1. NASA NASA/SP-2011-3421, probabilistic risk assessment procedures guide for NASA managers and practitioners, 2nd ed. Washington, DC; 2011.
2. NASA decision memorandum for the Administrator. Agency׳s safety goals and thresholds for crew transportation missions to the International Space Station (ISS),” Washington, DC; 2011.
3. US Nuclear Regulatory Commission, SECY-00-0077. Modifications to the reactor safety goal policy statement. March 30; 2000.
4. US Department of Energy, DOE/HS-0006. Technical basis for U.S. Department of Energy nuclear safety policy, DOE policy 420.1.July; 2011.
5. Aerospace Safety Advisory Panel annual report for 2014, Washington, DC, submitted to the NASA Administrator and US Vice President on January 28; 2015.