Current status of the Suzaku pointing error

Since launch, the 3-axis attitude control using the Inertial Reference Unit (IRU) had been done with the combination of IRU-X/Z/S1. Recently, the output of the IRU-S1 had become noisy. We then switched over from the IRU-S1 to S2 at 03: 21 on 18th, December 2009. Since the switch, it was found that the accuracy of the attitude control and determination along the DET-X axis became worse than previous by roughly a factor of two, though it has been different from observation to observation. At June 15th, 2010, the other IRU-Y was activated not for the attitude control but for the determination. The activation recovers the pointing determination accuracy down to the level before the IRU-S1 was switched off.