Online

Gagne, Kevin R.

Mechanical Engineering

2016

MS

Next generation small satellites, also known as nanosatellites, have masses significantly lower than traditional satellites. Including the propellant mass, the total mass of a nanosatellite is often in the range of 1 to 4 $kg$. These satellites are being developed for numerous applications related to research, defense, and industry. Since their popularity began in the early 2000's, limitations on the downscaling of propulsion systems has proven to be problematic. Due to this, the vast majority of nanosatellite missions have limited lifespans of 90-120 days in low Earth orbit before they reenter the Earth's atmosphere. Although satellites on this scale have little available space for instrumentation, the development in the fields of microsensors, microelectronics, micromachinery, and microfluidics has increased the capabilities of small satellites tremendously. With limited options for primary propulsion and attitude control, nanosatellites would benefit greatly from the development of an inexpensive and easily implemented propulsion system. This work focuses on the development of an additively manufactured chemical propulsion system suitable for nanosatellite primary propulsion and attitude control. The availability of such a propulsion system would allow for new nanosatellite mission concepts, such as deep space exploration, maneuvering in low gravity environments, and formation flying. Experimental methods were used to develop a dual mode microthruster design which can operate in either low impulse, pseudo-monopropellant mode, or high impulse, bipropellant mode. Through the use of a homogeneous catalysis scheme for gas generation, nontoxic propellants are used to produce varying levels of thrust suitable for application in nanosatellite propulsion. The use of relatively benign propellants results in a system which is safe and inexpensive to manufacture, store, transport, and handle. In addition to these advantages, the majority of the propulsion system, including propellant storage, piping, manifolding, reaction chambers, and nozzles can be 3D printed directly into the nanosatellite chassis, further reducing the overall cost of the system. This work highlights the selection process of propellants, catalysts, and nozzle geometry for the propulsion system. Experiments were performed to determine a viable catalyst solution, validate the gas generation scheme, and validate operation of the system.