directly to the copper lug, which takes the electrical power to the power management system. Isolating the  various electrical paths from one another involved adding a shrink tube to the hinge pin, polyimide tape to  various surfaces on the radiator and chassis (in case the superelastic springs inadvertently contact those  surfaces), and G10 fiberglass laminate composite bushings around the fasteners used to attach the springs  to the radiator.  Design Evolution, Development Issues, and Solutions  The following section discusses the design evolution, development issues, and solutions of each  mechanism, starting with the R&R and followed by the hinge.  The mechanism’s development started with proof of concepts tests. These involved building several early  low-level hardware models to test out the design ideas and options. The R&R was subjected to several  three-dimensional (3D) printed designs, which aided in choosing the design features to use and to discover  issues with the concepts. The hinge also used 3D printed hardware to prove out the concepts. In particular,  several of the latch concepts were tested quickly using 3D printed hardware. This proved to be  advantageous since conventionally machined designs can be more expensive and time consuming.  When the designs were finally matured, an engineering design unit (EDU) of each mechanism was  fabricated and tested to prove out the designs for flight. The EDU was built to be as flight-like as possible.  The test program was conducted in the summer of 2016 and included subcomponent testing such as  measuring performance parameters of the hinge SMA springs, R&R linear actuator pull force, and other  data used to correlate to analysis. The subcomponents were then combined into a system and subjected  to environmental testing. This included a random vibration test to 14.1 gRMS for 3 minutes in three axes  and in extreme cold and hot environments with margin. The EDU functioned successfully before and after  the vibration test and in the extreme thermal environments. This testing program was very successful. It  proved out the designs and discovered issues that were corrected in the final build. Though the EDU and  flight builds differed slightly, the EDU essentially acted as a qualification unit. After the EDU test campaign,  a critical design review was held to present the final design that incorporated all of the changes discovered  in the EDU tests.  R&R: Early Concepts  The final R&R in the ALBus design was the product of several iterations. Three main concepts were initially  investigated. The first was a piston design using antagonistic SMA springs where one pulled and the other  pushed to release the SAs when activated. This design never made it past the conceptual phase as it was  determined the unrestrained condition of the SMA spring in one of the directions would mostly likely be  detrimental under launch vibrations and possibly cause a premature deployment. The second concept  involved a collet design and used an SMA to free up the collet fingers. A plastic 3D printed prototype was  created and the design was moving toward development of a fully functional engineering unit. While this  concept was very promising, the mass budget and forecasted development time stopped this concept from  continuing. The mass of the entire CubeSat needs to be kept at or under 4 kg. A critical thermal issue  demanded the addition of a radiator for the primary mission objective, which reduced the available mass  for the R&R. At this point in the development of the mission, there was not enough time to redesign and  reduce the mass. This led the design toward the third and final concept described in this paper.  The final R&R design was based on prior SMA work developed at Glenn and is an SMA linear actuator  device that can be quickly procured and modified. Leveraging the second-stage loaded spring concept of  the collet design and this SMA linear actuator, the SMA driven pin-puller design was created for the ALBus  CubeSat. The moving pin frees up a secondary release plate used to constrain the deployable SAs through  two hooks on each deployable array.  NASA/CP—2018-219887 381