The spacecraft is now in its 187th orbit, in good status and with all functions performing nominally. In order to fine tune the altitude of the apogee point, required to minimise the length of the eclipses due to occur in March, the ion drive is currently being used only when the spacecraft is around perigee. This strategy will last until the end of January.
Starting from early February the ion engine will not be used to generate thrust for a period of three weeks. This phase of the mission will be used to perform the scientific instrument commissioning. A series of observations of celestial targets with different instruments is being prepared and will be described in a future report.
Another milestone was reached this week: the mission commissioning results review was held at ESOC. This review was planned to be held as soon as the first mission phase, the exit of the radiation belts, was completed.
The results of the on-orbit verification of all the spacecraft subsystems were presented. All the subsystems have now been verified. However, some spacecraft functions have yet to be tested. This is because some are triggered by a failure scenario and others have not yet been needed.
A plan has been prepared to solve the few anomalies that are still affecting the spacecraft’s smooth operations.
These include a software function to autonomously re-start the electric propulsion engine after an unexpected shutdown, a proper strategy to improve the performance of the star tracker that is affected by the combined effects of high temperature and radiation induced degradation, and a proper strategy to circumvent the occasional failures of the telemetry Reed-Solomon coding checksum.
