This paper presents a method to predict the I-V characteristic of triple junction InGaP/GaAs/Ge solar cells when different illumination spectra are used, and it is based on the measurement of a set of commercial isotype cells together with numerical simulations. The study includes the utilization of continuous and pulsed light sources. Several spectra were considered for the continuous light sources, where different subcells limit the current of the tandem cell. For pulsed light sources, a dynamical analysis was carried out by simulating a triple junction cell through PSpice software. For the simulations, the subcell capacitances were estimated and introduced into an electrical model of the triple junction. When a fast pulse in the multiflash I-V measurement technique is used, dynamical effects associated with this kind of source were observed and accounted for by the simulations. It was established that the dynamical effects did not affect the I-V characteristics measured with this technique. Finally, the proposed method and analysis were successfully applied to the electrical characterization of the Aquarius/SAC-D Argentine satellite solar array modules.