In 1995, the NASA Systems Engineering Handbook (NASA/SP-6105) was initially published to bring the fundamental concepts and techniques of systems engineering to the National Aeronautics and Space Administration (NASA) personnel in a way that recognized the nature of NASA systems and the NASA environment. Since its initial writing and its revision in 2007 (Rev 1), systems engineering as a discipline at NASA has undergone rapid and continued evolution. This revision (Rev 2) of the Handbook maintains that original philosophy while updating the Agency's systems engineering body of knowledge, providing guidance for insight into current best Agency practices,