Ryan S., Jason O.

Since we've been seeing slow alignment changes in the PMC over recent weeks (i.e. alog77646), Jason and I tried remotely adjusting alignment into the PMC this morning using the two picomotor-controlled mirrors with the ISS off. Unfortunately, we weren't able to get much improvement out of it, only increasing PMC transmitted power from about 108.0W to 108.1W (both readings taken with ISS on before and after our adjustments). This reinforces the hypothesis that there's some alignment drift or mode-matching change happening further upstream from the PMC, such as in the amplifiers, which would need a more in-depth procedure on-table.

While here, we also took the opportunity to improve the FSS RefCav alignment as the FSS TPD signal has been lower than we'd like. Using the two picomotor-controlled mirrors in the FSS path, we saw a much more reassuring improvement here, increasing the RefCav transmitted signal from about 815mV to 880mV. We realized after the fact that the signal here was "breathing" more than it could have been since we left the IMC locked during our adjustments.

Snapshot of the PSL quad camera images taken after our adjustments included for posterity.