M. Todd
Summary
This morning I used the early maintenance day to come in and make some measurements of IMC DOF Transfer Functions to ISS Second Loop RIN. I started by doing some OPS/GRD settings as I was here about an hour before the operator was set to come in.
I got through the first DOF measurement (DOF_1_P) without any hiccups; however a 7.0 earthquake from Philippines came in an unlocked us. Fortunately, I did not have to wait long for the IMC to relock and I proceeded with the other measurements.
DOF 1 and DOF 2 are relatively robust, but upon starting the DOF 3 measurement I had to lower the gain even more than anticipated, as the 1 and 3 Hz resonances are quite strong. The first run at this unlocked the IMC. After clearing the IMC DOF 3 P history, I let the IMC relock (it was having trouble) and continued with the subdued measurements.
I also tried to measure the UGF of each DOF loop, but was nervous about injecting that hard at the frequencies I suspected would contain the UGF.
Later, I will post a comment that tries to map the quiet time IMC contributions to the ISS Outer RIN in the regions we have enough coherence.
List of Figures
I'm adding a plot of projections of the quiescent noise in each IMC DOF loop to the ISS second loop. Note, I've cut off the TFs above 3 Hz due to coherence loss.
