No. 54 - Successful Perilune Raising Manoeuvres
In total, the perilune raising manoeuvres required 2404 attitude segments in two weeks (this number usually lies between 180 and 240 per week) and 520 reaction wheel off-loadings were commanded in 65 orbits.
The next step will be the trim manoeuvres lasting about two days in late July to fine tune the impact time between 5:30 and 06:30 UTC on 3 September 2006, allowing optimal observations from ESO, US Kitt-peak and Hawaii.
A Spacecraft Safe Mode occurred on 15 July 2006 at 04:17:04 because the startracker stopped providing valid attitude data for more than 5000 seconds. The spacecraft was fully recovered and payload activities were restarted on the 18 July 2006. The cause of the problem is still under investigation.
The payload activities will continue during the last weeks of the mission with short interruptions for the trim manoeuvres at the end of July and just prior to the impact.
After the tracking campaign with the Chinese CLTC in June, another one is being planned with ISRO in preparation for their lunar mission. This will take place during the third week of July.
The operations with the SMART-1 Ground Operations Automation System (GOAS) are proceeding as planned with some delays due to problems with the interface of the mission control system. A real time demonstration of GOAS is planned during the second half of July before the end of the mission.
Future Activities
The future activities are focused on:
- Carry out the trim manoeuvres and continue science afterwards
- Preparation of papers for IAA in Valencia
- Preparation of mission termination and closure
Spacecraft Status
The spacecraft status is good with all functions working nominally.
AOCS
The performance of the AOCS subsystem has been nominal during most of the time in this reporting period. There were two anomalies with the startracker:
- Not possible to request startracker image. Problem was solved on 14 July
- Safe Mode because the startracker stopped providing valid attitude data for more than 5000 seconds. Spacecraft fully recovered again on 18 July
Electric Propulsion, Power, Thermal
During the reporting period, the electric propulsion system was off. The performance of the power and thermal subsystems was very good.
Orbital Information
|
SMART-1 OD453 Close to Apolune 2631 Elements WRT Moon and its equator of date | |
| Pericentre Distance (km) | 1984.625277 |
| Apocentre Distance (km) | 4939.507385 |
| Semi Major Axis (km) | 3462.066331 |
| Eccentricity | 0.426751 |
| Inclination (°) | 90.946022 |
| Ascending Node (°) | 239.683817 |
| Argument of Pericentre (°) | 223.535143 |
| True Anomaly (°) | 180.000003 |
| Osculating Orbital Period (h) | 5.077598 |
The changes in four parameters since apolune 2598 are:
- semi-major axis -0.1 km
- perilune height -50.1 km
- apolune height +49.8 km
- orbital period -0.0 minutes