In this work, we report a comparative study of the gamma ray stability of perovskite solar cells based on a series of perovskite absorbers including MAPbI3, MAPbBr3, Cs0.15FA0.85PbI3, Cs0.1MA0.15FA0.75PbI3, CsPbI3, and CsPbBr3, where MA = methylammonium, and FA = formamidinium. We reveal that the composition of the perovskite material strongly affects the radiation stability of the solar cells. In particular, solar cells based on the MAPbI3 were found to be the most resistant to gamma rays. This was explained by the defects formed in the materials undergoing rapid self-healing due to the dynamic behavior of this system. Fully-inorganic as well as mixed cation perovskite formulations did not deliver comparable stability due to the special gas-phase chemistry analyzed with ab initio calculations, which occurs in MAPbI3 but does not in other perovskites. In the case of multication perovskites, such behavior can be at least partially attributed to the phase segregation effects induced by gamma rays. The fact that the solar cells based on MAPbI3 can withstand 1000 kRad gamma ray dose without any noticeable degradation of the photovoltaic properties (besides that induced by glass substrate darkening) is particularly exciting and shifts the paradigm of research in this field towards designing more dynamic rather than intrinsically robust (e.g. inorganic) materials. The established relationship between the absorber materials composition and their radiation stability in devices paves a way for designing a new generation of perovskite photovoltaics for space applications.