No. 53 - Ongoing Push-broom Operations
26 Jun 2006 12:05Report for Period 15 May to 18 June 2006
The work during this reporting period has been focused on continuation of push-broom operations and the preparation of the manoeuvres as part of the SMART-1 operations during the last months of the mission until Moon impact. Pushbroom operations have continued during the entire reporting period. The last pushbroom pointing finished on 16 June.
To ensure that the lunar impact will be observable from the Earth, SMART-1's orbit will be boosted, raising the perilune distance by ~90 km. This shifts the point of impact to the Moon's near side, where impact is planned to occur on 3 September 2006.
The manoeuvre strategy consists of a series of reaction-wheel off-loadings combined with about three hours of intermittent thrust centred at apolune during 74 orbits. The asymmetric firing of the attitude thrusters will produce a small velocity variation aligned with the flight direction that will change the orbit by an accumulative effect.
Moon impact preparation:
The 35° solar array offset, implemented to reduce the array's overheating, was removed after passing the peak in the temperature evolution. The solar arrays were back to original mechanical offset angles on DoY 164 at 15:30:00UTC, resulting in an increase again in temperature of about 8 °C, but within the operational limits.
All SMART-1 subsystems are nominal and are expected to continue functioning properly until the Moon impact. There will be operational thermal constraints for both the platform (specially the startrackers) and the payload at low Moon altitudes. The first will be overcome controlling the attitude to maintain at least one star tracker operational all times. The payload instruments constraints al low altitudes will be controlled by the Science and Technology Operations Centre.
The Operations Automation system has been used operationally for the first time on DoY 138. Some anomalies have been observed which are being resolved prior to full operational use.
The Next future activities are focused on the following:
The spacecraft status is good with all functions working nominally.
Electric Propulsion, Power and Thermal
The changes in four parameters since apolune 2498 are: