Scalable Flat Panel Nano-Particle Thruster
- Paper number
IAC-06-C4.P.4.03
- Author
Mr. Louis Musinski, University of Michigan, United States
- Year
2006
- Abstract
A new electrostatic thruster technology is being developed at the University of Michigan using nano-particles with micro- and nano-electromechanical systems (MEMS/NEMS) fabrication technology. The use of MEMS/NEMS technologies appears to mitigate life-limiting physical characteristics present in state-of-the-art ion propulsion by eliminating the need for a discharge chamber and reducing charge-exchange (CEX) collision effects in the thruster’s ion optics. Further, by considering the use of nano-particles as a propellant with electric field-emission based MEMS/NEMS thruster concepts, important new performance improvements appear possible. These include (1) the ability to continuously vary the specific impulse (100 s – 10,000 s) by simply changing nano-particle size and shape, (2) operations at very high efficiencies over the entire Isp range, (3) operations at high power levels at much lower system-level specific mass, and (4) an increase in thrust densities over present-day ion thrusters. The nano-particle electrostatic propulsion concept, called nanoFET (nano-Field Emission Thruster), is a scalable flat-panel thruster that can be designed for variable power and particle sizes. The use of nano-particles should be contrasted with the formation of small droplets as in field effect electric propulsion (FEEP) thrusters. In FEEPs, charge extraction produces instabilities that result in the formation of charged colloids. While these microscopic droplets could in principle be used to accomplish the same goal as our nano-particles, colloids result in efficiency losses due to Taylor cone formation and exhibit a distribution of sizes that decreases thrust controllability. Our nanoFET propulsion concept avoids the conditions that generate colloids and allows us to tune the nano-particle size independently of other factors. At the core of the flat-panel thruster are millions of MEMS/NEMS-based micron-size vias that have a multi-layer grid to establish the electric fields necessary to charge, extract, and accelerate conducting nano-particles. These nano-particles range in size from below 0.1 nm to over 100 nm, and they can be transported to the particle extraction zones in either insulating or mildly conducting liquids. We have developed and are currently performing a series of experiments to demonstrate the feasibility of nano-particle propulsion. The objectives are to 1) characterize the behavior of particles in liquids subjected to an electric field, 2) control particle extraction through the liquid interface, and 3) optimize liquid and nano-particle characteristics for in-space operation.- Abstract document