Feasibility of a deployable boom aboard picosatellites for instrumentation and control purposes

Until the 1990´s, satellites grew ever larger in both size and mass. NASA administrator, Daniel Goldin, urged for a “faster, better, cheaper” approach that created a wide variety of programs including microsatellite research. Picosatellites, weighing less than 1 kilogram, are one branch of these miniature spacecraft. Their reduced size allows them to be launched in mass quantities at low cost and provides many opportunities not always permitted by larger structures. Unfortunately, while small spacecraft technology has proved to reduce cost and development time, their small size limits the possibilities of certain design concepts. One way to widen the capabilities of these small satellite systems is by utilizing a deployable boom. The boom is stowed within a picosatellite prior to launch and extends into a deployed state once in low Earth orbit. Once in space, the boom serves a two-fold purpose. First, it can be used as a passive form of control to help stabilize and orient the satellite using a reliable gravity-gradient technique. Secondly, on-board instruments could be placed at the tip of the extended boom to minimize any magnetic and electronic interference with internal bus components. Extendable booms have proven space flight heritage on larger microsatellites like QuakeSat and PRISM. Initial research, however, suggests that this concept has not been adapted to the smaller class of picosatellites. This study takes a deeper look into the history of deployable structures on microsatellites in the hope of designing a boom capable of operating within a picosatellite. Various trade off studies are performed, placing heavy emphasis on choosing a suitable boom type and deployment technique while taking into consideration well defined mass, volume, and power constraints. After choosing an appropriate boom and deployment method, a computer-aided design (CAD) model will outline the final boom design both in its stored and deployed configurations. The st- uctural integrity and physical limitations of the boom are demonstrated by performing a finite element dynamic analysis that simulates typical launch loads. Finally, a MATLAB code is utilized to simulate and verify the stability and effectiveness of the chosen gravity-gradient boom design. Introducing a deployable boom in a picosatellite allows for a reliable, inexpensive form of control while simultaneously allowing for more accurate instrumentation data by reducing system noise. By keeping cost and development time low, an extendable boom can expand the current capability of picosatellites to a wider aerospace population, including the university level.