New space applications such as orbital control of micro-satellites and precise interferometry have created a demand for high precision, low thrust efficient space engines. Electrospray propulsion is a serious candidate for this new technological niche. Electrospray thrusters are space propulsion electric engines that take advantage of an electro-hydrodynamic effect known as Taylor cone to produce thrust. When this effect takes place, charged particles are expelled from the apex of a conductive liquid meniscus deformed into a conical shape; this shape results from the equilibrium between surface tension effects and electrostatic pulling on the meniscus surface. Electrospray thrusters are well suited for scaling down and batch production because these engines do not require large pressure ratios to achieve high efficiency, or high temperatures or plasma phase ionization to operate. Electro-spray thrusters can deliver thrust in a very precise way. Furthermore, they are able to match the requirements of any conceivable mission that any of the other space propulsion electro-magnetic engines can achieve because it is possible to use the same engine and propellant to span a wide range of Isp's and thrusts. This capability is due to the series of different regimes that the emitters could operate in (droplet emission, solvated ions and mixed regime). The present work tackles the problem of how to fabricate a colloid engine with large emitter density using micro-fabrication techniques, and demonstrates that highly packed colloid thruster arrays are feasible. The work is centered on two engine concepts: an internally fed linear colloid thruster array (with highly doped formamide as propellant-intended to work in the droplet emission regime), and two
展开▼
