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In the space field, the recent advancement in the Micro-Electric-Mechanical Systems (MEMS) technology has allowed for the development of small satellites (total mass less than 20 kg), thanks to the reduction of the total expenditure of space missions under Low Earth Orbit (LEO). Micro-and nano-satellites usually require very small thrust forces in order to ensure the orbit and/or attitude control, from few micro-newtons up to some milli-newtons, in combination with stringent constraints of mass, volume and power consumption to be satisfied. Therefore, the micro-propulsion system represents a key technology, and water-propellant micro-resistojets provide a green and reliable solution in the class of electric propulsion. The present work first describes the final design of a low-cost, flexible, silicon-based waterpropellant vaporizing liquid microthurster (VLM) prototype. The VLM composes of an inlet chamber, a set of parallel microchannels as heating chamber, and a planar convergentdivergent micronozzle. The microthruster has a sandwich structure. The inlet chamber, the heating chamber and the micronozzle have been fabricated using anisotropic wet etching of a silicon substrate coupled with specialty Borofloat 33® glass. The Borofloat wafer was coupled to silicon wafer by thermocompressive bonding, which allowed to ensure one optical access to the flow field inside the microthruster. A Platinum resistive film placed on the bottom of the silicon pad provides the heat required for vaporization and superheating. In addition, the microthruster is equipped with sensing capabilities for the temperature and the vapor quality, thanks to a of thermistors …
Plan. ed srl
Publication date: 
30 Sep 2019

Maria Grazia De Giorgi, Donato Fontanarosa, Luca Francioso, Chiara De Pascali, Antonio Ficarella

Biblio References: 
Italian Association of Aeronautics and Astronautics-XXV International Congress