I was working on alignment of the IMC, and the PSL just tripped off.
I was just hanging out in the control room trying to close the WFS loops, not out in the LVEA.
Of note, TVo and I were unable a few hours ago to close the ISS first loop. The ISS would oscillate any time we tried to close the loop. Rick (on site for the Saturday tour) was planning to help us out once the tours are over, so for now I just have the ISS autolocker off.
The laser tripped because the injection locking lost lock. The laser came back without any problems. I did notice that the laser power was down somewhat from what I remember the laser power to be from yesterday. I adjusted the temperatures of all 4 diode boxes to get more laser power instead of increasing the diode current. ILS3.png suggests that the injection locking lost lock when the input modecleaner was not swinging. Looking at ILS4.png, it looks like the laser frequency was oscillating for some time. My guess is that at some stage the FSS lost lock, which in turned pulled the master laser frequency beyond the range of the injection locking. That in turn caused the oscillator to lose lock to the master laser.