438 compression load through the CDPR  for full coverage.  From the tensile deployments, the mechanism  performed nominally.  From  high- speed video  footage, some elastic spring back of the f lexure along its  length from the release of tensile strain energy  was observed.  However,  the flexure continued onto its  deployment as driven by all the springs. This form of dynamic response was expected and deemed  acceptable.  During the deployments in compression, however, functional failures were encountered.  The  following section dives into the test failure o bservation, the respective actions carried out post -failure , as  well as lessons learned.  

Figure 12. Loaded deployment tensile test configuration. The vertical load from the crane is reacted with a  linear tensile load in the flexure. The pneumatic pin- puller fires when the crane is at the 1.2x peak load.  

During this tensile portion of the loaded d eployment testing, it was observed the GSE rotated very quickly   about the mock CDP revolute joint due to the strain energy release in the test setup.  This configuration  resulted in the GSE rotating out of the way of the f lexure  deploy  path; resulting in no interference in  deployment.  However, when flexure preload was reversed to compression, such GSE rotation after  releasing the pin -puller was also rev ersed.  As a result, this reversal caused the GSE to rotate towards the  flexure path of deployment  and subsequently  jammed the flexure;  leaving approximately half of the applied  preload stored within the system.  Once the load was relaxed to nearly zero,  the flexure was able to fully  deploy.  Upon inspection of the hardware  post-test, no damage was observed other than minor paint marring  on the flexure.  To fully ensure this anomaly was truly realistic  and repeatable, this compression test was  repeated for the final test and same jamming results  occurred.  

The cause of the mechanism jamming was determined to be a function of the test GSE . The GSE rotated  two orders of magnitude faster than the fastest predicted flight CDP rotation rate from ADAMS.  It is because  of this non flight -like, extremely high rotational rate of the CDP , subsequent jamming occurred.  More  importantly, this jamming event showed that there was a race condition designed into the hardware.    This race condition was new  and solely problematic  for the Mars 2020 CDPR.  The overall height of the  flexure linkage was big enough to completely block  a moving HSA bracket clevis if it does rotate towards  the flexure.  For MSL, the linkage was only as thick as the spherical bearings  and therefore; not big enough  to be in any vicinity of the rotational path of  the HSA bracket if the linkage was stagnate.   

To alleviate the concern of this race condition, a simulation of the fault case CDPR deployment against the  fastest ADAMS predicted rotating differential was visited. Using as -tested data from CDPR deployments,  an analytical model was created that could output the position of the flexure at any point during its  deployment. For best accuracy, all environmental conditions such as temperature, orientation, and level of  “dirtiness” were considered and properly verified from previous developmental tests. From th is verified  analytical model, the outputted flexure positions were compared against the worst -case differential position