Yvonne Madelaine Claeys Brill was a Canadian-born American aerospace engineer rocket scientist who pioneered the electrothermal hydrazine thruster. She called it hydrazine resistojet. Resistojet is a system of spacecraft propulsion that delivers thrust by heating a non-reactive fluid. Yvonne Brill patented her propulsion program for satellites in 1972. She gained U.S. For the last twenty a long time of her life, Yvonne C.