Abstract: Propulsion systems that generate thrust from pressure generated by thermally decomposing a chemical blowing agent (CBA). In some embodiments, the CBA decomposes exothermically such that once thermal decomposition has been initiated, the thermal decomposition continues without additional energy input. In some embodiments, the CBA is utilized in a digital-microthruster array containing microthrusters that can be individually activated to provide thrust. In some embodiments, a CBA may be stored in one or more CBA-storage chambers that can be individually activated to charge and/or recharge a pressure tank that stores gas from the CBA decomposition under pressure for providing thrust. These and other embodiments are disclosed. Such propulsion systems can be used for any of a variety of spacecraft, including micro- and nano-satellites. Corresponding methods of generating thrust are also disclosed.