- Life test not done in vacuum:  This remained a contested item throughout the development with ever  reoccurring questions at reviews, particularly concerning lube issues and heat dissipation. There were just simply not enough resources to do a full-simulated life test, lasting 18 months, in vacuum: Heat dissipation concerns could be settled by doing the necessary analytical work. The lube issues were partially resolved by scientific evidence, partially by pointing to similar devices that used the same  lubricant and successfully operated in space. - Joint testing not done with a flight-like controller : In today’s short development cycles, there often is not  enough time to develop long lead components in time for integrated testing: A duplicate flight-like  controller was not available for the life test, nor was a flight-like controller ready in time for the qual/acceptance testing of the joint drives. For all joint stand-alone testing, an off the shelf, 2-phase pulse  with modulated (PWM) stepper motor controller, emitting square wave signals, was used. The flight controller uses micro stepping instead. It was determined only during integrated instrument testing that the motor produced substantially less  torque than anticipated with the micro stepper controller. This jeopardized much of the previous  qualification and acceptance testing. Re-testing was not possible on the integrated instrument and renewed joint stand-alone testing was impossible due to time constraints. In particular, the input waveform generated by the flight controller was insufficiently measured, analyzed, or understood.  To compensate for the reduced torque, an in-flight remedy was implemented, increasing the in-flight  minimum temperature for the elevation actuator to 15°C. This keeps the viscosity of the actuator’s lube  lower, offsetting the decrease in torque with the micro stepper controller. Fortunately, enough heaters and additional heating power could be made available. What remained unsettled, however, was that the actual torque the motor produces with the micro stepper driver was not well known, nor was the effect of using different electrical motor inputs sufficiently well understood and evaluated.  One position error occurred during a routine aliveness test in spacecraft assembly and testing. It was  unfortunately not detected until a review of the telemetry a few days later. A visual inspection of the  instrument revealed no issues. The instrument performed as expected and all other telemetry was as  expected. Due to limited resources and time, no further investigation was performed at that time, although  instrument scanning was monitored for a repeat occurrence (none occurred prior to launch). The obvious ‘lesson learned’ here is to allow enough time for adequate overall system testing and to have  spare resources. The follow-on Diviner development proved that this is difficult. Schedule slips and late delivery of components again required substituting flight components with dissimilar engineering model (EM) components, causing the overall end-to-end system testing to be shortened as well. Table 1: Life Test Joint vs. Space Operations  - Differences between life test and space environment:  Table 1 lists the differences between the life test  and the actual in-flight conditions for all MCS joint drives. In summary, the load inertia was close to the value for the azimuth joint, but the 3.5M load cycles reflect the life of the elevation drive. With the life  tested joint surviving 3.5M cycles at a torque level equal to twice the value the elevation drive requires,  and by using a square wave controller that produces much larger dynamic load spikes (hammering  277