Micro thrusters

Assuming that similar exit velocities can be achieved at micro- and macroscales, the thrust is proportional to the mass flow, hence to the cross-sectional area or to the square of a characteristic length scale F oc m oc A oc. The thrust to weight ratio of a micro thruster is therefore expected to increase as it is miniaturized ... 

As described above, many approaches can be taken to convert energy at small scales. This section describes some of the achievements and challenges identified in three of the most researched areas for which microfluidics are of central importance micro fuel cells, micro heat engines, and micro thrusters. The focus will be on device implementations that leverage MEMS and microfabrication technologies. 

As Fuel for Micro/Nanosatellites Using Laser Plasma Thrusters... 

Examples for the second group are polymers as fuel in the micro laser plasma thruster (JJ.LPT), PLD of polymers, matrix-assisted pulsed laser evaporation (MAPLE), which is a deposition technique that can be used to deposit highly uniform thin films [26], or laser-induced forward transfer (LIFT) [27-29], which can be used to produce microstructures by transferring an irradiated area of a target film to an acceptor substrate. The polymer can be the transferred material, or just functions as driving force in the transfer. 

Moreover, there is a current need of miniaturized propulsion system for widening the capabilities of low cost micro-satellites. Recently, the development of a turbo-pump fed miniature rocket engine has been proposed as a new propulsion system for micro-satellites (10 to 100 kg) [6] the bipropellant tlmister uses 70 wt.-% H2O2 as oxidizer and ethanol as fuel. The engine displays four sub-components (i) two propellant micro-pumps, (ii) a HP decomposition chamber, (iii) a turbine coupled to an electric power generator and driven by the hot gas released from HP decomposition, and (iv) a thruster for the combustion reaction. 

Thrusters can be used in either continuous or pulsed operation, according to the application. Miniature rocket launchers and micro air vehicles require a continuous thrust and are best served by a unique thruster or engine with a continuous feed of propellant. Alternatively, digital micropropulsion refers to an array of single-use thrusters that provide a small impulse (short burst of thrust) to accurately orient a small spacecraft or correct a vehicle s trajectory. 

Hmby MG-CV, Falkos P, Shenoy S. Micro newton colloid thruster system development. 27th international electric propulsion conference. 2001. 

---