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256 MEMS and Microstructures in Aerospace Applications

FIGURE 11.18 VLM thruster mounted to Lee Corp. solenoid valve via Pyrex thermal
standoff. (Source: NASA.)

11.3.1 COLD GAS THRUSTER
The cold gas thruster is the simplest chemical propulsion system. 40–42 It typically
consists of a pressurized gas chamber (propellant tank), a gas metering valve, a
cavity chamber (gas plenum), and a converging–diverging shaped exit nozzle. By
opening a valve, the pressurized gas is accelerated in the nozzle to produce thrust.
Cold gas thrusters usually possess low specific impulse, and as a consequence, great
care is exercised in their design to insure the efficient conversion of the pressurized
fuel to thrust.
Miniaturized cold gas thrusters may become less efficient because of the
increased importance of drag. Valve and nozzle design are the most important
issues for this kind of thruster.

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