Science & Exploration

Mars Express status reports

02/07/2003 237 views 0 likes
ESA / Science & Exploration / Space Science / Mars Express

ESA’s Mars Express spacecraft is progressing further every day on its journey to the Red Planet. Everything is set for arrival at Mars on the night of 25 December 2003, after a journey of about 400 million kilometres. In the weeks since its launch, engineers have started to thoroughly test the spacecraft and its equipment.

This testing phase is standard for all spacecraft on the way to their destination. Known as commissioning, it began 3 weeks after the launch. During this time, ground controllers sent signals to each of the orbiter's seven instruments to switch them on and verify their health status. As well as commissioning the instruments, the ground controllers also tested each of the spacecraft’s subsystems. There was a thrilling moment when one of the on-board computer memory units, known as the Solid State Mass Memory (SSMM), seemed to not respond properly during the instruments check-out. Good progress has been made on this issue in the last few days: a test involving all instruments was completed successfully by recording and recovering the data through the SSMM.

Unfortunately, during the commissioning of the power subsystem, ground engineers recorded an interconnection problem between the solar arrays and the power conditioning unit on board the spacecraft. This means approximately 70% of the power generated by the solar arrays is available for the satellite and its payload to use. This anomaly has no effect on the state of the spacecraft and has no impact on the mission during the whole trip to Mars, including the orbit insertion phase once at destination.

Despite this, the experts analysing the anomaly believe that even with this power shortage, the nominal Mars observation mission will be achievable. However, satellite payload operations may have to be reviewed for certain short periods of the mission.

Ground engineers are now preparing for the last of the payload’s tests: the Beagle-2 lander will undergo its check-out on 4-5 July 2003. The experts are looking confidently to it. “In fact,” says Rudolf Schmidt, Mars Express Project Manager, “overall, the spacecraft is in good shape. We are simply getting to know its personality.”

25 June

The instruments on board ESA's mission to Mars, Mars Express, are in the process of being tested to verify that they have survived the launch successfully and will work properly. One of these tests on the Mars Express lander, Beagle 2, has been postponed to the first week of July. This will give engineers extra time to investigate a temporary anomaly that occurred in a memory unit, the so-called 'Solid State Mass Memory' (SSMM). The SSMM stores data from the instruments before sending them to Earth.

This anomaly happened last week during the test of OMEGA, one of Mars Express instruments. For a short period of time, the output of one part of the SSMM contained errors. The problem disappeared spontaneously. The affected memory unit is now working properly. To preserve the data which are stored in this part of the memory, while trying to understand why it occurred, the instrument checks have been rescheduled.

These kind of events are considered routine in a space mission, but engineers would like to understand the causes before re-starting the instrument tests.

6 June 2003
The first trajectory correction manoeuvre has been successfully completed and communications with Mission Control have been switched successfully from the low-gain antenna to the high-gain antenna.

At 07:30 CEST (5:30 UT) this morning, Mars Express was 1 million km from Earth (geocentric distance, which is from the centre of the Earth).

2 June 22:00 CEST. Launch summary
The launch of ESA's Mars Express spacecraft onboard a Russian Soyuz/Fregat launcher from the Baikonur cosmodrome took place at 19:45 Central European Summer Time (CEST). Separation of the spacecraft from the Fregat upper stage took place 1 hour 32 minutes after liftoff at 21:17 CEST. First signals of the satellite received: 21:45 via New Norcia ground station in Western Australia. By 21:58 both solar arrays had successfully been deployed. The spacecraft is on its way to Mars and telemetry confirms a nominal satellite performance in all subsystems.

21:58 CEST. Both solar arrays deployed.

21:45 CEST. First signals received via New Norcia ground station.

21:17 CEST. Separation successfully completed

19:45 CEST. Lift off of Soyuz and Mars Express.

19:40 CEST. Operations Director reports go for launch.

18:00 CEST. NNO tracking tests have started

16:15 CEST. The go-ahead has been given for launcher filling, and fuelling has commenced.

29 May 2003
The State Commission has given the green light for rollout. Rollout has been completed and the launcher and spacecraft are in the vertical position on the launch pad.