Design, fabrication and modelling of MEMS-based microthrusters for space application

With the development of microspacecraft technology micropropulsion concepts are introduced for course correction and orbit insertion as well as attitude control of the microspacecraft. In this context, we have introduced a new concept of MEMS-based technology microthruster responding to the spatial constraints (volume constraints, high level of integration) and MEMS characteristics (miniaturization, low cost, mass production). The originality of these new thrusters is the use of only one solid propellant loaded in a small tank micromachined in a ceramic, glass or silicon substrate and the fabrication of arrays of N independent microthrusters in the same chip. The structure consists of a sandwich of three micromachined silicon substrates: nozzles, igniters and propellant chambers. The thrust force generated can be set from a few hundred µN to a few tens of mN by geometrical and dimensional considerations. In this paper we present the fabrication and assembly of one prototype: it is an array of 36 microthrusters that proved the technological feasibility of this new concept of small-scale thrusters. We also investigate the influence of nozzle geometry on the performances of our thruster.