395 Conclusions and Lessons Learned  

The primary lesson learned from this mission goes back to the age old saying of “test early and test often”.  Much of the issues in this program stemmed from not doing enough validation testing up front to develop a  better understanding of early concepts . A notable lesson from testing early however is that care should be  taken to understand the applicable boundary conditions of the system. Early trade studies using both  analysis and testing should be carried out with an effort to emulate the final system bou ndary conditions.  Early effort test booms in this program experienced several stress ruptures; these were eliminated by  including the long- term storage test in the development and qualification test flows. In addition, early hinge  torque tests did not incl ude the boom end fittings or even full -length booms.  It was found that the parts of  the boom outside the hinge regions, especially the proximal end fitting, change the boundary conditions of  the hinge significantly and therefore increased the hinge output torque. Without this increased torque the  hinges would not have met the torque margin requirements, but the increased torque with the end fitting  overcame the resistive torque from the electrical harness.  

Additional critical lessons learned in this progr am were based on the lack of accepted qualification methods  for high strain composite materials.  At the start of this program,  it was identified that the allowable material  properties based on existing standards would not be enough for characterizing the relevant performance  properties for thin flexible composite structures. To  qualify these structures in a relevant manor the simp le  methods described in this paper were devised to satisfy the needs of a high value new space customer.   

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