Among chemical propulsion device, bipropellant thrusters, in which oxidizer and fuel are separately stored in individual tanks, have relatively high specific impulse, which expresses how little propellant is necessary for yielding a certain thrust. Moreover, the thruster is readily throttleable simply by adjusting mass flow rate of propellant whereas solid propellant thrusters have difficulty in start, interrupt, and restart of combustion as well as variable thrust. Hence, most thrusters on satellites are bipropellant thrusters using Unsymmetrical Dimethyl Hydrazine (UDMH)/nitrogen tetra oxide (NTO) propellant.

On the other hand, conventional bipropellant thrusters have some unfavorable characteristics. The thruster necessitates tanks and valves and consequently has more complex structure than solid propellant thruster. Propellants such as UDMH and NTO are very toxic and reactive to materials for propellant feeding devices. Hence, in ground tests, a special system is necessary for exhaust gas treatment. For augmentation in performance, atomization is necessary when the propellant is injected into thrust chamber because evaporation of liquid propellant is a rate-determining process in combustion.

From these points of view, we proposed to use nitrous oxide (N₂O) and dimethyl ether (DME) as a green bipropellant for thrusters. Neither N₂O nor DME is toxic; N₂O, i.e., the laughing gas, is used as anesthetics and cooking spray; DME is used as a propellant for gas dusters. Today, some research groups tries to apply DME to diesel engine.

N₂O and DME are stored in a liquid form without cryogenic device; N₂O DME have vapor pressures of 5 and 0.6 MPa at the room temperature, respectively. The propellant can be readily evaporated or liquefied by adjusting temperature and pressure. The vapor pressure allows the propellant to be fed in a gaseous form into thrust chambers, and resultantly requires no atomization. This will downsize and simplify thrust chambers and injectors.

Chemical equilibrium calculation showed that N₂O/DME propellant yields a maximum theoretical specific impulse of 287 s at oxidizer to fuel ratio (O/F) of 3.5. The specific impulse is smaller than that of conventional liquid propellants; NTO/UDMH thruster yields a specific impulse of 320 s. Nevertheless, N₂O/DME bipropellant thruster neither toxic nor reactive to materials.