This year our mechanical engineering capstone team from the Maseeh College of Engineering and Computer Science at Portland State, decided to take on the challenge of building a cold gas reaction control system (RCS). The RCS was built for the Portland State Aerospace Society, a crowdfunded and open-source amateur space program / citizen science project. The RCS module will be flown on sounding rockets for high altitude launch missions. The hope is for PSAS to eventually launch a cube-sat payload into orbit, and with this device we are one step closer.

Luckily, instructables.com and Intel donated the Intel Edison board, making testing easier, safer, and hands free.

note: This system is able to use custom 3D printed de Laval nozzles to generate over 2.5 lbf (11 N) of thrust from 100psi of Nitrogen for roll and pitch maneuvers. A high resolution 3D printer (32-micron or under) is necessary to avoid viscous losses from rough surface finish.





What does this instructable offer?

This instructable is mostly open source, and all of the CAD files and some of the controller code can be found on our github account. We use 3D printed nozzles, that can be modular and optimized for specific missions; The Matlab nozzle optimization code is included. The Matlab program to determine gains for the controller, and the roll-control programs for Python and Arduino are both given. We are also including our parts list for both commercial off-the-shelf and custom parts.

What this instructable does not offer:

The purpose of this instructable is to explain a broad overview of how to build the system for amateur rocketry projects. We will not give a step-by-step guide of how to do everything. We will also not include pitch/yaw action control programs, because I don't need a guilty conscious.

Be aware that even with this guide, this is still a relatively difficult project; it should not be treated as DIY potato gun or blue tooth speaker. With that being said, it is still crazy fun to build and play with.