Pin Puller Implementation of JPL’s standard Pin Puller turned into anoth er development process, since there were  no guidelines or requirements on appropriate mounting techniques, clearances, tolerances, etc. The only  verbal direction was to mount the Pin Puller so that no side-loads were put on the Pin, requiring adjustable interfaces for Pin alignment. The Pin was rated for loading in double shear, but there was no  definition of how that condition was to be created. With a standard tongue-and-clevis arrangement (Fig.  2), and the clearances needed between each, appreciable four-point bending was introduced. The device had to stage deployment of the LDM, without restraining the dynamic motions of the Boom during launch.  FEM analysis predicted the amplitude of Boom motion, and the hole in the Tongue was oversized  accordingly. This would lead to an impact load against the Pin after Reflecto r separation, but the driving  load case actually resulted from the UDM deployment hitting its Hardstop. While the Inconel Pin was  extremely strong, the materials preferred for the Tongue and Clevis all showed significant yielding from  the bearing stresses. This yielding added to the bending moment (now in three-point bending) and side  loads put on the Pin, and t here was concern that the yielded ma terial could get extruded into the joint and  cause binding. Despite its load rating, the Pin Puller had to be analyzed. Predictions of the material extrusion were also made, and chamfers were put on the edges of the holes to accommodate it.  Thermal Blanketing The Mechanisms were to be blanketed with Multi-layer Insulation (MLI). Initially, this was envisioned as a  flexing “boot” around the entire Hinge. Ho wever, the complexities of designing a dynamic, flexing blanket  that would not interfere with the deployment were daunting. The unfavorable testing and validation process won out over the thermal concerns of solar trapping in the unblanketed cavities, and the concept  was dismissed in favor of independent, static blanketing and surface treatments of the Axle, Clevis, and  Damper.  Fabrication/Procurement  An LDM brassboard unit was built in aluminum to validate Latch design, assess manufacturability and  fabrication tolerances, validate the assembly process, validate the stiffness model (though testing never  took place), and was used to measure pyroshock levels on the electronic parts due to the Pin Puller. The brassboard came together quickly and wound up being extremely useful, in that it clearly pointed the way  though several design crossroads and helped alleviate some lingering design concerns. Stereolithography models were also made as cable and blanket mockups. By going to the effort to make them  fully articulating, they wound up becoming invaluable for all sorts of unexpected purposes such as  verifying interfaces and assembly procedures, developing microswitch locations, testing the Cable Spool, and simply as a visual aid for conveying information. The lesson learned was to prototype early and often. In contrast, obtaining the flight hardware proved to be quite difficult. Vendors were late. Parts were  dropped on the floor, or scrapped on the last machining operation. One shop was even broken into and  had its computers stolen. A large percentage of fabricated parts arrived out of spec and had to be fixed or  remade. A number of discrepancies slipped through the in spection process and were not discovered until  assembly. Parts were also “lost in the syst em”, only to show up days after the replacements arrived.  Worst of all, acceptable parts were destroyed through careless handling and during simple operations  such as installing alignment pins. While everyone agreed that such a large number of problems was atypical, there was little solace in the appreciation of just how right Murphy had been. Assessing the  impact of all the problems, and determining the proper courses of action became a second full-time job.  The lesson learned was to only use vendors with a demonstrated history, and even then to take an active  role in every step of the process, i.e., via site visits, meeting with the machinists, routine status updates  with pictures, personal shepherding of th e items through processing, etc. Bearing procurement was nearly as frustrating. Between initial investigation and placing the actual order,  lead time doubled and became unworkable. As a result, a frantic search for suitable off-the-shelf bearings  was launched. This was complicated by the need for proper certs, but eventually IBSCO and Jamaica  Bearings Co were able to locate and deliver th e required items (or acceptable  substitutes) from  warehoused stock. The Damper bearings would not be identical to the heritage ones, but analysis indicated they would suffice (fortunately, one of the changes implemented in the new design also resulted  243