Mars Express Status Report - September 2009
During this reporting period mission performance has been nominal, with an average of 1.6 science pointings and 5 observations per orbit. There were 105 orbits with pericentre passages in September, corresponding to the operations medium term plans MTP-69 and MTP-70.
|Spacecraft distance to Earth||240 million km||211 million km|
|One-way signal travel time||13m 10s||11m 45s|
|Sun elevation at pericentre||+23°||+33°|
The instruments performed nominally during the reporting period. As part of the routine operations all instruments were operated regularly: ASPERA on 100% of the orbits, HRSC on 70%, MARSIS on 75%, OMEGA on 30%, PFS on 86%, and SPICAM on 100% of the orbits. In addition 11 VMC observations have been performed. Overall, for all instruments, 99% of the planned observations were executed successfully. The daily amount of returned science data was 3.1 Gbit.
A software patch to improve the performance of the ASPERA instrument has been finalized and is now ready to be uplinked to Mars Express.
Spacecraft status and performance
On 14 September the ephemerides extension covering up to early 2011 has been loaded.
On 21 September a series of tests started with the internal mass memory of the PFS instrument. These tests were to check whether the spacecraft's overall on-board data handling (OBDH) bus usage can be increased by retarding the PFS data delivery.
Thermal and Power sub-systems
Both sub-systems are performing nominally. In preparation of the 2009-2010 eclipse/aphelion season, preliminary science plans from ESAC have been analysed and final planning guidelines agreed. Although the criticality of this forthcoming season is in-between that of the 2006 and 2008 similar seasons, an extensive set of science observations will be performed thanks to experience gained in the past and fine-tuned phasing made possible by the advanced planning.
The battery assessment estimates the capacity degradation to be at 27-33% in June 2009, to be rechecked in October before the eclipse season. The battery end-of-charge level has been brought back to 100% on 24 September to increase safety during increasing discharges due to nadir pointings.
Telemetry, Tracking & Command (TT&C)
The TT&C sub-system is performing nominally. The telemetry bit rate over 34m ground stations was increased from 114 to 152 kbps on 18 September.
Radio science investigations using the spacecraft's radio links took place 13 times per week, including 4 Bistatic Radar experiments over 70m ground station antennae. These investigations are part of the Mars Radio Science experiment (MaRS).
In collaboration with the NASA Jet Propulsion Laboratory (JPL) preparations are underway for the upcoming re-test of the Mars space relay and Earth interfaces between Mars Express orbiting Mars and the NASA Rover Spirit (MER-A) on the Martian surface.
Ground segment status and performance
Mars Express operations were supported by ground stations from the ESA tracking station network (ESTRACK) and the NASA Deep Space Network (DSN).
The number of tracks was on average 19 per week, with 30 passes over New Norcia (ESTRACK), 22 over Cebreros (ESTRACK), 4 over Madrid (DSN), and 27 over Goldstone (DSN). More than 99.9% of the data available on-board the spacecraft has been received on ground.
- 2 October 2009: SPC decision on mission extension for 2010-2012
- 10 November 2009 - 19 April 2010: The 8th eclipse season
- 3 March 2010: Phobos closest approach ever (at 62 km from the moon's centre and 50 km from its surface)
- 15 August 2010: End of the 8th occultation season (started on 20 September 2009)