()=(1 +(−)) (1)  Which could be applied as follows:  ()=					 =					 (120	) =		 ℎ					 ( = 0.0039°) =						 =		 (20 °) Giving the impedance-driven relationship for our experiment:  =+()  = 20 +()  .(2)  This simple relationship between the coil temperature and impedance altered our test ideologies. The team  now had a method of instantaneously measuring the coils temperatures at vacuum and could relate a max  coil temperature to an ambient environment to determine operational ranges. The team conducted a new  TVAC test aimed to determine the operation range for these motors in their new thermally-optimized design.  The test ran each motor in vacuum for 15 minutes to achieve steady state. The motors were then powered  off and the coil impedances were measure immediately after shutdown. The data was recorded and used  to determine a max coil temperature at a given chamber ambient temperature.   The data was coarse, and even a few seconds of delay between shutdown and measurement would result  in 10°C temperature drops (the coils are less than 1 gram each). The chamber was then heated up from   -50°C by 5°C increments until the coils reached their maximum survival temperature. The data showed a striking trend, providing the test data needed to determine the thermal design was sufficient and the AMT operation range was well-founded. The chart in Figure 11 shows the temperature data collected from the AMT X and Y-axis motors, each having two coils, notated as “A” and “B”. The four data sets were plotted against the chamber temperature and the tests concluded when the hottest coil measurement crossed the maximum coil survival temperature of 130°C. Conclusion  After a lengthy design trade, a 6-mm stepper motor from Faulhaber (FDM0620) was selected for the EDU  design. (If interested in more details from the design trade, please reference “Development of a High  Performance, Low Profile Translation Table with Wire Feedthrough for a Deep Space CubeSat” from the  43rd Aerospace Mechanisms Symposium). These motors were the smallest available anywhere on the  FY2015 market and were manufactured from a reputable vendor with flight heritage. Motors from this twophase, PRECIstep® family had flown and were planning to fly on multiple NASA missions, including another  6U CubeSat manifested on SLS EM-1. Knowing this, it was assumed that the motors would operate in a  vacuum environment once integrated into the AMT.   After a year of failure investigations and redesigns, the motors performed in vacuum within the operational  temperature ranges determined by our thermal design during thermal vacuum tests. The lessons learned  have been captured at the project level through engineering review board documentation. There is a  miniscule market for flight-qualified stepper motors in mNm torque magnitudes. If small motors like these  are required to meet mass, power, and volume budgets in vacuum, a thorough investigation and test plan  should be implemented to validate their application.   The project could have saved considerable time and cost by budgeting a few thousand dollars to purchase  a small vacuum chamber and test as often as needed, rather than invest months of labor and facility costs  to purchase multiple high-fidelity tests. Small vacuum chambers with the data output required to thoroughly  NASA/CP—2018-219887 291