Abstract: The stress corrosion cracking (SCC) is a multi-factor synergetic failure mode, apt to cause non-omen accidents of spacecraft structures. In this paper, the SCC stresses and related microscopic factors are analyzed from a genetic view to understand the SCC mechanisms, together with their measuring methods, and the connotation of no SCC accidents. It is indicated that the SCC stress value is far below σ_S, and the microscopic SCC genes consist of dissolving anodes, hydrogen, electronegative ions, slipping dislocation, passive films and crystallography. The measurement of the SCC gene configurations and the characterization of the SCC susceptibility can be made through the detection of the multi-size fracture or the cracking morphologies, the chemical concentrations, the electrical potentials or currents, and the stresses or strains. From the view point of the SCC genes, the principle of the SCC accidents in the designed service life of the spacecraft structures can be generally classified into three organically combined parts, including a reasonable design, an accurate evaluation, and a correct failure analysis.