In order for a thermal shifted CG to cause a torque artifact, an out of level condition of the torsion pendulum's axis must be present at that particular time. A CG shift while perfectly level will not cause an anomalous torque. An out of level condition without a CG shift will not cause a torque.



Furthermore, both the moment magnitude of the thermo CG shift, and its vector relative to the "high point" of the out of level will define how the system reacts. For example, it the CG shifts directly toward the low point of the out of level, little torque will be generated. If the CG shifts in a vector 90 degrees from that low point, the maximum error effect will be seen.



Characterizing the system the way Paul March did is a reasonable step. However, it is important to understand that there were no changes in the experiment configuration, which shifted the CG, from that calibration to the testing regimen. Some lingering questions for example. Was the bar of aluminum that the cal weight was slid down present during the thrust test as well as the thermo cal? If not then the addition of this component can shift the high point to a new spot muddying the thermo calibration run. Was the thermo cal done with the torsion pendulum slid out of the chamber? How level was it outside the chamber? How level inside the chamber? How repeatable was the level. Did all locations share the same high point or did it shift to a new spot as it was slid into place?



