Abstract: A microthruster (11) provides a small unit force. The microthruster is useful, for example, as a propellant for a microsatellite. The microthruster includes an aerospike (12) extending outwardly beyond the face of an outer wall of the chamber (14) of the microthruster in the vicinity of an outlet nozzle thereof formed by two diaphragms or burst disks (15, 16), closing the chamber on respective sides of the aerospike. The aerospike is preferably formed integrally with the chamber by batch microelectronic fabrication methods. Higher thrust efficiency and more controllable and uniform impulse characteristics are attainable with the microthruster and with an array (17) comprising a plurality of the microthrusters.