This paper intends to make a brief analysis of the influence of cosmic radiation on RF signal envelope detectors implemented by Microwave Photonics (MWP) techniques on board CubeSats. Such satellites are small, can operate in low orbit, and have very stringent requirements regarding power consumption, volume, and weight. Receivers based on envelope detectors assisted by MWP are candidates for boarding CubeSats. Such receivers that employ Bragg grating on silica optical fiber are influenced by cosmic radiation and end up having their Bragg resonance frequency altered. This work proposes a numerical analysis from data obtained in the literature to simulate the photonic RF receiver behavior under the influence of a 2 krad cosmic radiation load accumulated over two years of satellite operation in low orbit. The accumulated cosmic radiation, for these conditions, can cause a 10 pm deviation in the Bragg grating, which does not impact the photonic RF receiver.