Free Software and High-Power Rocketry: The Portland State Aerospace Society

The Portland State Aerospace Society (PSAS) is a small, low-budget amateur aerospace group. PSAS is currently developing medium-sized sub-orbital rockets with the eventual goal of inserting nanosatellites (satellites that weigh less than 10 kg) into orbit. Because achieving orbit requires a navigation system able to guide the rocket along an orbital trajectory, PSAS is pioneering an open source and open hardware avionics system that is capable of active guidance. In this paper, we describe how free software and open hardware have dramatically changed the capabilities of amateur aerospace groups like PSAS. We show how we have applied existing and custom free software to the avionics and ground support systems of a sub-orbital sounding rocket, and discuss what further work must be done. We conclude that the sophistication and complexity achieved by current amateur avionics projects—which are beginning to challenge the distinction between amateur and professional—would not be possible without the use of free software.