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

1. DOF 1 P Measurement of IMC to ISS 2ND LOOP RIN
2. DOF 1 Y Measurement of IMC to ISS 2ND LOOP RIN 
3. DOF 2 P Measurement of IMC to ISS 2ND LOOP RIN
4. DOF 2 Y Measurement of IMC to ISS 2ND LOOP RIN
5. DOF 3 P Measurement of IMC to ISS 2ND LOOP RIN
6. DOF 3 Y Measurement of IMC to ISS 2ND LOOP RIN