Chemical reactors are physical systems particularly well-suited for scaling-down and multiplexing. Chemical reactors are well-suited to scaling down because most chemical reactions are diffusion-limited, and hence increasing the surface-to volume ratio of the reactants favors faster reaction times and more efficient by-product transport. As in the case of electrospray, the hydraulic impedance that backs up each reactor plays a leading role in the implementation of massive arrays of reactors. In our work, we optimize the chemical reactor given a set of conditions set by the physics of the process and the requirements of the application, to then multiplex the reactor to visibly augment the throughput with no loss in performance. We have developed a singlet oxygen generator and a hydrogen peroxide steam generator. Both technologies were originally developed for the chemical oxygen iodine laser (COIL) but they can be used in other applications. For example, the hydrogen peroxide steam generator can be also used as green monopropellant rocket to satisfy the impulsive maneuvers of nanosatellites.