The current push to develop small satellites, the need for formation flying constellations, and the desire to replace reaction control wheels have resulted in the need for thrusters that can deliver very small impulse bits. The required thrusters are much smaller than those available today, so new technologies will have to be developed. In Phase I, Ultramet focused on the development of catalysts that could be scaled down to the dimensions required for such small thrusters. To facilitate testing of these catalysts, Tridyne was used as the propellant, and several dozen catalyst beds were tested in a 5-lbf test engine. Several of the catalyst beds tested showed faster temperature rises and higher steady-state temperatures than a similar sized bed of Shell-405. For all of the Ultramet catalysts, the supports were monolithic materials that could easily be scaled down for use in microthrusters. Phase II will build on this technology, and enable the resulting catalysts to be used with other propellants, such as hydrazine or HAN-based monopropellants.
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