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Abstract The spacecraft “PurdueSat”, classified as a nano-satellite, is currently being developed by the School of Aeronautics and Astronautics at Purdue University. The primary mission of ‘Project PurdueSat’ is to achieve stable satellite orientation by performing precise attitude and pointing control using propellant-less methods. The solution for attitude determination and control is unique in that it's based only on the interaction between the magnetic moment generated by the satellite and the earth’s magnetic field. This calls for highly complex mathematical models and enormous numeric data processing at runtime. Therefore, the computational demands along with an ultra low-power scheme were the primary design drivers in the choice of the flight computing platform. ZMobile “The ZMobile mixed signal board based on the LabVIEW Embedded Module and the Blackfin is a promising flight computing platform for high-end nano-satellite applications, since it combines an ultra low power scheme with enormous numeric processing capabilities. Thanks to high-level graphical programming, DSP power becomes now accessible to Aerospace Engineers, who may not necessarily be embedded system experts.” states Paul Moonjelly, the Project Manager and Systems Engineer for the Purdue CubeSat Program. Engineering Services Schmid Engineering, a Swiss solution provider for embedded systems based on the NI LabVIEW Embedded Module and ADI Blackfin, is collaborating with Purdue in developing and implementing the Flight Computing System Software. A reliable real-time framework with a smart power and error self-correction scheme suitable for long-term space applications is being developed as part of this venture. Schmid Engineering applies knowledge gained from a recently successfully installed long term sub sea monitoring system which is based on the same technology. Conclusion The Purdue’s CubeSat has a unique mission to push the frontiers of nano-satellite technology towards precision attitude estimation and accurate attitude control (using electromagnetic coils alone). The mathematically intensive Attitude Determination and Control schemes could be implemented on the tiny CubeSat with challenging space and power constraints due to the choice of the Zmobile computing platform – a low power mixed signal platform driven by the NI LabVIEW Embedded and the ADI Blackfin processor. Graphical embedded system design using LabVIEW Embedded has significantly accelerated the PurdueSat design and development, carried out by a small group of Purdue Aerospace engineers. Upon completion, the spacecraft will be launched aboard a Russian Dnepr or similar launch vehicle, in conjunction with the Cal Poly/Stanford CubeSat program. Cal Poly’s standardized CubeSat deployment system - the P-POD1 - would then eject the CubeSat giving it a soft kick (using a spring plunger which ensures a low spin rate2) once the launch vehicle is at a desirable altitude somewhere along the path of the primary payload destination. The PurdueSat deployment switches would be triggered after ejection and the satellite would start its mission (after a small time window that allows for safe separation). Download the whole Paper here (480kB)
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