Shape memory alloys (SMAs), are a class of metals that possess the capability to recover substantial deformations resulting from applied mechanical loads through a solid-solid phase transformation. Typical deployment systems for solar arrays on microsats only allow for one-way deployment. However, by using an SMA actuator in place of a conventional deployment system, repeatable deployment and retraction can be achieved. Relative to conventional actuators, SMA-based solid state actuators offer a reduction in the weight, volume, and overall complexity of the system. In this study, a design of an SMA-based solar panel deployment mechanism for a typical microsat is presented. In this design, a conventional actuation system is replaced with a system of SMA torsional actuators, which allows for a deployed and stowed phase to be reached independent of environmental conditions. This design study illustrates that an SMA-based solar array deployment system can provide a viable replacement for a conventional deployment system while significantly reducing the deployment system weight, volume, and complexity.

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This paper describes a framework to quantify the effect of freestream turbulence, generated by mixing processes in a combustor, on turbulent boundary layer loss generation in the high pressure turbine downstream of the combustor. The regime of freestream turbulence common to gas turbine aero engines is identified and it is shown that the dissipation loss coefficient in this regime can be determined using existing measurements of the effect of freestream turbulence on skin friction. The paper shows that combustor-generated freestream turbulence can increase the profile loss coefficient of a typical high pressure turbine blade by as much as 28%. A relation has been derived between a non-dimensional turbulence parameter, which characterizes the freestream turbulence, and the increase in turbine boundary layer dissipation, which quantifies the decrease in turbine efficiency. The relation provides guidelines for combustor turbulence modifications that lead to turbine performance benefits. The framework has been applied in example trade studies which show that increasing the size of dilution ports and increasing the length of the combustor can decrease high pressure turbine profile loss generation to potentially increase stage efficiency up to 0.5%.

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Angela Olinger is an undergraduate mechanical engineering student at Texas A&M University graduating in May 2018. She plans on completing her Master's of Science degree after graduation before going on to work with materials design in the space industry. She is also a classically trained ballet dancer and continues to enjoy dancing and choreographing. Mr. Preetam Small Team Agile Systems Engineering For Rapid Prototyping of Robotic SystemsEngineering management decisions play critical roles in the ultimate success or failure of a project. The approach taken, the team size, the deliverables and their respective due dates, and the environment are key factors which engineering managers, technical team leads, and educators must all address to complete an assigned goal. While many courses at both the high school and college level focus on achieving set educational outcomes, the manner by which these outcomes are achieved may prove difficult to select due to the dynamic nature of the classroom. From the observations of this team, high school and university project deliverables and educational expectations are commonly, and sufficiently, satisfied by a small team of individuals, and thus it is the focus of this paper to discuss the group dynamics and structure, and the advantages and disadvantages, of the small team approach to engineering challenges. In addition to addressing the role of team size on project completion, an investigation into benefits of the agile systems engineering approach towards technical projects will be discussed with specific regard to the deliverables and time management, learning outcomes, long term project success, knowledge retention, and the learning environment. Finally, it is the goal of this paper to also highlight from the perspective of the students the benefits and challenges of working on a small team with an agile systems approach towards difficult technical challenges.