No. 142 - Flyby data downlinking
03 Aug 2010 17:28
Report for the period 11 July to 30 July 2010
This report covers 20 days of Rosetta mission operations. Payload operations associated with the flyby of asteroid Lutetia were completed on 11 July and the last three weeks have been mainly dedicated to downlinking the large volume of science data acquired. All the data have now been downlinked. The spacecraft is now cruising towards the aphelion of its current orbit, which will be reached in October 2012. Work to reconstruct the relative trajectory of the flyby is continuing.
During the reporting period, mission operations were conducted using the ESA New Norcia (NNO) ground station and the DSS-24 (Goldstone, 34 metres), DSS-25 (Goldstone, 34 metres) and DSS-63 (Madrid, 70 metres) NASA Deep Space Network (DSN) antennas. The New Norcia pass on 29 July and part of the pass on 30 July were released in favour of the Venus Express mission.
At the end of the reporting period on 30 July, Rosetta was 509 million kilometres from Earth (3.4 AU); the one-way signal travel time was 28 min 18 sec (1698 sec). On 22 July, Rosetta exceeded its own previous maximum distance from Earth.
Rosetta's distance from the Sun was 427.7 million kilometres (2.85 AU). The distance to the asteroid at closest approach was 3160 kilometres. On 12 July, Rosetta captured the record for the solar-powered spacecraft that has flown furthest from the Sun, which was previously held by Stardust. This record distance will be almost doubled at aphelion in 2012 (5.29 AU).
Pre-comet science operations are now completed and the payload complement will be activated only for a final checkout before the hibernation phase. Most of these activities will be conducted in the slot allocated for December 2010 with a few exceptions required by the mission profile.
The spacecraft is now cruising towards more severe environmental conditions; for this reason, a number of test activities have been scheduled for the coming months - including a performance test of the solar arrays.
In view of the upcoming critical phase of entry into deep space hibernation, further tests have been planned in order to characterise spacecraft and ground segment behaviour under realistic RF link conditions.