constraints of the spacecraft, which put the MGA in a very marginal condition from a link budget point of view. The test successfully confirmed the availability of MGA-S, and the antenna was then selected in the on-board software on 24 June for use in case of Survival Mode triggering.
In support of the investigations on the Star Tracker acquisition behaviour identified last week after having enabled the "dust settings" (see report no. 17) a test has been proposed on the spacecraft and planned for 3 July. To prepare for this test, Star Tracker B has been patched to the dust settings on 24 June and put into tracking mode.
As planned, on 24 June the GSEP pointing bias has been reset to 60 degrees above +X.
Three New Norcia ground station passes were skipped, as planned, on 19, 22 and 23 June. On 18 June a short TM monitoring pass was taken only to check correct entry into GSEP.
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 177) Rosetta was at 57.1 million kilometres from the Earth. The one-way signal travel time was 3 minutes 10 seconds.