I-Corps: Microfluidic Electrospray Thrusters for Small Satellite Propulsion

University Of California-Irvine, Irvine CA

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project is the development of a new electric propulsion system for small satellites. Networks of satellites are used to predict natural disasters more accurately, provide better communication, and guide autonomous vehicles as well as for many other applications of global interest. Profitable missions need a propulsion system to perform orbital maneuvers, such as final orbit insertion, attitude control for precision pointing, and drag compensation to extend the lifetime of the mission or deorbit the satellite at the end of the mission, a requirement that will soon be enforced to ensure space sustainability. There are very few propulsion systems available for micro satellites (satellites under 100 kg). Electrospray thrusters, unlike other electric propulsion systems, can operate efficiently with only a few watts of power, which makes them very suitable for microsatellites (under 100 kg). At the same time, the same system can be scaled up and used for larger satellites (100-400 kg). The industry is shifting to serial manufacturing and a fast-paced, low-cost oriented vision to fulfill the demand. This technology has the potential to meet the strict time, cost, size. and performance requirements. This I-Corps project is based on the development of an electric propulsion system for small satellites. The system will provide the spacecraft with primary propulsion and attitude control to perform a wide range of orbital maneuvers. The modular approach ensures a fit with the new space industry, where constellations of satellites require systems that can be easily integrated into their platforms and that meet the low-cost and quick time requirements. Electrospray thrusters accelerate droplets and ions through an electric field, producing thrust. The thrust produced by one emitter is very low, in the order of 0.5 µN, therefore, hundreds of emitters must operate simultaneously to provide enough thrust to perform orbital maneuvers. This project develops a process to manufacture arrays of emitters using microelectromechanical systems (MEMS) technology. The emitter arrays can be arranged in modules of arbitrary sizes to meet specific thrust requirements and benefit from the advantages of MEMS manufacturing. These emitters are internally wetted, which means that the propellant flows through a capillary and it is anchored at the emitter head during operation, a desirable feature that is not found in other types of electrospray emitters, such as porous emitters or externally wetted emitters. This design may have better performances than other approaches because the emitters are coupled with a network of microfluidic channels that provide the necessary hydraulic resistance for correct operation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.